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Old 07-20-2018, 04:45 PM   #19
Captain Ron D
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City: San Diego, California
Country: USA
Vessel Name: Seas the Moment
Vessel Model: Mainship 400
Join Date: Dec 2016
Posts: 20
Quote:
Originally Posted by sdowney717 View Post
I just replaced all the boat batteries over the last 2 months.
All are 12vdc, I had wondered about using golf cart cg2 batteries, but nixed the idea. Costs a lot more, and if one goes out, then I dont have 12 vdc and nothing will work.

I now have a Commercial Farm group 31 CarQuest for starting both engines.
https://shop.advanceautoparts.com/p/...1p30/2100010-P

I now have two group 27 Duracell Deep Cycle from Sam's Club. At $82 each seems worth it.https://www.samsclub.com/sams/durace...-also-viewed:9

The gen has its own start battery. As long as the gen starts it is never a problem, can use as much electricity as anyone could want out there.

I have no need for a larger bank of batteries. No gen, then that's a different story for me.

One weekend, all was fine, go out to boat midweek and 2 batteries went out with shorted cells, they were from 2012, so 6 years old.

I noticed the problem when checking the volt gauges, one bank was trying to charge at 15.6 vdc. And some gassing could be heard, batteries were warm. And when I pulled them out, some acid had leaked.

With the new batteries back to 13.6vdc.
My old Raritan 3 bank charger tries to compensate with failing batteries by raising the charge volts on whatever bank is going out. I had also noticed last use of boat, the house bank had run down a lot sooner than usual, I dont always run the gen.

Not quite: You said " I had wondered about using golf cart cg2 batteries, but nixed the idea. Costs a lot more, and if one goes out, then I dont have 12 vdc and nothing will work." My system used 6 each 6 volt GC Batteries.
2 clusters of 3 each 6 volts in PARALLEL. This gives you 675 AH at 6 volts (225 AH each) NOW yuu take the two clusters and hook them in SERIES, + to - and you will have 12 volts across the OTHER + and - TERMINALS.


With me so far? Say one of the 6 volt batteries craps out. You simple pull that one from its bank of 3, and reduce the OTHER BANK by pulling one from that bank. Now you have 12 volts, but only 450 AH.



If one more craps out you pull one more from each bank (pull the bad one) and hook up the banks and you will have 12 volts but only 225 AH, still enough to crank over your engine.


Maybe I am missing something, but I ran my 38' Cheoy Lee Sportfisher for 15 years using that system as the HOUSE bank, albeit I could have also used it to start the diesels.


However, if you are happy with the Group 27 Deep Cycles Duracell's from

Sam's club, then go for it. Keep in mind, in my application I was on the hook often for for two weeks in Catalina Island Harbor off California, where you cannot run your genset until 0800 and Mama had to have her coffee at 0730 when she arose !! Remember, If Mama's not happy, NO BODY is happy. Captain Ron has spoken !!

Captain Ron D
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