High output alternator/controller

[Risto and Liz]

I am slowly working my way through the the systems on Silver Wings (hull#14 formerly Sol, p-367). I am trying to understand how if I can adjust the output from the alternator. We have a two battery main bank of 430aH, a 100amp alternator with a xantrex XAR regulator. On the multi-day trips that we take, I find that after a couple days main bank gets down to -50-60aH (refrigeration) and even with several hours of motoring the each day it may get down to -25aH. I have watched the regulator and it cycles between 'bulk' and 'float' but not charge the bank to 100%. Is there some adjustment that I should make? It seems that a 100 amp alternator souls charge faster that it does. Is it a matter of battery acceptance rate?
I admit to being on the learning  side of the curve when it comes to electrical but I do want to learn. Leo (PO) did an awesome job rewiring and setting up the new batteries. I just need y'all's help to understand it all.
Thanks!

[Leo]

Hi Risto,

In the past I could see 60-70 amps from the alternator at the link battery monitor after a day or two sailing. If your not seeing that check the fuse on the alternator output terminal. Also the batteries have fuses. The instructions and set up info for the Xantrex regulator should be on board but if not you can find them online. It's adjusted with a magnet to set the switches.
The alternator charging system is pretty simple. alternator wired to the battery plant and an echo charger to the start battery.
Check all fuses and cables
regulator working?
alternator output?
If I think of anything I missed I'll get back to you.

Len

[barrylab]

Your charge controller is trying to protect your batteries. Batteries have internal resistance that causes them to heat as they charge. The resistance and the internal leakage goes up as they age, and the aging is caused by the heat. When you approach a full charge condition, the battery will accept less current without heating. This link might help:
http://batteryuniversity.com/learn/article/how_heat_and_harsh_loading_reduces_battery_life