As the boat is in the midst of construction, I did not want to spend money on new batteries that will sit for a few years before they get used "in production".
Small-boat to the rescue
Our little 28 footer has four 6volt "golf cart" style batteries wired as a 12volt house bank. Despite being eight years old, the battery testers (hydrometer and electronic) have always tested these as "good". Which, for us, is almost unheard of. Seems we always hear of boaters having to replace bad batteries every couple years, due to, if anything... age. We experienced the same until we upgraded to a more modern charging system (Balmar alternator & three stage regulator) ten years ago. Side note: I am convinced that with modern three-stage charging systems and proper maintenance (keeping electrolyte levels up and never discharging more than 50%), deep-cycle flooded cell batteries can last almost indefinitely. Anyway, I figured if I had to buy new batteries, it would be for the small boat, which would reap most benefit, and the old ones would be transplanted into the Westsail.
|Tailgate party: top-up and test of batteries.|
|Batteries installed and wired in series to form a 24volt bank, 245 amp-hour capacity (125 useable).|
To give an idea of how many more batteries we can fit, this last picture shows the remaining space in the box. We can fit at least eight more of these golf-cart type batteries, which would give a total capacity of 735 amp-hours (367 amp-hours useable) and 780 lbs of more ballast!. For 24volts that is a LOT of reserve capacity. Should we ever fit out with more modern, higher power density batteries (like lithium), add the inverters, and wind and solar generation, I figure the boat could power a small third-world country. Just need a long extension cord.
|Room for more.|