House Bank: 12vdc x 4 or 6vdc x 4

[Sailmonkey]

Here's the question. I will be replacing/rebuilding the house bank, It will be four batteries. Do I better serve myself with 4 220AH golf cart batts for a total of 440ah, or 4 130ah group 31 12v batteries for a total ah of 520?
Other than the obvious abilty to remove any one or multiples of the 12v batteries and still maintain voltage, is there any lack of longevity when comparing the 12v batts to the 6v batts?

[Healer52]

I think it's mainly an issue of cost, size and space, weight to handle for replacement, etc.

[Sailmonkey]

Originally Posted by Healer52

I think it's mainly an issue of cost, size and space, weight to handle for replacement, etc.

I was always under the impression that the golf cart batts handle abuse better...........
where in Montana? I grew up south of Missoula.

[Healer52]

Originally Posted by Sailmonkey

I was always under the impression that the golf cart batts handle abuse better...........
where in Montana? I grew up south of Missoula.

It depends on the way the battery is manufactured: You can get deep cycle 12 v batteries too.

Kalispell....but right now I'm teaching in Ottawa, Canada.

[btrayfors]

I'd go with 6V golf cart batteries, because:

1. they generally have thicker plates, thus better to handle abuse and likely to have greater longevity; and

2. fewer inter-battery connections (golf carts would require 4; 12V batteries would require 6).

Bill

[Sailmonkey]

Does anyone know of independent test done on something like this? Lets say #of cycles (charge/discharge). In my mind I believe the Golf Cart batts would be better due to the thick plates but am hung up on the ease of single battery removal for a bad battery with the group 31's.

[witzgall]

One alternative to look into is the Trojan 1275. It is a group 31, 12v battery, rated at 150ah for the 20 hour rate. We have two as our house bank, and so far they have worked fine. We went with them as they were the most AH in a two battery configuration that I could find, with a reasonable cost.

Chris

[btrayfors]

Originally Posted by Sailmonkey

Does anyone know of independent test done on something like this? Lets say #of cycles (charge/discharge). In my mind I believe the Golf Cart batts would be better due to the thick plates but am hung up on the ease of single battery removal for a bad battery with the group 31's.

Don't get hung up on that. A single bad battery is a single bad battery. You can remove/replace a 6V battery just as easily as a 12V battery.

I think you're right: the golf carts will be a better way to go.

By the way, this fear of bad cells and single bad batteries is overblown in my experience. Get good batteries...all at the same time....treat 'em right, and you're unlikely to experience a bad cell or bad battery before it's time to replace the lot of them. How do I know? Lots and lots of battery tests, nine batteries to maintain on my own boat, six golf-carts to maintain at my home QTH, lots of client boats to work on. Yeah, it happens, but not all that often.

IMO,

Bill

[Troubadour52993]

I still have the 4 golf cart batteries that were on the boat when I got it 2 years ago. I did have to rewire the battery compartment, so I set them up in two banks with a selector switch, typically set to both, so I can at least isolate one pair if one battery goes bad prematurely.

You mention "single battery removal", which got me thinking. If one golf cart battery did go bad prematurely, would I have to replace the pair, sort of like tires? I was planning on a 5+ year normal life assuming charging twice a day with 50% or less discharge.

[btrayfors]

Originally Posted by Troubadour52993

......You mention "single battery removal", which got me thinking. If one golf cart battery did go bad prematurely, would I have to replace the pair, sort of like tires? I was planning on a 5+ year normal life assuming charging twice a day with 50% or less discharge.

No, just replace the bad one. It's best, of course, to have batteries all the same type and age, but you needn't be paranoid about it.

Your assumptions are good, if a bit on the optimistic side, IMHO.

Bill