Eric,
I am going to give you some replies with a bunch of links from my experience.
1) Forget about the 4D batteries. They are not good deep cycle batteries and are actually a multi-purpose. Look into 6 volt golf cart batteries or Group 31 12 volt. Thankfully,
Maine Sail has already done a lot of the homework and identified a quality, affordable brand. The Duracell ECG2 from Sam's Club. I recommend looking into going with a large primary bank and a small reserve bank. See below for sizes.
2) While AGM or gel may be appealing, stick with the flooded. You need to do a lot more
work to go with AGM or gel that is likely not worth it for you.
3) Spend some time reading about the
1/2/both/off switch and how to properly setup your new system.
4) You might also want to consider a couple other upgrades while you are at it. For instance, I a
dded a positive distribution buss, wired my alternator directly to this buss, added an ACR and a battery monitor. Definitely worth taking the time to understand these system and consider/plan an upgrade.
5) Do a power consumption workup to help you size your batteries and solar panels appropriately. I have attached mine but this is based on being full-time liveaboards and cruisers. Your use will likely be different and change some of these aspects.
6) Once you do the power consumption workup you can size your bank(s). Again, I recommend going with a primary bank and a reserve bank. I helped a friend install two of the ECG2s as a primary bank with a group 27 as the reserve bank on his Catalina 30. This gave him a primary bank of 230 Ah and he was fine using his boat for weekend and vacation cruises with this setup. No need to go too big if you are not going to use it. Your boat has two 180 Ah banks but they are probably not getting that type of capacity any longer due to age. I went with
4 of the ECG2 for a primary bank of 460 Ah and a Group 24 reserve. It's a tight fit and I had to make some compromises to get them in. You want to
pay attention to orientation when you install the batteries.
7) When you go to buy the components, don't cheap out. I used some lower end components and have either replaced them or are planning to. Go with something like Blue Sea Systems or another well respected marine grade company. Saving a few bucks on a cheaper ANL fuse is not worth it. I did it and had an 80 amp ANL fuse go with no sign of blowing. It cost me a weather window to leave a fogged in port in Maine while I diagnosed the problem. Could have been a lot worse. I now only buy Blue Sea Systems fuses (but this might have to change, see the 800 lb gorilla post from MS).
8) Consider adding a battery watering system. I went with the
Flow-Rite system and love having it. At the very least consider a
battery filler. And get a battery
hydrometer or
refractometer while you are at it. I have both. And when you purchase distilled water, go with Poland Springs. As usual,
Maine Sail has done the legwork for you.
9) Go with good quality battery boxes and remove the fiberglass tray that the factory installed. On mine they screwed through the bottom and it wasn't watertight any more. The
Dyno boxes sold here are great. Also, pay attention to the hold down system in the orientation article above.
10) Solar is something
I am still working on but will add this year. A good place to start is
this article from Compass Marine Services (aka Maine Sail's business page). It is a great primary on how to size and on how to install.
11) As to the type of panels, that will depend on a lot. I am currently leaning towards Renogy bendable solar panels installed on the bimini and some other places. But this goes against all of Maine Sail's advice. It's a cost thing for me at the moment. But the reasons I have not made this purchase is because Maine Sail does have really compelling reasons why he recommends Solbians for this type of panel over the other brands that are available. It's a very tough choice. Quality vs. cruising kitty. I will definately go with the flexible panels. Just not sure on the brand yet.
Hope this was helpful.
Good luck and fair winds,
Jesse
