I had considered the use of two Trojan 6V batteries hooked up in series for 12V. Yes, a great amount of amp hours there, but super heavy and very expensive to boot. I can get an Interstate Group SM27 for about $125 locally. Oddly enough I found a source where I can get the 6V Trojan T105 (225 AH) for the same price, but I have to drive an hour and a half to get them. the chandleries around here charge double that price to buy them.
Of course I would have to buy 2 of the 6V, but with a 12V I can buy one now and get another down the road. I really doubt I will need that much reserve power, and I'm not sure the taller batteries will fit in the space I want to put them in. I have the Seavolt group 27 (West Marine label) that came with my boat, but I don't think its any good. It charges up to 12.3 V and that's it, I thought it was supposed to go up to about 14V?
Anyway, plenty of time to think about it and many other things to do before I get to that part. The first thing I need to do is figure out the switches (if any) I will need near the compression post if I decide to put on a steaming/foredeck combo light on the mast, and if I'm still going to leave off the all-round anchor light. I need to get the thru deck fitting complete so I can close up that part of the deck for paint and non-skid.
I have a Fry's electronics store here which is a great place to get switches & breakers, but none of this stuff is 'Marine Grade'... but I doubt that is necessary.