I am going to give you the same advice that Maine
Sail gave me when I was thinking about a dedicated started battery. I think you are overthinking the need for a dedicated started battery and that a large primary bank with a smaller reserve bank would be a more versatile setup. You could set this up with a simple 1/2/Both/Off switch.
I don't know anything about the VSR relay you linked to. I used a Blue Sea Systems ACR. I am really happy with the performance of this product.
To figure out the size of the bank you would need to power consumption
workup. Then you can think about how long you would want to be able to go assuming cloudy weather
and no wind (i.e. no power generation). On the wind power, many of the cruisers I have talked to ended up ditching the them. Good concept
but they are noisey and don't make as much power as they are an inconvenience. Based on all of the reviews
I have gotten either from the internet
or cruisers, I am going with solar
Here are some links to help you figure out what you want to do.
1) 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. 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) I added a positive distribution buss, wired my alternator directly to this buss, added an ACR and a battery monitor
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). 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. 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
while you are at it. I have both. And when you purchase
, go with Poland
Springs. As usual, Maine Sail has done the legwork
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.
is something I am still working on
but will add this year. A good place to start is this article
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,