6V bank to replace 12V bank

[hlev00]

Originally Posted by onestepcsy37

thomm225 - i think the comment was that, with two golf cart batts you have 6 'watering holes'; with two 12v batts you have 12 watering holes.

But you need four 6V (t105) for approx the same capacity as two 4D 12V. Ultimately it is the same number of cells.

[silversailor]

As it turned out, my battery location will not accommodate the taller 6V batteries, so I'm back to 12V. My current batteries are Varta, which arrived along with my boat from Germany in2006. Anyone know where Vartas are available in the US? Any suggestions for 12V Gp 31's. What about a Gp 27 "dual purpose" for the starter? Any experience with Exide Nautilus batteries?

[Kettlewell]

I've got some Interstate GP-31 12-volts on my boat that are in service since spring of 2007. I would still look at Sam's Club batteries--not sure what they have in that size, but they tend to have good batteries at good prices. MaineSail has gotten more than 6 years out of some WalMart batteries. I've used a WalMart "marine" battery for my starting battery for several years, and I believe it is Exide. No issues whatsoever, and I like the fact that if I did, WM tends to swap batteries without any hassles.

[onestepcsy37]

the 'standard' golf cart battery - like a trojan t-105 - measures 10 3/8" long, 7 1/8" wide, 10 7/8" wide, and weighs 62 lbs.

kettlewell, i was at my local sams club the other day and they didn't have size 31 batteries - biggest was size 29, price $95 for the 'deep cycle'. golf cart batteries were $85.

seems like all the sam's club batteries are now made by 'east penn'.

[Kettlewell]

I'm pretty sure there is no "real" GP-29 size--it was created for WalMart, and in reality GP-29 and GP-31 are the same size and capacity.

[settingsun]

Years ago we upgraded our trailer from two 12-volt Group 24's that came with the trailer to two 6-volt Costco batteries.

It was a great upgrade -- we went from 140 amp-hour capacity to 220 by making the switch.

[Kettlewell]

A couple of good GP 31 batteries will have around 220 AH too, but theoretically the golf cart 6 volts will last longer due to the thicker plates which can withstand deep cycling better. One issue I see with having only two 6-volt batteries is that if one dies for some reason, you are than left with only 6 volts. Of course, if you have at least 2 6-volts surviving you should be able to rewire to get to the needed 12 volts.

[settingsun]

Kettlewell, you have a great point about possibly losing one battery.

In our experience, however, we've been living exclusively on solar power for six years now, alternating between a trailer and a sailboat, and we've never had a battery fail. As long as you maintain them, I think they're built pretty well and will last... our Trojans on our current trailer have been in service for 5 years.

[Kettlewell]

In our experience, however, we've been living exclusively on solar power for six years now, alternating between a trailer and a sailboat, and we've never had a battery fail. As long as you maintain them, I think they're built pretty well and will last... our Trojans on our current trailer have been in service for 5 years.

I agree they are reliable, but it is always good to have backup plans. I have had batteries fail prematurely--one time half way between Providencia and Honduras offshore, but I was able to rewire the bank as they were all 12-volt batteries. It was an internal short apparently, on a less than 2-year old battery. Got very hot on a long motoring run, but luckily I smelled it before there was a fire.

However, I think you are right that the Trojan 6-volts are among the most rugged and long-lasting batteries out there. I did once live for 12 years onboard a cat that had Sonnenschein gel batteries, 12 volts, and I retired them after 10 years because I was getting worried, but they were still going strong at that point.

[foggysail]

Originally Posted by Kettlewell

I'm pretty sure there is no "real" GP-29 size--it was created for WalMart, and in reality GP-29 and GP-31 are the same size and capacity.

Interesting!!!

[gpeacock]

So if you have 4 6V bats. What is the best way to wire them up for 12 V power?
Nigel Calder advocates Series Parallel with Jumpers. (as Andina suggested)
Trojan advocates Series Parallel with out jumpers as shown here: http://www.trojanbattery.com/tech-support/techologylibrary/connectionsdiagram.aspx
What about Parallel series as shown here: http://www.batterystuff.com/kb/articles/battery-articles/battery-bank-tutorial.html

They all have the same net result (12 V at 440AH) but my limited knowledge suggests that parallel series (option 3) forces the electrical path through all the batteries (It seems it can skip at least one battery on the other options).
Thinking about cables to connect things... Option 1 requires six cables, option 3 requires five cables and option 2 requires four.
Hmmmm. 6V bats have been around for a long time. Surely someone has done research on this and can definitively say which way to connect is best.

[savoir]

There was a great thread about this a few months ago with diagrams. Anyone remember which one ?

[AnchorageGuy]

Originally Posted by gpeacock

So if you have 4 6V bats. What is the best way to wire them up for 12 V power?
Nigel Calder advocates Series Parallel with Jumpers. (as Andina suggested)
Trojan advocates Series Parallel with out jumpers as shown here: http://www.trojanbattery.com/tech-support/techologylibrary/connectionsdiagram.aspx
What about Parallel series as shown here: http://www.batterystuff.com/kb/articles/battery-articles/battery-bank-tutorial.html

They all have the same net result (12 V at 440AH) but my limited knowledge suggests that parallel series (option 3) forces the electrical path through all the batteries (It seems it can skip at least one battery on the other options).
Thinking about cables to connect things... Option 1 requires six cables, option 3 requires five cables and option 2 requires four.
Hmmmm. 6V bats have been around for a long time. Surely someone has done research on this and can definitively say which way to connect is best.

Here is how I try and always wire multiple batteries in a bank using golf cart batteries, The Trawler Beach House: Relocating The House Batteries . The alternator, battery charger, load out to panels, etc. are all connected to the power post and not to any battery posts. Chuck

[nigel1]

Originally Posted by savoir

There was a great thread about this a few months ago with diagrams. Anyone remember which one ?

was it this one??

http://www.cruisersforum.com/forums/...ank-77717.html

[onestepcsy37]

here's the trojan battery users guide, in pdf format. go to page 9 for the diagram of how to wire 4 golf cart batteries correctly. there's a whole lot of other good advice in here.

http://www.trojanbattery.com/pdf/TRJ...UsersGuide.pdf