Pearson 365 and 367

Ok, so I'm getting new batteries and have to redo some of the old wire. Both 4D batteries are shot, but the starter battery is still good.

Batteries will be four US Battery US2200 XC 6v batteries @ 232 AH.
Two of them wired in series, the two pair wired parallel.
Here is the diagram.

1. Is this going to work?
2. What am I missing
3. What meter do I need (current meter is analog volt meter)
I want to measure volts coming out of alternator and I don't know what I want to measure on the house bank, any recommendations on amp/volt/AH meters?
4. I suppose I need to have some kind of measure on the start battery to keep an eye on that. A meter that shows the voltage of the starter battery?

5. When wiring  alternator output directly to the house battery, does the wire have to be wired directly to the battery's positive terminal or can it go through a bus bar, as shown in diagram?  Same question for the echo charger lead to the house bank. Dashed lines indicate input cable going directly to the positive terminal, rather than through a bus bar.

The diagram is drawn in normal operating position, where the 1-both-2-off switch is on 1, connecting house bank with DC panel and ON/Off set for On so starter pulls from starter battery.

alternator is wired to house and echo charger sends excess to starter.
110volt battery charger connected directly to both banks  (starter and house).

If starter battery fails, I change it Both and use house bank to start engine.
If house bank fails, I change to 2 and use start for house (hope I don't do that accidentally!).

Thanks,
Craig

Craig,
OMG, I don't know where to begin. You say your house batteries failed? I'm not surprised. But listen carefully.

My Rule#1.  Never permanently connect batteries in parallel. 1 dead 6 v house battery will guarantee 4 dead house batteries if not also fire with your schematic.

You actually show a system with 3 battery banks. House 1 (2 6v bats in series) and house 2 (the other 2 6 v bats in series) and battery 3 is the start battery. Note: do not connect the 6 volt batteries in parallel either as your schematic shows. Remove those links across the middle. Series connect batteries only.

Connect HB1 series pair and HB2 series pair (through separate fuse links) the 1,2 or both switch. The common goes to the DC panel as shown. When the boat is unattended select 1 or 2 only. Never leave the switch in both position unattended. Before selecting both always measure the voltage on HB1 and HB2 to ensure both are good.

Connect the start battery to the starter. You can use a series switch if you want but do fuse within 11" of the battery terminal.

Now you can install another switch I call the "jump start" switch that connects the start battery to the 1,2,both switch common (to the DC panel) This will allow the house batteries to be used for starting the motor if the start battery fails. Always leave this switch off unless you need it. (you will also need it to facilitate charging. Unless you go with the smart isolator described below)

Charging the 3 banks equally will be a constant problem. To only way to ensure a full charge on each bank is to select them one at a time to be connected to the alternator. The voltage drops are unpredictable so I can't say what will occur if you try to charge all 3 banks simultaneously. Based on voltage IR drops, one battery will always charge fuller than the others.

A better solution is to invest in a Sterling Pro split R zero drop- battery isolator. Alternator goes to one input and 3 high current charge wire  outputs go the each of the three banks. The splitter is zero voltage drop and smart so it will favor the battery that needs charging the most and then move on to the other 2 banks. Current will not flow between batteries though the isolator.

I am installing one right now in conjunction with a smart external regulator. The smart regulator has a sense wire that goes to the battery terminal and provides charge and float voltage per battery chemistry.

A 3 position switch with a wire to each bank will allow you to monitor all 3 battery voltages with a volt meter. This voltage alone will tell the state of each bank and if it is charging when the motor is running. A alternator current meter and shunt is a nice feature also. But I use my current meter shunt at the DC panel feed to show house drain in amps so I can calculate AH usage over time. Perhaps more useful.

With a little trickery a single pro split R can be used with the alternator and the shore power charger together.

I building out my boat with the system described above. The only other difference is my batteries are all AGM. No acid, fumes or explosive gas. AGMs will deep cycle forever it seems.

Pay equal attention to the return (Neg) cable. They carry the same current as the + cables.

Redo your schematic and I'll be happy to review it for you.    Pete W

Pete offers some excellent advice and well worth incorporating into the revised schematic. In respect to charging multiple battery banks, the Echo charger as shown manufactured by Xantrex is similar to the Sterling Pro but designed for a second battery only.  The Echo monitors the main (house) bank as they are being recharged either form the ships alternator, shore power charger, generator or solar system.  As the main batteries reach a level of around 80% of charge, the echo begins to transfer power to the 2nd connected battery, in your case the start battery.  As the main batteries reach a higher and higher level of charge the echo transfers more and more of the power to the start battery automatically.  The amperage that the Echo will transfer is limited to a maximum of 15 amps but that is more than sufficient for a top off charge to the start battery.

Having the Sterling or the Echo eliminates the requirement for a human to manually shift the available recharge power to the desired batteries and both units assure the most efficient method of recharging all the ships batteries.

While we are talking electrical systems and their associated components, I would like to reinforce that a ships electrical system design is only as good as its design, installation methods and the components that it is made up of.  Having used Blue Seas components many times in the past, I would like to suggest reviewing what they have to offer.  Even something as standard as the 1/2/both main switch, Blue Seas has several in different power connection configurations.  The last one I purchased even  offers a glow in the dark dial.  This simple but effective idea is a wonderfull thing when walking aboard in the dark of night.

One last thing... do not underestimate the importance of installing fusing at the batteries.

Dale

I suspected I had to make some modifications.
Dale and Pete,  thanks for the recommendations.

1. Fuses: one on each positive battery cable, where else?
2. Battery charger output: To the Alt In on the Sterling SplitProR or to the pos terminal of each bank?
3. Sense wire from smart regulator (existing Aqualine regulator): Does it go to one or both house batteries or to the Sense terminal on the SplitProR, or somewhere else?

Here is the modified schematic.
Thanks again for your help.
Craig

Actually, it is better to wire the 4 six volt batteries they way you had them.

You have more usable Amp hrs available by combining 4 six volt batteries in a common bank (via parallel and series wiring) than you do by setting them up in 2 separate banks.

The one battery goes dead scenario is a red herring fluke, but easily overcome by switching one wire, until you buy a replacement.

I have a similar wiring/battery set up to yours, but the alternator charges the starter battery first then starts on the house bank.

Shore Power and the solar system charge the house bank first then top up the starter battery.

This is accomplished through an ACR that is bidirectional.

I use MRCB breakers instead of fuses at the battery connections.

And a Blue Sea Main Panel that switches both banks on, plus lets me combine them for starting if needed.

http://slokat.com/Wind%20Tamer/pics/panels1.jpg

Well, I'm a little confused.

Slokat, I understand what you are saying about the combined bank and more usable amps. That is why I set up the first diagram.

Pete, if I understood you correctly, when I switch my 1-2-both-off switch to Both, I parallel the two banks and achieve the same as wiring the two series banks in parallel, creating a single bank of 464 AH. You implied that this is what should be done  when out on the boat, but when leaving the boat alone The switch should be switched to 1 or 2 to preserve one bank. 

Setting the charging aside for the moment and examining the "use" aspect of this, with Slokat's wiring, I get max AH all the time and don't have to worry about manually paralleling the batteries, but if one batteries fails, I can't unparallel the banks.

With Pete's recommendation, I have the advantage of paralleled banks and can manually unparallel in the event of battery failure; however, I have to remember to parallel them with the switch and to not parallel them unless both banks are at same charge level.

Is that the only differences in the two diagrams, from a "use" aspect?

Batteries are designed and rated to have a certain number of available amp hours.  Each manufacture publishes those numbers so the consumer can make an intelligent decision on the selection and purchase of such a battery.  Some publish them in such a way that hides or misleads the reality of their product but most are quite forth coming. 

One such number is CCA which stands for cold cranking amps.  This is the number of amps that a battery will provide over a 30 second period of time at 32 degrees F.  This number pertains more to automotive applications and starting your car on a cold morning.  Marine battery manufactures modify that number somewhat and refer to the MCA or marine cranking amps as most boats will not be used in 32 degree weather.  The higher the number the more power the battery will provide. The CCA and the MCA are most usefull in start battery applications.

Another number that is usefull when selecting a battery is the Amp-Hour rating.  This is the ratio of amps over a period of time that the battery will supply.  A battery that is rated at 100 AH's will provide 100 amps of power for a period of 1 hour or 1 amp for a period of 100 hours or any ratio in between.  This is a much more usable number for our house batteries.  If your total connected load is 10 amps (lights, autopilot etc.) and you have a 100 AH battery, that stuff will run satisfactorily for 10 hours. 

Same goes for recharging, sort of.  When the time comes to replace that energy, you would have to put back 100 amp hours either at 10 amps for 10 hours, 5 amps for 20 hours and so on.  Remember, amps are like dollars.  If you have 100 dollars and running a light bulb costs $1/hr you could run that light for 100 hours before you run out of power. 

I said all of this because if you have four batteries that each contained 100 amp hours a piece, their total combined amp hour rating would be 400. It matters not how they are connected, 4 x 100 = 400 period.  Parallel, series or the big circle route, the numbers are the numbers.

Now we will address the red herring issue.  Everything in this world has a tax associated with it. Cars do not roll forever when the engine is shut off. There is a tax between the tires and the road surface and the skin of the body and the surrounding air. This tax is known as friction.  Batteries have the same taxation going on internally.  Energy is lost from resistance of the materials that the battery is made of.  The electrolyte has a resistance and the sulfides you hear of are big tax collectors. The bottom line is all batteries will go dead just from their own internal resistance (taxation) all by themselves.  They all do and each does at it own rate of taxation with some faster than others.  If you connect several batteries together that internal taxation will drain the others at the same rate it drains itself.  The single weakest link of a chain limits the overall chains strength.  Same with batteries and it happens everyday, every hour, every second and it is not a fluke.  Like taxation it is a fact of life. 

Like taxation, the people that think ahead and learn form the past make better decisions and minimize their tax burdon.  Connecting batteries are much the same exercise.  Connect them in a way that the takers (entitlement types) benefit from and even the best most powerful battery will die a slow and agonizing death.  Connect them in a way that the takers are on their own and the best batteries live on long after the slackers are gone.  Sometimes you have to "loose" a cow to save the heard. Such is the case with batteries, redistribute the wealth and flush the country... um... I mean the lights.

Dale

Phantom has a battery system similar to your diagram.  The house bank is four wet cell 6v batteries wired to create one 12 v unit .  The starter battery is a single wet cell 12v unit.  The house bank is wired to a off/1/both/2 battery switch.  The starter is wired to an on/off battery switch.  The house bank "1" setting goes to house loads and the "2" setting goes to the engine starter.  The starter battery switch goes to the engine starter.  The batteries are connected by a battery combiner that is bi-directional.  Placing the starter battery switch to "on" and setting the house switch to "both" will make the starter battery available to house loads.  The alternator connects to the house bank.

I chose to create a single large house bank to help prevent a frequent deep discharge potential.  I also realize the eventual problem with a single battery in the bank becoming a problem.  A good rule of thumb is keep all batteries the same type and replace them at the same time. 

I use digital voltmeters from Datel to monitor each battery bank.  I institute a charging cycle when the house bank shows a low of 12.2v.   

I would strongly recommend reading and digesting this topic in publications like Nigel Calder's "Mechanical and Electrical Manual" to see the various ways to create a battery system.

Craig,
Your new schematic is much better IMO. To simplify further you could run the "jump start switch" directly to the lower start battery +12 bus. The engine shut off switch would connect directly to starter with one single cable.

I have been trying to get a look at the ABYC regs in section E-10 on storage devices. But its not available without $50 first. But in my search I could not find any expert (something I am not)with enough liability insurance perhaps to recommend connecting two 225 AH battery 12V banks in parallel. They all recommend the 1,2, both switch for mutilple battery systems on a boat.

I found this article from the Boston Whaler Co. that does a nice job of explaining the disadvantages of connecting battery banks in parallel.

http://continuouswave.com/whaler/reference/dualBattery.html

To paraphrase it says "connecting two batteries in parallel guarantees the battery bank will perform no better then the weaker of the two batteries in the bank." I believe that is similar to the lesson of Dale's analogy. Batteries in parallel do not share current equally meaning one of the 2 will supply the bulk of the load current.

Basically they give 2 times when you "switch" the banks in parallel. 1. to get max current for starting the motor and 2. to fast charge the banks simultaneously.

In regards to 1. (start current) I cannot image that you ever need 4,000 amps to start your motor. Having that much energy at your disposal is frightening. But you have this option with the schematic you have.  In regards to 2., The Pro R split (or blue Ocean) smart isolator will eliminate connecting batteries banks in parallel in order to charge.

The Boston Whaler article does say that failure of one of the parallel batteries in a parallel connection could result in a fire. They also warn against switching a good battery in parallel to a dead battery. This is where to volt meter should always be looked at first.

On my boat I did not use a 1,2 or both switch I used 3 SPST battery switches. It allows for all combinations. 

Pete

Thanks Pete and Phantom
I'll follow that link and look it over and get a copy of Calder's book. It looks like I'll need that book. ;)
I appreciate your info.

This link and my experience with house solar systems are why I use one combined bank.

http://www.smartgauge.co.uk/splitting.html (http://www.smartgauge.co.uk/splitting.html)

Batteries are more like sled dogs that are pulling Peukert's sled, you don't let two of the dogs ride the sled, while the other two pull.

Plus, it's pretty easy to tell if one is not pulling it's load...

How does one determine which individual battery in a combined bank of batteries is not pulling its load?

Dale

Dale, You asked the right question. After 30 years designing electronics, the aspect of  serviceability and testability are critical parameters. There is only one answer to your question. You disconnect the parallel banks and evaluate each banks performance under load individually. Manually switching banks in and out makes your system test simple and routine.

I've also spent 30 years learning how things explode and catch fire. Disconnecting battery banks from each other when not in use is a safety measure. A 100 Amp fuse on your battery banks may not prevent a fire in your absence. The same smart battery isolator on the alternator can be used for charging/floating from your shore power charger or solar charger. So you're covered.

Look, I think we all get the concept that capacity (total AH) of batteries connected in parallel add. If you are going for 16 hours between charge cycles you may need all that capacity. There are 2 ways to provide that. You can run one bank for 8 hours and the other for 8 hours  or connect them in parallel and do nothing for 16 hours.  The 8 hours each procedure has the added advantage. Assuming both batteries started with the same charge, the one with the lower voltage after 8 hours would be the weaker battery.

The solar industry is making conventional storage battery technology obsolete . The marine industry should take notice. The hot setup for a house bank IMO would be 6  Rolles Surrette 2 volt single cell AGM batteries connected in series (satisfying rule #1) . The smallest 2V battery they offer is 590 AH (68 lbs.) . This gives you 590 AH at 12V in one battery.  Pete

Pete,
Actually, I knew the answer to the question.  The point being is that it is not that easy to tell which battery in a bank or offending cell in a battery is bad and why design a system that suffers accordingly.

Didn't the telephone company of old use mega banks of low voltage batteries for their backup systems? As I recall they lasted forever as well.

Dale

Did either of you read the article I linked?

Yes...

For the most part the article was nothing more than a well written marketing piece directing the reader to the Smart Gauge.  It did contain factual information, much of which were stand alone facts unrelated to the stated conclusion that the Smart Gauge was the end all answer. 

Such as... It is well accepted that the sun is a truly 93 million miles away.  Experts agree that the surface temperature of the sun is 5000 deg C. Given these two facts, the only intelligent conclusion is you should be using the ACME air conditioner which offers superior comfort.

The lengthy sales pitch lists every conceivable short fall or negative possibility of every other system out there, of which most have been in reliable service for 30 years, while stating only the positive benefits of its own configuration.  The "article" focuses completely on why the smart gauge is better and Peukert conclusions are superior giving specific examples that don't necessarily state such.

Just because 100% of all people drink water each day and there 150,000 people that die each day, does not mean drinking water will kill you.

The Smart Gauge and Perkert may indeed be correct, but ignoring the issues associated with connecting large banks of batteries in parallel situations and ignoring how batteries fail is short sighted.

Dale

Hi:  I did read it, but I'll let Pete and Dale give you advice because they know more than I do. I did come across a discussion and some testing on the compass marine site that might be of interest.  http://www.pbase.com/mainecruising/smart_gauge. He also has some other info on electrical stuff. 

I don't know if I'd give Peukert a Noble prize for his work. But nice job curve fitting the charge/discharge inefficiency of a storage devices to that of a simple first order non-linearity, if indeed that's all that is actually going on in the physics of battery chemistry. As an Engineer I don't think I'd be so vain as to name the equation  after myself. Looks a lot like Euler's equation and we call that plagiarism.  

What the basic equation says is the efficiency of a battery can be gauged by the exponent K. In a perfect lossless battery K=1. In an AGM battery K=1.05. In a new flooded battery K is about 1.1. In an older sulphated flooded battery K gets up to 1.5 or more.

So in a conventional flooded battery, as K increases over time more energy is lost during discharge and the battery discharges faster. And to make matters worse, as the rate of discharge increases (current draw) so does the inefficiency. So even more energy is lost as heat. The battery goes non-linear or what is called a snowball effect. (exponential increase in inefficiency with current)

In regards to running banks in parallel or not it can make an insignificant difference in total capacity (AH) or it can make a huge difference depending upon the value of the exponent K. In an AGM battery where K=1.05. Discharging 2 banks connected in parallel gives you a 5% improvement in capacity. You will be able to go 45 minutes longer in 16 hours. Not much.

But if you have flooded batteries that are more than 1 year old, K can get up to 1.5 In this case, you can expect to get 40%less capacity by not running the batteries in parallel. Notice that I did not say 40% more capacity. There is nothing to be gained, your losses which are already high are simply lowered by running in parallel.

You can calculate all this for yourselves as I did using this online calculator.

http://www.batterystuff.com/kb/tools/calculator-for-load-specific-run-time.html

By entering the 20 and 100 hour AH rating from the manufacture it will calculate Peukerts value for K. You can also enter empirical values that you get from your own batteries. Then based on load it calculates AH capacity and run time.

Using this calculator, Two 100 AH AGMs running at 10 amps (5 A each) the total capacity is 210 AH. Individually there capacity would only be 100 AH each (200 AH total or 5% less)

Running the same simulation on two degraded 100 AH capacity flooded batteries (k=1.5) in parallel, my total combined capacity was only 117 AH (way down from the 210 AH out of the same sized AGMs) Individually it was a pitiful 41 AH (82 AH) combined by not running in parallel. Nothing to gain but plenty to loose. A wopping 143% loss in capacity from good batteries.

In summary, If your batteries are good (AGMs preferably) discharging in parallel makes little difference in capacity. If your batteries are old, running them in parallel will buy you some time before they go completely dead.

If I could buy into the theory, it says on good battery banks  where(k=1.05) you save 5% capacity each time you double the number of banks in parallel or each time you half the current. So 2 banks saves 5%, 4 banks save 10%, 8 banks in parallel saves 15%. A pretty silly  and expensive diminishing return.

My take away from this is, that there is a charge discharge non-linearity in batteries and one can benefit in various degrees by switching them in parallel during use (not during storage) and mostly that AGM batteries are superior to flooded . AGMs are 80-90% efficient in charge and discharge. Flooded only 40-60%. AGM will self discharge at 1-3%/mo, whereas flooded batteries self discharge at 20-40%/mo. AGM can be brought back from stone dead , flooded will be permanently degraded in a single deep discharge (K will be much greater than 1).


Good thread, I learned a lot. Thanks to all. Pete

I finally finished replacing the batteries, thanks to all on this group who offered their advice.
I ended up with the following system using four 6 volt golf cart batteries (US Battery US2200XC for $100 from local golf cart modification shop). The start battery is an existing 2 year old generic group 27 wet cell, ~800 CCA.

Key points:

• All charging sources go to the house bus bar
• If start battery dies, I put 1,2,both switch on both and on/off to off for starting the engine/generator
• If house battery dies, I move 1,2,both to 2 and leave on/off at on to use start battery for house, sparingly
• All house batteries are in same spot, bottom fwd of port cockpit locker

Thanks again. Now let's see what else breaks!! ;)
(http://i1278.photobucket.com/albums/y520/scherzoja/electrical/final1b_zps4e5faf60.jpg)

I like your system.  It places a lot of amps in the house bank and reserves a separate, appropriate, battery for starting purposes.  My system is identical...great minds, etc.

Jim

I've been watching this thread trying to bite my tongue and not comment, but everything I know and think I know screams for me to say something.
I design circuits to test circuits that charge and monitor batteries of all kinds. I do this for a living, so I know that everyone appears to be ignoring a vital parameter called self discharge.

Peukert did his tests when batteries and specifically lead-acid batteries were just a few decades old.
The real control factor in Peukert's formula is the series resistance caused the physics of lead, and the heat developed by drawing current through that resistance. Self discharge is partially the resistance of the electrolyte. Lead's bulk resistivity goes up as temp does, the electrolyte's bulk resistivity goes down as temp goes up. As you draw more current from the battery, more power is wasted in the series resistance of the lead, heating up the electrolyte, causing more self discharge.
One big reason it's not a good idea to permanently connect two banks in parallel is you are doubling the self discharge rate and wasting energy heating up the batteries: Both battery banks are effectively discharging through half the leakage resistance (they are now in parallel too).
It is done in the solar industry for the same reason it's done in the UPS industry. The batteries spend far more time charging than discharging, so self discharge isn't a problem.

In a new lead-acid cell self discharge is about 5% per month at room temperature. This rate goes up to about 20% at 40 degrees Celsius, and both the room temp discharge rate and the effect of temp increase with age until it becomes so excessive you believe the battery won't hold a charge, and replace it.

In older technology flooded cell lead-acids, the lead plates flake, fall in to the wells between plates, and reduce the distance through the electrolyte reducing resistance and increasing self discharge. In AGM and Gel cells, dendrites form with the same effect. As batteries age, series resistance and internal leakage go up. Accelerating this phenomenon is what you avoid by not paralleling your banks needlessly.

There, I feel better now.

Barry, does the fact that my batteries are topped up by the solar panels almost daily mitigate any of the self discharging effects?

And, what do you think about my shore charger mode that is is supposed to vibrate the scale off the lead (or whatever it actually does)?

Don't have the manual with me but there is a set interval that they recommend using that mode for one charge cycle, then it reverts to it's normal setting.

I too use (4) 6v golf cart batteries, with a separate dedicated starter battery.

The solar cells do reduce the effects of self discharge in newer batteries, but there is another issue I didn't go in to. The internal resistance from + to - goes down with both age and heat as I mentioned. Heat causes aging, and with one battery in worse condition than the other, the aging of the better battery is accelerated. Where that battery would have a negligible amount of self heating due to leakage currents, it is now feeding the weaker battery, developing more heat in the series resistance of both. Many high end UPS supplies have a load balancing circuit to keep this from happening. Some even sacrifice a few hundred millivolts to an isolator that keeps them from exchanging current. Newer isolator technology uses MOSFET transistors and a control circuit that has far less drop, so it will probably become a standard, but that industry tends to move slowly.
As for the shore charger, I don't think it vibrates the scale off the plates, that would only accelerate the process. It probably de-sulfates the battery. Lead-acid battery charges by creating ions within the sulfuric acid electrolyte. This causes sulfur ions to slowly become trapped in the surface of the lead plate, reducing the effective surface area, increasing the series resistance. De-sulfating actually increases battery life by reducing that series resistance I mentioned.

I think we'll soon be seeing Super/Ultra capacitor banks replacing some applications (Super Capacitor is trademarked, so Ultra is the generic term). I'm considering a bank for a starting battery. They are used in the railroad industry (charged by big diesel gensets) and some tractor-trailer rigs have them to be switched in parallel to a small starting battery before starting.
The benefit is that although they have much more ESR (effective series resistance) than a smaller capacitor, they have much less than a battery. Maxwell have an Ultra-capacitor block that fits in about a quarter the standard Series 31 battery space, has 2.1m Ohms of ESR and is 500 Farads with a 16V rating. 500 Farads That means if you charge it up to 14.5V (typical lead acid full charge) you can pull 160 Amps for about 3 seconds before it drops to 13.5V, and it can produce 2000A for a full second without damage. Their self discharge is around 170mA continuous not dependent on charge state. That sounds like a better alternative to a second battery in parallel, although at about $600.00 they are a little cost prohibitive today.  :o
By the way, they won't be completely replacing lead-acid, as this is only a 2 Amp-Hour solution (500 Farads X 14.5V/ 3600 Seconds), but in parallel with a lead-acid it takes all the surge currents that can cause heating.

Barrylab,

I kind of feel like you and I and Dale are arguing that smoking is bad for you to the tobacco industry. But I think you very effectively explain:

1. Why connecting batteries in parallel is simply bad for the life of your batteries.  You nailed this discussion and I recommend that we all  need to read it a few times for full comprehension.

2. How technology has moved us away from this (above) practice with very low on resistance high current power MOSFET smart battery isolators.

3. And that technology is addressing the need for better electrical storage cells beyond the lead-acid types. Super Capacitors and might I say Lithium-ion  have superb power densities and  charge-discharge performance approaching that of the super cap.

Thanks for chiming in.    Pete

Thanks for the kind words Pete, I wasn't sure if I came off as arrogant. When I don't know who I'm explaining something to, I have trouble with how deep to dive to explain something. Being an engineer by training and profession I have a sometimes violent reaction to marketing/sales belief systems that seem unsupported by physics, and need to scale it back a little. My friends know this button, and love to push it.

As for the lithium based batteries, they do have some very impressive characteristics, but still scare me some. I have a friend who is a dive instructor using them in a dive light. A few years ago he had a leak, and molten lithium (still burning) exited the bottom of his dive light at 70 feet. Hydrogen gas from Lead-Acid is dangerous, but molten lithium knows no bounds, and would go right through fiberglass. The charging circuits are pretty cool with all the safety features (current control & temp sensors) though, and some lithium technologies are 3 Volt cells instead of 1.4-1.6 like most other battery technologies. Fewer cells means less complexity and lower series resistance. I'm very risk averse (again the engineer thing), but I can see how they might have a future in the marine industry. (My friend still uses them in his new dive light!)
If you change the electrolyte, you have a super capacitor. Not a s much storage, 2.5V cells, but much safer aand still very low series resistance.

Here's a schematic that shows how I've wired my battery banks. I think this scheme incorporates all of the feedback presented by everyone in this thread. No battery banks are permanently connected in parallel, while all batteries receive charge and float via the smart battery isolator. Any or all banks can be selected to run the house or if need be the start bank can be paralleled up with the house to start the engine the engine.

(http://i1121.photobucket.com/albums/l505/banjoband/BatteriesShcema.png)

Not shown is the external smart regulator that controls the alternator field current. There is a sense wire from that device that goes to the pro-split-r. I also have a 3 way voltmeter select to monitor each bank.

I will next experiment with moving the Zantrex charge cable over to B+ input to the smart isolator. I will have to Diode Or the +12V to power the isolator from either the alternator or charger. I will also need to install a SPDT switch on this charge cable so I can select "Invert" and draw current from the House when in that mode or "Charge" when connected to shore power. In "Charge "mode all three batteries will receive charge and float current regardless of which battery bank(s) is supplying house current. Exactly what I think you need when the boat is unattended. Typically I will only leave one battery bank selected to run the bilge pump.

When I add a Solar Switching Regulator/charger I will also run that through the smart isolator in a similar manner as the Zantrex Charger/Inverter.

Pete

I could use some advice on charging systems.  One of this springs first projects is putting in a new 200AH AGM slimline battery from Mastervolt. We have our system split similar to Pete's with two golf cart batteries as our house bank, that are dead/dying and they are the ones that are getting replaced by the single 200 AH AGM.  (Got a screaming deal on one that was slightly damaged in shipping). It also may let us clean up the port locker some and get better engine access to change belts etc.

Unfortunately, our charger is probably original equipment, so wasn't designed with AGM batteries in mind and of course doesn't have a float feature.  It's probably part of why the existing bank is almost dead.  It also hums loud and doesn't have any state of charge info. 

I'm considering the Mastervolt power charger (http://www.westmarine.com/buy/mastervolt--power-charger-battery-chargers--P010976165)  in a 40 amp size, but there are obviously other options out there.  Three  questions:

1). If I set the charger for AGM will it overcharge our 12v flooded lead acid start battery?  ( the battery type setting on the Mastervolt is a dip switch for all three banks, same battery type).

2) Is 40 amp overkill, or is 20 enough?  We are in sort of binge sailing mode, curse of having a regular job, s o we plan on a week put away from the dock at an time with long periods of inactivity between. 
3) Is that a good charger, or are there better ones out there in the same basic price range? I mainly thought of it because it's the same brand as the battery, and they are available, but I don't have any other reason to choose this one over any other.   

I do not know of a battery charger that allows the user to select the type of battery for individual battery banks.  What this means is if you select the traditional wet lead acid battery and it was a 3 bank charger all three outputs would have the charge profile and voltage output curve.  In your case with your new AGM and your non AGM battery, one will receive the correct charge characteristics and the other will not.  Charles Industries at one time did make such an animal but I called them and they no longer produce that unit.

20 vrs 40 amps is a question of draw.  Because you state you are away from the dock for a week at a time, and then stay tied and on shore power for a few weeks, a small 10 or so amp would be just fine.  You have hundreds of hours to recharge before you shove off again.  Large amperage chargers are desirable when you sail all day and half the night using your precious power, tie up and plug in until morning and head out with the next tide.  Here you need to top off as fast as you can because your charging time is limited. 

As far as manufactures go there are many excellent choices out there.  Mastervolt is typically only known through West Marine. They are not a private label but damn near. 

I would like to suggest the following...

Purchase a quality charger that will satisfy the requirements of your new house AGM battery and dedicate that charger for that battery. Leave your old buzz box for your start battery.  Typically the start battery never gets that depleted as after the engine starts the alternator recharges the start battery on its own. 

When your start battery dies, replace that with an AGM and then tie both to the new charger and heave ho your old buzz box.

Have you considered an inverter/charger?  An inverter takes your ships 12 volt DC power and converts it to 120 volt AC power just like you have at home.  This means that you can operate a coffee pot, microwave or even plug in power tools while away from the dock.  Our favorite thing is making microwave popcorn while out sailing and watching the other boats reaction when they get a sniff. 

An inverter/charger goes the other way so to speak when you plug into shore power and the inverter then recharges the batteries power that it used.  You can purchase a nice Xantrex Freedom HF inverter/charger that will make 1000 watts at 120 VAC for $416 and a 1800 watt unit for $550.  They both feature three stage charging curves and charge at a rate of 20 & 40 amps accordingly.  These chargers are only single bank but you could add a cheap battery isolator and charge both banks at the same time. 

E-Mail me or call me with any questions or needed clarifications.  Here is the link to the Xantrex - http://www.xantrex.com/power-products/inverter-chargers/freedom-hf.aspx (http://www.xantrex.com/power-products/inverter-chargers/freedom-hf.aspx)

Dale Tanski

My boat came with an older model of Xantrex Freedom Inverter Charger. Its a standard old style 60Hz transformer rectifier design, meaning its heavy, has laminations that make a humming noise and is bulletproof compared to the modern designs  rely on high frequency AC line switchers and smaller lighter ferrite core transformers.

The other features I like is the built-in inverter and transfer switch. I recommend getting the remote front panel and installing that in the cabin. I relocated the actual unit to the starboard sail locker behind the water heater so I could not hear it humming. From the remote panel you can select invert to switch your AC outlets over to pure sine wave 60 Hz. Press invert again and they switch back to shore power. I wired all the circuits with the exception of the water heater to the AC output side of the Xantrex. The water heater remained on the AC input side. Very simple to wire up You will need a breaker for the AC output in addition the shore power AC input breaker.

If you scroll up to the 3 bank battery schematic you will see that I can select all or 1 or 2 banks for charging with the SPST bank switches. When I'm not at the boat I leave only one bank on. As far as mixed chemistry goes, I don't advise it. My start battery is AGM like the house batteries and my external smart regulator on the alternator is also set for AGM.

Pete

I installed a Xantrex Freedom Inverter/Charger when I got the boat.  It is a 2000 watt unit that runs our microwave and my wife's coffee maker nicely.  It weighs about 50 pounds.  In the charge mode it puts out 100 amps and has the selectors for wet/gel/AGM batteries.  I installed the basic remote which give you a nice insight into the battery condition, allows you control over the inverter function and you can limit your shore power amp draw.  I also installed a battery temperature sensor which throttles back the charge circuit if the battery temperature becomes too elevated.  One of the worst things you can do is over temp your batteries while charging.

It is indeed a workhorse.  Mine does not hum at all.  I also installed it where the factory hot water heater was located in the starboard locker.  The only noise it makes is when it is charging hard and the cooling fan runs.  I wired mine in to cover all of the AC circuits which includes the water heater.  I have on occasion, while motoring, run the HW heater which has a 1500 watt element.  My HW heater does not currently have the engine heat hooked up.  We have on occasion run a household box fan sitting in the companion way to ventilate the boat on a hot night while at anchor, or not on the shore power plug.  It has run the fan all night with minimal battery loss.

The auto shore power transfer switch works perfectly however there is a several second delay which is no big deal except the microwave clock is seldom correct.  I do not leave the inverter in the on mode when I leave the boat because if the shore power were to die, the inverter uses a small amount of battery power internally even in the idle mode. 

An inverter is like refrigeration, once you have that little item you don't want to live without one.  All of my batteries are AGM but I can understand due to the high cost, changing one bank over at a time. 

Dale

Thanks for all the info. After reading what you guys wrote, and doing some additional reading, I think it's best to say goodbye to our old flooded lead acid start battery.  It's the same age, at least I think, as the dead golf cart batteries, and while it hasn't failed me yet, I don't want to end up three fjords from civilization with bad weather coming and not able to start the engine.  Once you get one fjord over from Resurrection Bay, you can't get the coast guard on the VHF. I like to at least plan to be able to deal with most things myself anyway. You can always set off the EPIRB, but I wouldn't want to do that for a dead battery.  I would have to buy too much beer if I did that.  Plan B should never be "call the Coast Guard", that should be at least Plan F or G.

I think that means a new AGM start bat, but how big should I go?  The current one is a group 27, around 90 AH.  Strictly from a "fits the space" standpoint, I am considering another Mastervolt Slimline in either 150AH or 200AH, but that seems a little overkill for a start battery.  They are pricey, but little extra reserve capacity isn't a bad thing.  Any opinions?

I'm a little hesitant to add the extra complexity of an inverter.  I don't have anything we really need that runs on 110v power.  Our water heater is plumbed to take engine heat, or electric.  It seems extravagant to heat that with batteries.  Most of my boat tools are battery powered.  Recharging tools would be one use, but I do have a 750W portable inverter if I need it.  They are mostly charged at the dock anyway.  We heat with a Sigmarine Diesel heater that takes a little 12v power for the fuel pump.  A circulation fan is nice to run to even out the temperature in the corners, but that's 12 V as well. 

In my reading, there were quite a few very negative comments on the Xantrex charger and inverter, mainly about durability and support.  I always take them with a large chunk of salt, but there were several, and they were specific about their problems.  With electrical stuff, you never know if improper installation was why it stopped working.  Any insight if Xantrex is having quality issues?  In general, I prefer U.S. made where practical, and MasterVolt is, but I couldn't find where Xantrex was built.  I like the ability to remove the control panel and put it where you can see it conveniently.  I would prefer separate outputs for each battery bank, and I would also like the ability to use input power other than 110v 60 Hz.  The Mastervolt has both those features, but it's remote display isn't so great.  That means sticking your head in the locker to see what is going on with the charger.  Still a lot better than what we have now. 

I'm hoping that this installation will suffice when we eventually cast off and do some long distance trips, but I'm not opposed to adding an inverter at that point.  That might argue for going with the larger capacity charger though. 

An a related topic, our battery switch has a placard that essentially says start with the switch on both and don't change it while the engine is running.   Does anyone know why?  I was sort of assuming because you had a start battery, you would want to start with that battery.  That way you would know if it is Kaput.  If you never start with only the start battery, it could be dead for a long time and you are really starting with your house bank and not realizing you have a dead start battery, which, come to think of it, might be where we are.

One other tidbit of info.  According to the shop manual, the starter on the Perkins 108 has a max current draw of 900 amps.  The 200 amp hour AGM battery I am contemplating has Cold Cranking Amp Rating of 750 amps at 0F, and a Marine Cranking amp rating of 1,250 amps at 32F.  

That would seem to indicate that at 0F it wouldn't quite supply enough without help from the house bank. At the Marine cranking Amps temperature, should do fine.  The max draw is just the peak, so it might still be fine a few milliseconds after you hit the start button.  In addition, as the battery provides current, it heats up.  For us up here, the chances of wanting to start at a temperature of 32F or below are pretty good, but 0, the harbor is usually frozen over. Might not be quite the same issue down south where the palm trees aren't plastic.  

I've been buying case 31 size AGM batteries from Sears. Don't laugh. Their deep cycle marine battery as you expect is dubbed  the"Die Hard". It is actually manufactured by Odyssey.  Aside from making all the AGM batteries for the military they private label to Sears. Their AGMs are good to -40 degrees C and the 31 will provide well over 1000  cold cranking amps. Here's the link to the catalog.

http://www.odysseybattery.com/documents/US-ODY-TM-001_0411_000.pdf

I replaced a 27 frame sealed lead acid from West Marine with a 31 sized AGM and the increase in RPM at which I could crank was significant. I like the 31 because its the largest battery I can physically lift without a crane. Around 90 lbs. Typically cost $300 but goes on sale once and awhile. Sears gives me 6 months same as cash on them if you have a charge card.  Pete

Forgot to mention the issue with flooded batteries and cold is the freezing point of the electrolyte increases as the charge decreases.  Why I store my tractor batteries in the basement during winter. Might explain why your golf cart cells are dead or dying.

Thanks Pete.  After I read your link, I went back to the Mastervolt site and realized I made an error, so I corrected my post.  Their cold cranking amp rating was at 0F and Marine CCA is at 0C, (32F). I think that means I wouldn't have an issue cranking with either battery.  When I compare the Diehard/Odyessey it seems like either would work, but the Die hard is cheaper and has better Cold Cranking Amps, but lower total capacity in amp hours (100AH vs. 200), and I am going to have more of an issue with modifying the battery box.  As fate would have it, I was just installing a new Odessey spiral battery in the car this evening. 

In the end, shipping cost may be the decider, getting lead to Alaska costs.  I had one really negative experience with Sears not installing the cotter pins on my tie rods and loosing my steering at 65 mph, so I am not a big Sears fan.  It wasn't a disaster, but really scared me and the guy was arrogant and didn't take responsibility. 

First off I found this article and found it very informative regarding batteries. Worth the read...

http://www.yachtsurvey.com/boat_battery_basics.htm (http://www.yachtsurvey.com/boat_battery_basics.htm)

To answer the question of why it is a no-no to switch the battery selector switch while the engine is running, the answer is as follows.  There are several designs of battery selector switches.  The basic switch gives the ability to select one of two battery banks individually, a position to select both banks combined and an OFF position.  The issue becomes how the positions on the switch are configured and how the switch mechanically gets to those positions. 

If the switch is physically laid out so that while switching between banks of batteries and combining them (both position) the switch does not pass through the OFF position, that is a good thing.  While the engine is running and the alternator is turning generation power, if you disconnect the connection to the battery it can damage the alternators diodes.  A diode is an electrical device that does the same thing as a check valve in the plumbing world or a ratchet in the mechanics world.  It allows the flow of current (water for you plumbers, and spin direction for you mechanics) in one direction only. 

An alternator actually develops AC current (alternating current) when it is operating which is not compatible with your DC current (direct current) batteries.  By installing a set (4) of diodes in the output circuit of the alternator known as a diode bridge, the diodes modify the AC current into DC.  The problem occurs when you switch you battery selector switch to or through the OFF position.  The diodes see the disconnect as an infinite load.  Diodes are designed to handle a maximum load rating, much like each of us can only hold up so much weight.  If the weight was say instantly doubled, you would drop the load. In the case of the diodes, when the load heads towards infinity if even for an instant, the diodes drop dead. 

If the switch is laid out so that you pass through the OFF position while changing banks and the alternator is running, you kill your diodes.  Some switches are designed that way and some are not.  The next issue is how the switch contacts are designed inside the switch.  There are two types. One is a break before make and the other is make before break.  The first, break before make, means that the electrical circuit is disconnected to the load as the switch is physically moved before it connects to the next circuit.  The make before break means that the first circuit is maintained while the switch is physically moved to the next circuit. For a short moment of time, both circuits are connected before the first is disconnected and the second is left connected on its own.  This area where the both circuits are in play is the "both" position. 

You can check the design of your switch easily.  With the engine OFF and your cabin lights ON, slowly switch your battery selector from the 1 position to the 2 or perhaps your BOTH position. If the cabin lights dim or go off and then back on, your switch is a break before make and a diode eater.  If your lights stay on, your switch is a make before break and you can select what you want without damaging your alternators diodes as long as you do not select the OFF position.

If you find you are not happy with the design of your battery selector switch and you have the desire to upgrade, I would recommend looking into the Blue Sea line of switches.  They make several configurations of battery switches besides the standard 1 - OFF - 2 - BOTH.  Another great design feature is that they incorporate glow in the dark dials. Now this might not be such a desirable thing in the land where the sun never sets for half of the year, but for the rest of us it is nice to have the main switch easy to find in the dead of night.

As an aside... You have headed over a slippery slope.  Yes the design of the electrical system is very important. Yes the type of batteries are very important, but so is the proper selection of wire, connectors, buss bars and all the rest of the associated components.  Just like your missing cotter pins, if you miss even the slightest detail you may encounter an unanticipated outcome.  I would recommend solder on lugs for all of your battery cables.  Install fuses in your battery leads. Install covers and insulated partitions to protect against accidental short circuits.  A misplaced aluminum boat hook will cause big problems if it comes in contact with battery connections.  Wire gage is a huge factor.  Determining wire lengths for DC circuits is different than for AC wire circuits when allowing for voltage loss.  As you mentioned you are talking hundreds and hundreds of amps, too small of wire and think glowing wire like in your kitchen toaster.  Bigger is better is a great rule to live by while selecting components in an electrical system.  The sting of the shipping cost will quickly be forgotten while watching a burning boat. 

Dale

Thanks for the explanation of the reason for the switching prohibition, it makes sense now that you explain it. I assume I still have the internally regulated diode bridge inside the alternator, but to be honest, I'll have to check.  I'll do the test on the switch when I am at the boat next to see if it is the make-before-break type or not.  Even if it isn't a break-before-make, and as you put it, a diode eater, it seems like a good practice not to switch anyway, you never know when a bit of corrosion or grit could be in the contacts and cost you a diode bridge. 

Your point about wiring is well taken.  That's one of the reasons behind taking this on, it's currently a mess.  As an example, I have 9 wires off the common post of my start battery right now :o.   Those will go to a bus bar.  I also have some red wire on the common side of the system. You can tell Pete is an Engineer by his schematic, he lists the wire gages ;), that's really helpfull, although our setup won't be exactly like his so we may need to deviate some. 

That's part of the reason I'm researching this now to be honest.  Once I tear into it we'll be out of commission until the project is finished, so I want to have it as close to spec'ed out as I can before I start as I can so I can order the right parts. When he parts store is 300 + miles from the boat! planning is key.  That means starting with the capacities of stuff like the starter, charger etc, and sizing wire, fuses, buss bars from there.  Eventually, I'd like to end up with a schematic for the boat. 

We also have an anchor windless that needs power that I have to address.  Since we have to anchor deep, it's really almost a necessity.  I know some folks that use them as pot pullers for shrimp pots as well, and we might give that a try for fun, but it is a power pig, up to 60 amps at full load. 

I'm using a Sterling Pro Reg B external smart regulator on a Large Frame 100 Amp Ford Alternator. The regulator has a sense wire so over voltage is not an issue. If I switch it into an open it will shut down and issue an over voltage alarm. Somewhere around 16 VDC.

That being said, what it fails to provide is a means to fold back on over current. Initially I had a problem with the alternator belt slipping at around 60 amps. So I converted it to dual V belts.

(http://i1121.photobucket.com/albums/l505/banjoband/dualbelt.png)

Westerbeke wanted $630 for a dual pulley for the Westerbeke water pump. I was able to retrofit some small block Chevy hot-rod part on there for $18.00.  No more belt slippage. To test this system I ran the house batteries down and started the motor. Here's what happened when the Sterling Pro split R switched the  load to the dead house bank.

(http://i1121.photobucket.com/albums/l505/banjoband/prosplit.png)

I don't know what the actual alternator output current was before I shut it down but it would appear to have pegged that meter and bent the needle at well over 120 amps. I know the alternator got hot as a pistol in about 2 minutes. I have since replaced that meter with a 250 amp shunt and a high quality 250 amp meter movement.

I suppose this demonstrates why perhaps some don't recommend  switching battery load in while the alternator is running. With a proper alternator regulator it is not only possible but a necessary reqirement under normal operation.

So far I have only found one company with such a device that provides smart regulation and current fold back. That would be the Ample Energy V3 marine external regulator with adjustable current limit. So with that device I could switch in a dead battery bank without fear of taking out the alternator. I think you should be able to do that. Otherwise what good is it when you're out there with dead house batteries?

Incidentally I'm quite certain that its the single belt that allows the standard Westerbeke 55 amp alternator to current limit. At 55 amps the belt simply starts slipping thus limiting the current.

Also most 70 and 100 amp press in diodes can handle peak currents of over 200 amps and a PIV (peak inverse voltage of well over 100 volts. Its excess heat build up from forward IR drop that takes them out eventually. The harm in switching your batteries out while the alternator is running is it can take out your sensitive electronic gear. The alternator will most likely survive.

Pete

Ok, so this is long, sorry about that.  I'm recovering from knee surgery and using the time to plot boat projects. 

Pete's pimped out charging system got me thinking.  One of the goals I had in getting into the battery thing is to improve access to the alternator and port side of the engine.  (As you recall from our posts last year, the water pump access gave me fits).  It's a project or two into the future, but I am also thinking that upgrading our alternator would be nice down the road.  Eventually, we would like to go cruising, around 2020, or so, and current mods to the boat need to support that goal but let us sail and learn what we are doing in the mean time.  Our very limited experience would support what Pete said; at full engine RPM, our properly tensioned belt (at least as far as I can tell) slips.  I think we have a 55 amp alternator, but I'm not sure.   

So, how much horsepower can you get out of a single belted system, before you have to pimp it out like Pete?  If dual is good, would triple be better, what about modern automotive serpentine belts, and can you get a water pump pulley or crank pulley for those?  I tried to find some answers. 

An alternator's efficiency is about 60% according to the DelconRemy white paper at http://delcoremy.com/Documents/High-Efficiency-White-Paper.aspx.  (I found it to be a good read along with the battery site Dale recommended).

There are 746 wats in one HP.   Power in watts is volts x amps

A 55 amp alternator with an efficiency of 60% running at 14 V therefore requires:

(55 amps/.60)x14v=1283 watts

1283 watts/746 wats/hp=1.7 hp.  (what I currently need, and almost have, but it slips).

So if I wanted to hot rod the charger, how many belts would I need for say a 100 amp alternator, or a 150, or why not go for broke and do a 300?  More is better right?  Not so fast...... 
The book on my batteries says they can take 58 amps each max charging current, and not for the whole charging cycle, only in bulk charge mode and that is only for deep discharge that will toast your battery if you do it too often.  If it were divided evenly, that argues that there wouldn't be much point in anything over 116 amps, unless we were to put in a larger house bank at some point, and maybe that would be desirable. More is better right???

It seems like a water maker would eventually be nice, but it also adds a lot of draw, so it would be nice to be able to feed it without having to run a generator, if you have a big alternator and some inverter capacity to take up the start up surge for the motor.  Rich Boren, of RO water maker fame, says that works in his video, and he did it on a 365.  He says a Honda 2000 generator works well (not the knockoffs though). At 12v, 2000 watts is 166 amps.  (A little left over for charging etc, but it really only can sustain about 1600 watts.). That seems to argue for an alternator somewhere in the 200 amp range, pretty big. 

Here is where I got lost in the sizing.  Reading up on V belt stuff, I found out power transmission depends on a lot of factors, some of which I don't know. Some of them are:

Pulley material, aluminum is not as good as cast iron, but is lighter and easier to machine. 
Diameter of the pulley
Type of V belt, and there are a lot of options
Degrees of wrap
RPM
Type of load, I assume an alternator isn't too bad because at startup, the electromagnetic torque is low at low RPM and builds as RPM increases. 
Belt tension.
I tried to size belts using the charts I found to see how big you could go with a dual V belt, but struck out.  Maybe I need another beer. 

To me, experience trumps theory, so Pete's experience, and our limited experience, as well as a couple of other people speak up on blogs say that the limit of a single V belt on a Westerbeke is a little less than 55 amps.  So does that mean Pete's setup could go to 110, but would then slip?  When is it putting too much load on the bearings on the water pump and or crank?  Two belts doubles the bearing stress at least.  Are there other factors involved, are two belts twice as powerful as one?  The other question is, in practice, do cruisers need big alternators, or are solar panels and wind generators better choices?  Anyone have any real world advice for how big is big enough?  Is sizing it based on a water maker foolish to begin with?   

Any thoughts? 

P.S. Nice setup Pete. 

I wrote a response to this post the other day but hit the wrong button on the way to post and lost the whole kitten kabodle.  So here we go again...

I would strongly recommend that you indeed design your electrical system for the installation of a water maker if that is in the cards down the road.  If you design for what you have now and go to add the water maker at a later date it will only cost you more time and most importantly more money. 

When it comes to the V-belt drive that connects your alternator to your engine, there are many items to take into account.  You thankfully hit on many of them but I will try to elaborate.  There are design tables supplied by the manufactures of belt drives that will allow you to select the proper size belt cross section, the size of the pulleys (sheaves) for the selected ratio and if you know the dimensions between the shafts it will even supply you with the proper belt length. 

I have a very similar system to Pete's.  I turn a 110 amp Balmar marine alternator that has its own internal regulator, however I regulate the output using a separate stand alone smart regulator also made by Balmar.  One of the reasons is that the smart regulator does not load the engine for several seconds (programmable) which allows the engine to come up to operating temperature and RPM.  It also ramps up the charge rate so as not to shock the drive system. 

When I was designing the system I recall that a single belt drive was only good for around 50 amps.  This means that the average single belt drive arrangement can only transmit the amount of horsepower that is required by a 50 amp alternator.  By adding a 2nd belt I was able to effectively transmit the required horsepower to handle the 110 amp alternator. 

The sheave material that is utilized is somewhat important but only in marginally preforming drive systems.  Cast iron is the best material as it is a porous and thus has a higher coefficient of friction.  Aluminum tends to polish itself and the coefficient of friction drops as time goes on. 

The diameters of the sheaves are more important.  For the most part the larger in diameter the better as they provide more surface area for the belt to grip.  In my case I modified the diameters of the sheaves from the factory arrangement.  Diesel engines run relatively slow compared to their gasoline counterparts and we tend to run our diesels at lower RPM's seeking smoother quieter operation.  I designed an overdrive system where the alternator spins at higher RPM's than it normally would. In this step up ratio drive by installing a larger diameter crankshaft sheave the alternator spins at even more revolutions. 

Adding a second belt allows more HP transfer. The Perkins (modified for marine use by Westerbeke) has plenty of horse power to power all of your accessories.  Where the engine suffers is that to transfer that horsepower, there must be adequate belt tension.  Perkins put out a tech bulletin that warned about putting too much side load on the crankshaft. Excessive belt tension was causing crankshaft failure between the main journal bearings.  With every belt you add comes with it the tension of the belt.  Too much and you break your crank so I would stay away from more than two belts.

You mentioned a serpentine flat belt drive that are typically found on automobiles today.  Flat belts have much more surface area than a V-belt and they typically transmit more horse power and require less belt tension to achieve that transfer.  There is a company that produces serpentine belt drive systems for marine applications but they are pricey. 

Alternative energy for the most part is a looser.  What I mean by this is that solar for instance has the highest dollar for watt ratio out there.  I just got a quote for installing solar on the roof of the store to supply my electrical needs for lighting.  The quote came in at $102K. After state and federal incentives, my out of pocket expense would be $63K.  If you do the simple math it would take 15 years to pay this cost off if money cost nothing.  I figured out that the materials only cost $35k.  On top of that I would have to declare the government incentives as earned income.  NOBODY thinking from a return on investment would install that system. 

Wind turbines tend to be noisy and require maintenance. In both cases, solar and wind you have to wait for the wind or sun to provide while your food rots.  If you are going to be sailing I would recommend a aqua generator.  It is simply a generator with a propeller that you tow behind the boat that charges your batteries without noise.  The cleanest most cost effective energy source is your shore power plug.

Dale

D & D,
You asked for users actual experiences with the Beke, so here's ours:

We have 5 27series batteries for ~500 amp hours on the house bank.  Max charge when severely depleted is ~ 65 amps @ 1600 rpm. 
We have a 110amp Balmar alternator on a single belt.  We use Gates green stripe belts and they last about 400 hours before they start to slip.  I would not shell out for dual belts as the cost to advantage isn't worth the price. 
If I had a bigger bank, I would just throttle down for bulk charging to reduce the load on the alternator.   

The question is.... why is your 110 amp alternator only putting out ~65 amps? 

1) RPM not high enough?
2) Belt slipping?
3) Under sized wiring?
4) Regulator not set up or not correct?
5) Temperature sensor control on battery bank has a problem?

If I were to guess, I would say that the belt is slipping self regulating the output of the charging system.  At the 400 hour mark the belt begins slipping to the point that it is noticeable. I remember ~50 amps and D&D say 55 amps. It would no surprise me that the slip load on your alternator at the belt tension that you can maintain is 65 amps. 

My 110 amp alternator will put out 110 amps until the temperature sensor in the alternator throttles the system back to save the alternator or the battery temperature does the same.  Because I utilize AGM's the charge load is infinite. 

Dale

My thought is that the bank will only accept 65 amps max, even when depleted.  Anyone else want to weigh inmon this?  Flooded cell, 5 group 27 batteries.

Wayne

Wayne,
Everything Dale just said with the addition of  6) High internal resistance in the batteries. 7) your current meter is no good. Those automotive ammeters are crap.

I can only guess what's wrong as well. First thing is to get out the volt meter. Measure the voltage at the batteries before you do anything. Next measure the alternator voltage across the alternator with the motor reved up. I'd expect to see at least 13.8 volts. If the Balmar regulator is into some charge profile I would expect 14.5.

If that checks out, measure the voltage at the batteries. It should be within 3% of what you measured at the alternator. If not your wires gauge is too small. Per ABYC Standards, you should have AWG #2 in your 110 amp charging circuit from alternator terminal to battery bank . Don't forget the return ground directly to the alternator case ( not the engine block).

If it checks out get a  clamp on amp meter to verify what the current really is. Your should be using a quality meter with a calibrated shunt. Running wires to an from a panel mounted ammeter at 110 amps is a no-no.  If the current is low and the voltage is high, get your batteries tested for high internal resistance.

You can tell if the belt is slipping by looking at the engine tach.

If you voltage is low at the batteries make sure the sense wire to the balmar regulator is connected directly to the battery bank with its own wire. If you don't have a sense wire and or if you have diode isolators, that can render your charging system ineffective.

If you resolve something repeat the above exercise over as there may actually be multiple problems. And you may be looking at to some extent why I'm not that wild about wet cell batteries. They tend to be soft even when they are still considered good. Meaning the drop down when you load them and they float up when you charge them but they don't deliver or absorb much current. That's the high internal resistance.

Pete

(http://i845.photobucket.com/albums/ab16/daveanddella/Balmer%20100A%206%20Series%20Alternator%20Output_zpsgzbs1oae.png) (http://s845.photobucket.com/user/daveanddella/media/Balmer%20100A%206%20Series%20Alternator%20Output_zpsgzbs1oae.png.html)

I dug into the Balmar 6 series 100AMP 12V alternator and plotted the power output vs alternator RPM data.  (I used 100 Amp instead of 110 because they had data for it)  As you can see, there is a pretty significant difference between hot and cold.  The RPM of course makes a significant difference.  They offer several pulley options, single, double and serpentine, with a kit for the Perkins.  They recommend a double or serpentine over 100 Amps.  The combined effect of lowish RPM, and running hot, could explain a lot of the Wayne's missing amps.  Especially if you add in a little extra battery resistance and/or connection and cable resistance. 

Thanks Wayne, Pete and Dale. 

Wayne, by the numbers I was calculating that you would need somewhere close to 4 hours to recharge based on your post.  I figured a 50% discharge, so 250 amp hours at 65 amps, with about a 10% loss in the system.  At 1,600 rpm, I would guess the Beke would burn a little over a gallon in that time.  Is that the way it really works or does the charge rate drop off as the battery fills up?  (Nice post on your web site about going through the canal!)

Are you using solar, wind or water power to supplement your power needs?  I read that you had some solar.  How much does that help out in practice? 

At what point would it be better to just use something like a Honda 2000 generator, and save the fuel and wear and tear on the Westerbeke?  A Honda could put out 1600 watts at 13v so about 120 amps, or roughly double what my alternator could do, and use less than half the fuel. The downside as I see it is weight, and you would have to carry gas or do a propane conversion. Upside is they are quiet, and only half the time listening to an engine, plus flexibility.  Some people have safety concerns about using them underway, but it sounds like a lot of people do it at anchor. 

Dale, I was reading about the water generators, and it sounds like they work, but you can loose then to marine life, or trash, and they have some maintenance issues too. They also don't work if you aren't moving, so if you are anchored, no power.  Do you know how practical they are in real life?  There is a lot out there on the strengths and weaknesses of solar and wind, but less on water generators. 

I was reading the Westerbeke manual, and one option in the book is to add another alternator, doubling the capacity, by adding another alternator instead of installing a single larger one. The voltage regulator would have to change, but the company Pete mentioned makes one that can handle two alternators, and I think Balmer does according to their web site.   Because the extra alternator is on the other side of the engine, some part of belt load would cancel the first, alleviating the crankshaft stress some.  That would put it on the Starboard side, and space would be an issue, on Polaris it's already crowded there with exhaust plumbing and the raw water pump. Has anyone out there done a second alternator?

On Pete's post, you mentioned that you could tell by the TAC if the belt was slipping, was that because the tac is alternator driven, so if it slips, the rpm shown doesn't rise like you hear from listening to the engine?  I could tell by smell and squeal, I was too distracted to pay attention to the TAC. It could have been slipping a bit at lower RPM, I just didn't notice.   (We're still figuring this out, sorry if that's an obvious question).

D&D,

I love your analysis on Wayne's issue.  Numbers and data are a wonderful thing.  The charge rate does indeed drop off somewhat as the battery achieves a higher charge so your calculations would have to be adjusted not in Wayne's favor. 

There are not many people out there that use water generators.  For that reason you will not find much informational feedback by actual users.  You are correct that marine life have been known to feed upon them and blades have been lost from impact with debris.  Wind turbines loose blades and solar panels find there way behind obstructions limiting their output.  Everything has its limitations.

There is a unit that mounts on the stern much like an outboard motor. Instead of towing behind on a cord the generator is held under the surface of the water by a bracket.  When not required or not in use, the unit can be removed from the water. This close proximity to the boat provides added protection to the equipment.  Some would argue that the efficiency is less due to turbulence off of the hull and others would argue that it would be increased as the water flowing around the keel assembly actually increases its performance.  Either way it is yet another option while underway.  You are correct when at anchor it is not paying its way.  You may benefit from it while on the hook and the tide is flowing.  For me in Lake Erie not so much. 

Your idea of a second alternator is a good one.  Where it gets complicated is when you already have additional engine accessories like a refrigeration compressor.  It even gets better if you consider the redundancy factor.  Two is better than one especially off shore.  Yes there is added weight, yes there are more moving parts but all in all the advantages of having two alternators when well outside of a spare part facility is a good one. 

Dale

So why would anyone pay $1000 for a 110 Amp Balmar alternator when you can buy a 100 amp Ford Alternator for $100. The hands down answer is: "ding ding ding"..  Because its got 12 poles.

In the marine diesel environment you want to be able to charge your batteries with the engine running slightly off idle. At least that seems ideal to me. The reason why most alternators aren't up to the task is they are only 8 poles. You can count the claws on the rotor to determine how many poles your alternator has.

Here's a plot of your typical automotive 8 pole alternator.
(http://i1121.photobucket.com/albums/l505/banjoband/10si20perf20curves_4001.jpg)

Figuring a pulley ratio of around 2.5:1 means my engine needs to run at 1800 rpm to get the alternator output up on the curve at 4500 rpm.  However with the 12 pole Balmar running at the same ratio,  per Dave's chart,  I'm up on the output curve  at only 1000 rpm engine speed. 33% better as you can calculate comparing 12 poles to 8.

As for alternative energy onboard. Below 25 degrees latitude solar is the most popular choice. 100% of the cruisers have some form of solar as the primary energy source.  I had a wind turbine on my mizzen and I took it down. Up in Alaska I'm not sure if solar is a good way to go. As I learned in the Satellite business, the look angles up there are very low and likewise tracking the sun sounds problematic. But there are times of the year when you get lots of sun. Look for mono-crystalline silicon panels. They are more efficient and require less space than polycrystalline. Make sure you get a high efficiency PPT (peak power transfer) charge controller inverter that can handle the high open circuit voltages of  your solar array. In my case I'm looking at running 2 panels in series which puts me up around 50 volts .

Pete

Another reason for buying the Balmar is that when you take one apart you will find that all of the innards are coated which means that as it draws all of that salt air through the case with its cooling fan, the salt will not dissolve the parts.

Dale

On the compass marine site, he has an article on rebuilding a Westerbeke alternator, which I think is what we have, and it shows the rotor.   http://www.pbase.com/mainecruising/alternator_rebuild&page=1.   

So Pete, want to guess how many poles?   You got it, looks like 8, not 12, although it's hard to count accurately in the pictures.  That would mean that it's charging curve would require a higher RPM.   Assuming I have something like a 2.5:1 pulley ratio that would mean I would be getting something like 2/3 to 3/4 rated output at 1600 engine RPM.  Maybe 30-40 amps unless it's limited by the battery, lead wire resistance, or regulator. 

I also read a while ago on one of Dale's posts that he couldn't connect his TAC, is that just that it would read high by 12/8 because it picks up the pulse off the poles to count RPM, or is there something else related to the Balmar?   
This is getting to be a pretty deep string....   

Thanks for the inputs guys,

Rpm doesn't seem to be a factor as revving the engine does not increase amps past 1800 rpms
I definitely know when the belt is slipping as it squeals like a pig.  The big problem with single belts are that belt life is not long.
Wiring is single aught cable, should be enough.  It never gets warm to touch.
I have a Balmar regulator, pretty sure it is set up right.  Jumpered to flooded cells.
I don't have a temp sensor.
Ammeter is a shunted LinkLite meter.  (Nice unit BTW, if anyone is looking for a battery monitor)

I am actually pretty happy with 65 amps for the batteries I have.  Even depleted, it takes about an hour before the amps start to ramp down so I don't think it makes that much difference.

Just for anybodies interest in systems for cruising:  We have 200 watts of solar on a tilt mount between the davits.  It supplies about half of our needs.  Wish I had more, perhaps on the bimini even though I would have to deal with a lot of shading from the mizzen.
We have a Honda 2000 and a 45 amp battery charger that we use at anchor to bulk charge batteries in the morning, then let the solar panels float the batteries up to full charge during the day.  We also charge up computers, tablets, the vaccuum and make water while its running.
We only run the engine for battery charging while on passage. the instruments and autopilot really run up our power consumption.  I have used the Honda under way before, but don't like the smell or trying to pour gasoline into while the boat is pitching wildly.

Quote from: Maruska on February 17, 2015, 08:13:17 AM
The question is.... why is your 110 amp alternator only putting out ~65 amps? 

1) RPM not high enough?
2) Belt slipping?
3) Under sized wiring?
4) Regulator not set up or not correct?
5) Temperature sensor control on battery bank has a problem?

If I were to guess, I would say that the belt is slipping self regulating the output of the charging system.  At the 400 hour mark the belt begins slipping to the point that it is noticeable. I remember ~50 amps and D&D say 55 amps. It would no surprise me that the slip load on your alternator at the belt tension that you can maintain is 65 amps. 

My 110 amp alternator will put out 110 amps until the temperature sensor in the alternator throttles the system back to save the alternator or the battery temperature does the same.  Because I utilize AGM's the charge load is infinite. 

Dale

To quote Pete...

Why is it?

Dale

Enjoy the next passage Wayne, send pictures of the Galapagos when you get there. 

On the Solar, do the panels interfere with getting in and out of the dingy over the stern?  We have the Forespar Davits, and eventually when we head out, we were thinking that would be a good spot for solar panels, but we're wondering about getting over the rail, under the panels etc. Do you have a cutout in your stern rail?  Solar isn't easy up here, for reasons Pete alluded to, except for keeping up with battery discharge, and we have shore power for that presently.  When we head out, that will change.  It seems like from the locals, flexibility in your mounting arrangement is key to making it work in high latitudes. 

I have read some people that are concerned about using portable generators like the Honda from a safety standpoint.  It seems like if you are carefull and not use it under way like you said, the risk of fuel spills, CO poisoning and electrocution  could be fairly easily managed.  What do you do in practice? We're curious about when you feel like you can use it and where you put it in use, and not in use.  What do you do to store gas, or did you do a propane conversion? 

Wayne,
If I had that high end alternator I don't think I would be happy with 65 amps. And all that squealing. As the locals say out here in southern California,  Dude...

I understand not wanting the expense of converting to dual belts. Westerbeke wants $600 for a dual water pump pulley. Perhaps a nice belt tensioner would help.

This is being offered on EBay as "Delorean Belt Tensioner" . Its  304 SS and costs $44.

(http://i1121.photobucket.com/albums/l505/banjoband/tensioner_1.jpg)

When I got to upgrading to 2 dual belts I did the cross reference and found that in my case the correct belts were actually metric. Sort of makes sense since my Westerbeke is a Mazda. My points is and Dale pointed this out awhile back that there is more to V belts than just the length. The V needs to match the groove angle without bottoming out on the pulleys. Otherwise they slip and squeal. What was on my motor was totally wrong.

Pete

Pete,
That looks like a sweet set up I would love to have!  As of now, I jam a hammer haft between alt and eng block to try to adjust belt tension with one hand and try to tighten the bolt with the other.  Complete pain in the ass.  I'll look at this again when we are in New Zealand and have some time on our hands. It only squeals to let me know to tension it again, like a puppy that needs to go out. I have 4 new belts as spares this trip.
As far as 65 amps out of my alternator, well, lets just say that I am having enough problems with systems that are totally failing this year that I relish the ones that actually work.   Boat work in exotic places anyone?  ;)

D&D,
Yeah, the panel is totally in the way of the davits.  No gate.  We drop the dingy, raise the panel out of the way with a rope sling over the mizzen boom, I climb over the rail, duck under the panel and drop down into the dingy monkey style, then use the side rails to board and debark every time we use it.  No system is perfect, but as long as I am young and limber(53 years old! Arrrgh!) I can deal with it.  We met a Pearson owner (not on this forum) whose son was a boat stainless welder last year in Georgetown Bahamas.  He had a system I was totally jealous of, including an opening gate in his pushpit.  He actually raised his mizzen boom a few inches to give him a totally enclosed cockpit with 7' headroom.  Sweet set up.  If you have a few extra grand, I highly recommend it.  lol.

Thanks D&D,
Pics from the Galapagos will surely be up on Dana's web site when we get there.  Probably 2 weeks from now.

For the Honda, I run it in the cockpit, lashed to the rail so it wont tip over.  When not in use I stow it in the lazzerette with padding around it to keep it upright and stable.  It has a closable vent in the fuel cap so and the off switch shuts off the fuel so I don't worry about it spilling there. The Honda just sips at the gas so 10 gals in jerry jugs keeps us going for a month or so for that and dingy engine usage. 

I have  a dream of installing a 26 gal gas tank aft of the rudder post under the propane locker some day.  Direct connection to the Honda via the remote tank connection that Honda sells.  And a small pump to refuel my dingy engine via a hose and petcock.  No more gas cans cluttering my rail is a very sweet dream.

Now if I can only get Dana to get rid of the kayak on the rail too..... ah well, the things we do for the Admiral right?

Quote from: Della and Dave on February 23, 2015, 10:27:28 AM
Enjoy the next passage Wayne, send pictures of the Galapagos when you get there. 

On the Solar, do the panels interfere with getting in and out of the dingy over the stern?  We have the Forespar Davits, and eventually when we head out, we were thinking that would be a good spot for solar panels, but we're wondering about getting over the rail, under the panels etc. Do you have a cutout in your stern rail?  Solar isn't easy up here, for reasons Pete alluded to, except for keeping up with battery discharge, and we have shore power for that presently.  When we head out, that will change.  It seems like from the locals, flexibility in your mounting arrangement is key to making it work in high latitudes. 

I have read some people that are concerned about using portable generators like the Honda from a safety standpoint.  It seems like if you are carefull and not use it under way like you said, the risk of fuel spills, CO poisoning and electrocution  could be fairly easily managed.  What do you do in practice? We're curious about when you feel like you can use it and where you put it in use, and not in use.  What do you do to store gas, or did you do a propane conversion? 

Can you guys explain what the best practice is for common vs. ground wire?  The context is the battery charger wiring at first, but I'd like to understand it better in general.  I'm planning my wiring and I think I am going to get at least a common buss from this outfit online called Obersheiner's sailing supply;-). They seem to be pretty reliable and the owner knows the Pearson 365 really well.   http://obersheimers.com/categories/electrical/busbars-connectors-insulators/blue-sea-systems.html?sort=featured&page=1. I may collect positive as well, but that isn't as big an issue on the battery terminals, and I need to figure out how and where to fuse them first. I think currently the first fuse the positive current sees is the main breaker in the DC panel.  Sizing advice appreciated here.....

I am planning on collecting my common terminals on the buss bar instead of the current mess on the start battery terminal.   The negative pole of both batteries will go to the common bus bar using 2/0 cable.  This bus bar is rated at 250 amps, about the biggest I could find, but my start current surge will be above that, even if it is for a very short time.  Planning on the heavy cable from start bat and to starter being ganged on the same stud if that is feasible. 

My new mastervolt 40amp battery charger has a common and a ground.  I went for it because it could accommodate 40 amps on 3 separate battery banks, provided a float and battery temp monitoring and was selectable for type, AGM for me.  I have a bunch of green wires connecting all the through hulls etc, I assume that is "ground".   Do I connect the green ground from the charger to them, and the negative/common  to my new common buss bar?  Should I connect common and ground, or is that a marine no-no due to stray current issues?

P.S. I leave the battery switch in the off position when we leave the boat, but the bilge pump bypasses the switch, so the bilge pump will still operate. I am hoping to leave the charger on too to allow shore power to float the banks, unless this is stupid for some reason.  We also leave a small120v AC electric heater/drier running.    Helps to keep any water in the bilge from freezing. 

Before I say anything you should read this paper:

http://www.qualitymarineservices.net/Neutral-Ground%20Bond,%20Exchange%20Article,%2012-2005.pdf

My boat has 6 separate buss bars.  AC ground (green/yellow), DC ground return (black), Bonding system Ground (green), RF Ground, and the AC neutral buss (white) and a  +12 V buss bar .

On my boat they are all wired to individual junction buss bars. I can measure high resistance between AC ground, and DC Ground.  Since the engine block is connecter to a propeller shaft,  DC ground and bonding system cannot be isolated from each other easily.  That being said, I have a single wire connecting AC ground to DC ground, DC ground to the  Bonding system Ground, and RF ground to Bonding system.

There must be no connection  ever between neutral buss and AC ground onboard when running on shore power. As the paper explains, this is done only at the source.  Its important to check for unwanted connections between AC ground and neutral shipboard. This can be tested with an ohm meter with the shore power removed.  If you have a charger inverter the IEC required that the inverter make that connection between ground and neutral at the source which is now the inverter. A properly designed crossover switch will float the shore neutral at the input but connect it to AC ground at the output. The isolation of the inverter prevents this from becoming a hazard to swimmers.

For obvious reason your galvanic isolator goes in series with the AC ground from the shore power socket. With your bonding system connected to shore power the galvanic isolator will keep your zincs from protecting you  neighbors and everyone else in the marina at your expense.

The 12V buss bar has a main 50A breaker emergency. Everything in the house although fused and switched separately goes through goes through that one breaker. Its the one I pull if there is an electrical fire.


Pete

I was hoping Pete would hop in on this one but he only provided the highlights.  I will read the article he supplied and that might provide the details.  This issue is a Pandora's box even in the best of boat yards and builders sheds.  You have opened a mother load of questions.

Dale

Dale,
You are certainly right on that . Bonding and grounding techniques have become a very contentious issue. By now I have read and heard all the arguments. And some of the alternate views on this topic come from people in the industry that I have a great deal of respect for.

These views all seem to stem from the singular goal of avoiding electrolysis. I don't know if its the price of zinc or the misguided opinion that electrical standards are a form of gubment interference. I have been told to simply cut all my bonding wires off and do not connect any ground to any other ground. I was told the worst thing you can do is put a underwater bonding plate on the hull. I was told of a lightning strike blowing that plate off and sinking the boat in under a minute. The argument is that bonding systems attract lightning. When I told him he would need a ground for his SSB radio he told me he needed an antenna that required no ground. I steered him to an antenna balun that would accomplish this.

Despite the best efforts to isolate, the prop and engine on any boat is bonded to the water, and the DC ground is connected to this bonding system. The AC ground on the TV, refrigerator and microwave is floating, but what he doesn't know is that the neutral is bonded to the AC ground back at the transformer on the dock. A short from line to case on these appliances will pop the breaker thanks to the electrical standards.

The thing about electrical standards is they are the rules everyone connected to the electrical grid needs to follow for them to be effective in preventing electrocution. Bottom line for me is any hunk of metal on this boat that is not a UL approved appliance could now be connected to the 110VAC line and nothing would happened until some innocent person grabs it. Like the diver that cleans his prop. The entire 12VDC system could now be sitting at 110 VAC and everything would still be working until you touch the UHF radio and the microwave at the same time. Lightning striking the antenna would find a path through the 12 system in the boat, fry everything connected to it on its way to the propeller and probably set the boat on fire because of the insufficient gauge of wire. (Factoid: Soldered lugs in bonding systems should be avoided because a lighting strike will melt the solder.)

And I would not want to be near any chain plate down below in an electrical storm. With no clear path to ground dissipate even normal static electricity, an actual lightning strike would turn that main salon into a fire storm.

With all due respect to all the shipwrights that are first rate carpenters and riggers and such that say they know better, I'm sticking with what the IEC, ABYC standards says to do. Its my expert opinion as well and I believe I have the creds to say that.  You know I might want to get a marine survey or a USCG courtesy inspection someday. The best advice I can give for electrolysis is get a galvanic isolator.

Pete

Never ask a question you really don't want the answer to.  Pete turned Pandora's box inside out with this one.  Without question, an excellent set of answers/opinions to the thorny issue known as marine bonding/grounding. 

In summary, it would appear Pete believes in a separate ground system for your 12 volt system (negative side of the battery) A separate system for any metallic item above and below the water line that is not a typical conductor complete with external bonding plate.  A separate system for 120 VAC ground and a system for 120 VAC neutral.

Where it gets screwy is that the engine, V-drive, transmission and prop shaft would typically be considered a non-typical conductor except that the engine itself is connected to the negative side of the 12 volt battery system through the starter circuit.  This means that now the 12 volt dc system is attached to the stand alone ships bonding system. 

The same thing can be said about an appliance such as a battery charger. It is supplied by 120 VAC and converts that to  12 VDC.  In that magic box the 120 VAC ground (green or non-insulated wire) could be connected to the 12 VDC negative side through a component in the box.  This would mean that the 120 VAC ground is now connected to the 12 VDC system which is connected to the ships bonding system. 

My boat is wired very similar to Pete's except I do not directly/intentionally connect the AC to the DC system.  I also tore out all of the copper foil from the past owner/owners SSB equipment.  In short I think we are both right...

Dale

Dale,
I'm not sure you got my understanding correctly. My last post was an example of how not to do it. It was how an "expert" told me I should do it. I go on to describe the sequence of disasters that could result.

I run separate ground busses so I know what all those wire are, Bonding,  DC ground,  AC ground. I believe it came that way from Pearson. But I absolutely do tie them all together with one heavy gauge wire. That's in agreement with the ABYC standards.

The reason I tie them together with one wire is so that I have a single point failure in event of a huge fault current.  I want this connection to be deliberate and to be ale to point out the exact wire that makes it a certainty. An inadvertent connection between ground systems caused by  some other appliance which is redundant is OK,  but it goes away if you take that appliance out of service. Now you introduced a danger.

I would never recommend that you intentionally try to keep these grounds isolated from each other. Its not safe.

Pete

Wow, that was Pandora's box, sorry about cracking the lid:-)  Actually, thanks a lot, I just learned a lot.  I think I see why it's a controversial topic, depending on what you are trying to protect against, it might result in a different "correct" way to wire it.  It took me a while to read the article, it's pretty well written, but dense, then I went to Don Casey's book, and read much of it again.  Casey says "To reduce the risk to swimmers, the green wire should be connected to the ground terminal on the engine." Since, as Pete mentioned, the DC neutral is connected to the engine, the AC ground and the DC neutral would be at the same potential, i.e. connected.  Casey's book clearly tells you how to check. 

Captain Rifkin in the Article says "The ABYC standards and the National Electric Code are consistent when they require that the neutral and ground only be connected at a “newly derived source.” In our case, this means that the connection is made at the Marina's electrical service entrance (which is a transformer ashore) " So it's connected, but not on the boat.  Then he goes on to explain for inverters and gensets you need to connect them. Because they are "newly derived sources". 

Casey essentially says connect at the engine, and Rifkin says on the dock, but which changes with inverters or generators. I agree with Pete, the best plan is to at least try to follow ABYC. 

So applying this to my situation, on my battery charger, I have the AC input cable with three wires.  I'm figuring they just go to the AC bus feed marked charger, assuming the breaker has the capacity, if not, upgrade.  The AC charger ground goes to AC ground, if I can find where that is.  I also have what I think is the DC ground, on the DC output.  I can either connect that to the engine block, or a grounding buss then to the block, or connect it to the AC ground for the shore power ground.  If I understand Pete correctly, the best thing, and ABYC thing, to do is collect this to the grounding buss, then connect that to the engine.   Did I understand that right? 

The other thing are our green bonding wires.  I don't think we have a galvanic isolator, but I am not sure I would recognize one if it bit me on the bum. I assume the galvanic isolator connects in series to the ground wire on the back of the shore power plug.   The bonding wires from the through hulls, chain plates etc, should go to a buss, then to the engine block grounding stud.

I have read the about whether or not to ground the through hulls.  One opinion is that grounding promotes lightning currents, which could blow the fitting out, leaving you with a hole in the bottom of the boat.  The counter argument is that corrosion can be countered by grounding to the prop shaft zinc, so you should bond them. For Polaris, I am inclined to bond them because lightning is pretty rare up here, so corrosion is the bigger threat.  If we sail south, at some latitude that would change, and the bigger risk might be lightning.   Beth Leonard's article on the other string seems to support that, as Alaska didn't even make the map. 

We do occasionally get thundersnow, but it's very rare and I have never heard of a boat getting hit. 

Did I understand this correctly? 

The statement in a previous post that, "The best advice I can give for electrolysis is get a galvanic isolator.", was not completely accurate.  The best thing you can do to isolate the shore power is to use an isolation transformer.  An isolation transformer breaks the shore connection completely by transferring the power through a magnetic field.  The so called galvanic isolators sold for marine use don't actually "isolate" you from anything.  They do block DC stray current through the diode used in the circuit, but they do not block AC current.
Galvanic isolators are prone to failure and most of them on the market have no indicator to tell you they have failed.  You may have one installed thinking you are blocking DC current and in reality it may have failed months ago.  The only ones approved by ABYC are the ones with an indicator that shows it has failed, these typically run around $300.00 or more.  Galvanic isolators also do nothing to protect from electrical shock.  AC stray currents in the water around boats at docks kill people every year.  Galvanic isolators do nothing to prevent this.  Only isolation transformers block both DC and AC currents and protects from shock hazards.  If you truly want to have the safest system on your boat and extend the life of your zincs, then install an isolation transformer not a galvanic isolator.

Lou,

I have an isolation transformer and the only reason I have not dragged it down to the boat and wired it in  is that it weights 50 lbs. I will agree with you 100% that an isolation transformer goes a long way in preventing electrocution in and around your boat because it allows you to permanently establish the bond between isolated  neutral and the AC ground buss once and for all at the secondary winding of the transformer (the newly derived source ) located on your boat. With some of the screwed up wiring that I have seen in marinas its might be too much to expect that those connection are too be trusted to be made at with the transformer on the dock. The isolation transformer will protect you from that.

But based on some of the schematics that I've seen for marine isolation transformers I would not go so far to say that all of them isolate you from the shore power AC ground. There are ground connections to the transformer core primary and secondary. Without checking it with an ohm meter there is a good chance that because of IEC requirements you will remain connected to AC shore ground, in which case you will still need a galvanic isolator.

A truly isolated high voltage AC system that is not bonded to a solid earth connection is dangerous.  At a minimum it needs to be tied to the boats underwater bonding system to establish a safe reference between you and the other boats around you that don't have an isolation transformer and are also connected to shore ground.

Pete