Educate me on 12 volt batteries

[Guy_Roan]

O

[dodge_guy]

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[profdant139]

oldwizard asked what other spare parts we carry. The answer is "several," but a spare battery is not just a spare battery in case the first one dies. Instead, it is a "swap out" battery -- we know for certain that our main battery will need charging after a few days (unless we have sunshine).

So then we swap the old one out and put the new one in. It's not a matter of "if." The issue is "when."

For each trip, I alternate which one will be my main battery and which one will be the spare.

By the way, my very risk-averse method of battery maintenance sacrifices the Peukert effect -- if I were to hook the two batteries together, I'd more than double my capacity.

But then I would have to recharge both batteries at the same time.

With my "spare battery" strategy, I can take the discharged battery and my portable solar panel into a sunny place and recharge, even though the trailer is parked in deep shade (which is what we usually do).

[2oldman]

theoldwizard1 wrote:

Curious. What other spare parts do you carry ?

Water pump.

[ktmrfs]

philh wrote:
6V or even lithium generally require a charger upgrade

lithium does require a different charging profile , but any flooded cell or AGM lead acid charger doesn't care if what configuration of 12V battery you have, they all have 6 cells in series. either 6 in once case or 3 each in two cases, or 6 individual 2V cells in series. It's all the same.

[philh]

6V or even lithium generally require a charger upgrade

[theoldwizard1]

profdant139 wrote:
I'm with parcany. I carry one 12v battery and a spare.

Curious. What other spare parts do you carry ?

[ktmrfs]

2oldman wrote:

opnspaces wrote:
I can recall only ONE report of a single 6 volt battery failing unexpectedly. It just doesn't happen.

Golf courses the world over can attest to that fact.

and also that you can discharge them well below 50% SOC and still get hundreds and hundreds of cycles out of them.

Personally I know of more people who have had a 12V battery fail on them while camping than 6V (0 on the 6v). Now granted many of the failed 12V were from campers who had no idea of what it takes to maintain a battery and had unintentionally really abused them.

[2oldman]

opnspaces wrote:
I can recall only ONE report of a single 6 volt battery failing unexpectedly. It just doesn't happen.

Golf courses the world over can attest to that fact.

[opnspaces]

Granted this forum represents just a small slice of the millions of RV's and RVers. But in the 16 years I've been reading and contributing here; I can recall only ONE report of a single 6 volt battery failing unexpectedly. It just doesn't happen.

[2oldman]

parcany wrote:
Yes if your one 12 volt battery goes bad nothing will work anyway.

Correct, so the argument about one 6v 'going bad' is sorta moot. The chances a 6v battery just up and 'goes bad' for no reason are remote at best. That would usually be because the user ran them down or they're way too old and tired. The best way to rescue yourself from any battery failure is to carry a spare.

[valhalla360]

Guy Roan wrote:
Off and on I see posts regarding changing out the 12 volt battery to two 6 volt ones.
In the past thirty years I have had three trailers and never had a problem with the single 12 volt battery so could someone please explain the reason for swapping to two 6 volt ones.

Guy

If you stay at parks with shore power, even a cheap automotive battery will do just fine. It would actually be silly to upgrade as you will never use the advantages.

If you are going to be camping away from shore power (and generator), an upgraded battery bank means you don't have to be paranoid about running out of power.

[Grit_dog]

Guy Roan wrote:
Off and on I see posts regarding changing out the 12 volt battery to two 6 volt ones.
In the past thirty years I have had three trailers and never had a problem with the single 12 volt battery so could someone please explain the reason for swapping to two 6 volt ones.

Guy

Never had problems?
Be more specific. Nothing wrong with a 12V battery. However a statement like that makes me think your camper is plugged in to AC power most all of the time.

[profdant139]

I'm with parcany. I carry one 12v battery and a spare. If the battery in use dies or gets too low, I swap 'em out. This is a "belt and suspenders" approach. With two 6v batteries, you've got more capacity, but only as long as both batteries are healthy!

But there is a catch to my method -- this limits me, of course, to the capacity of one 12v. Since these are group 31 batteries, that's a total of 110 amp hours per battery, which means I can only use half of that without overtaxing the battery.

This system works if you are an energy miser (like me) or you have solar (which I do) or recharge with a generator (which I almost never do) or recharge at an RV park (which I do from time to time, especially if we have to do laundry).

[time2roll]

parcany wrote:
Maybe I am wrong but I agree 2- 6 volt have more amp hours but if one of the 6 volt batterys go bad than you only have 6 volts and nothing in the trailer will work. Yes if your one 12 volt battery goes bad nothing will work anyway.

Yes however a shorted cell in a GC2 seems to be far more rare than a 12v marine battery.
4x GC2 also reduces to possibility of being stranded.