6 volt versus 12 volt HELP

Hi Mena,

I'm saying that a 400 amp-hour single twelve volt battery would be better than 8 100 amp-hour six volt batteries.

pianotuna wrote:
Hi mena,

Nice find!

Cell count needs to be as low as possible for the capacity required. That, in my opinion, suggests that 8d AGM would be a better "fix" than an equivalent amp-hour number of six volt units.

You can get much higher capacity 6V AGMs with same amount of cells as a low capacity 12V. I'm not sure I follow what you're saying.

Hi mena,

Nice find!

Cell count needs to be as low as possible for the capacity required. That, in my opinion, suggests that 8d AGM would be a better "fix" than an equivalent amp-hour number of six volt units.

The acid is held in glass mats but there are still plates. And plate shedding still occurs. I found this.

Valve-Regulated Lead-Acid Batteries

The issue on 6V or 12V AGM batteries was a long time ago and died off without a final resoluion at the time. I didn't push the issue too much back then.

In the discussion, another RV'er I admired had a small well-equipped Winnebago Class C that he had retrofitted with two 6V AGM batteries and I wondered why he had chosen two 6V instead of two 12V.

I believe that AGM batteries use some kind of "mesh" to hold the chemicals in suspension or maybe some kind of "mesh" instead of plates? Probably "room at the bottom of the plates" or "plate thickness" considerations do not apply when comparing deep cycle 6V AGM to deep cycle 12V AGM ... although good old weight-of-the-lead still applies regardless of how the lead is configured in an AGM battery.

Ask the manufacturer for information. Plate thickness. All are 100% virgin lead so composition is not a factor.

Type and technique of glass mat separators. Electrolyte in both 1.300 ?

If they waddle and quack you got you a duck, black or white.

Hi,

I'd be interested too, Phil.

pnichols wrote:

I once raised a question in a forum discussion that was never answered: If you were going to spend the money for AGM, what about 6V deep cycle AGM batteries - would there be any advantage in them over 12V deep cycle AGM batteries?

Hey PN, can you repost that in a new thread? Maybe we can get some discussion on that. I have an opinion on that but don't want to get off track here.

pnichols wrote:
Bear in mind that RV batteries should always be of the "deep cycle" type and that's what 6V golf cart type batteries are. To get 12V deep cycle type batteries that are of the exclusively deep cycle design, there's not much choice other than AGM ... which is expensive.
...

Ahhh, I missed the fact that your 29's are AGM. And yes, what I've been reading about AGM has been very positive, except the cost (~3x more per Ah), and the fact that you can't measure sp.gr. (which may be a blessing ... one thing less to fuss over). They also tend to be a lot heavier, but that's not as important to me as I could move them inside off the tongue and back closer to the trailer axles.


That still leaves PianoTuna's 29s. Are not they the "Marine" variety? Maybe he got lucky and picked up a couple of good batches, or maybe his charging regime is optimum, or what's finicky to some is easy to others, ...


Just realized that another consideration in choosing batteries is the ability to switch banks so that you can equalize one bank at high voltages (as much as 16V?) while safely using the other at more reasonable voltages. Guess this is important only when boondocking for long periods; not sure if it's important to us. But if you're doing daily equalization or finishing much over 15V then it's probably necessary. It does mean that you need at least 4 6V batteries, but only 2 or more 12V.

Bear in mind that RV batteries should always be of the "deep cycle" type and that's what 6V golf cart type batteries are. To get 12V deep cycle type batteries that are of the exclusively deep cycle design, there's not much choice other than AGM ... which is expensive.

So to easily find deep cycle batteries that are affordable, there's not much choice other than common 6V wet cell golf cart batteries.

I once raised a question in a forum discussion that was never answered: If you were going to spend the money for AGM, what about 6V deep cycle AGM batteries - would there be any advantage in them over 12V deep cycle AGM batteries?