Books on boat battery systems

[dmksails]

I was recently on a boat that used 6VDC batteries as the house bank and I was impressed with the capacity - we went 36 hours with the batteries supplying amps to the lights and refrigeration and stereo and never came close to draining the bank.

I'm going to be moving my house bank to a new location on my boat and this would be a great time to make any improvements to the system. I currently have 2 12vdc 105A batteries in the house bank.

I'm looking for suggestions for a book(s) that would describe setup and requirements for using 6bdc batteries to supply a 12vdc system. I have the Calder book on Boatowners Mechanical and Electrical Manual which has a few paragraphs on the subject. Looking for something with a little more depth.

Not looking for pros/cons - there are already alot of good posts here on that topic.

[SailingHarmonie]

There is nothing magic about 6 volt batteries. You get the same power density measured by weight or volume as you get with 12 V batteries. You could use two 210 A-hr 6 volt batteries in series instead of two 105A-hour 12V batteries. You'll have exactly the same capacity, they will weigh the same and take the same cubic space.

Assuming you are buying GOOD quality 12V batteries, using 6V batteries there are some small gains in efficiency, and potentially in life span, but nothing you would notice in day to day service. In a case like yours with a rather small battery bank, there is nothing at all complex about it. You just connect the positive terminal of one battery to the negative terminal of the other, with a cable sufficient to carry the heaviest current draw, and then treat it like one big 12V battery. Realistically, the only advantage of splitting the bank into two 6V batteries is that each one is half the weight of a single 210A-hour 12V battery and is therefore easier to install.

Unless you are greatly expanding the overall capacity of your bank, your best case is just two 6V batteries of the largest size you can. You will either run out of money or space first...

[Bowdrie]

Part of the equation is available real estate, both in the horizontal and vertical.
With 6V batts, if you have lots of height you can increase capacity by just getting taller batteries while keeping the same footprint.
If a "T-105" isn't enough another ~2in. of height gets you to a J-305, want more, then another ~2in. brings you to an L-16.
Then the problem becomes weight, lifting an L-16 is a job for Charles Atlas, or Conan.