The 6-12V batteries are arranged in two banks of 3 each, with a total of 300 amp hours of rated capacity in each of the banks. These are the house/engine starting batteries. The 2-6V batteries are connected in series to serve two other purposes:
- Generator starter battery bank
- Windlass battery bank
But I digress. This weekend, I crawled down in the bilge with a gallon of distilled water (always use distilled water - you don't want the minerals in tap water to foul up the chemistry) and topped up the batteries. Tho none of the cells was particularly low, a total of 2/3 of a gallon of water was gone when I climbed back out of the bilge. Those 8 batteries have a combined total of 42 cells, and even a little water added to each adds up to quite a bit altogether.