2 6-volt or 2 12-volt batteries

I look at 6 volt batteries as half a 12 volt battery in a more convenient package. I can lift a 6 volt 235 ah battery with one hand if it has a handle, lifting an 8D battery (12 volt deep cycle 235 ah) takes deep knee bends and a 5 minute warm up before or a chiropractor visit after... :)

All I say is start from what you need, not what batteries you want, and work backwards. first is how many AH at what voltage, second is how to get to that point. I personally use four 6 volt batteries in a 465 ah 24 volt configuration tied to two 12 volt 250 ah (each) start batteries. The starts back up the house batteries, the house batteries can back up the starts, and the generator has a separate start battery so I should be really upset if I ever really run out of power....

Brian

Brian

One of the best reasons for two 12's is a bit of a test. Disconnect one, and see how long you last. Now you will know pretty accurately how long two will take you.

With two sixes you will know when you run out.

rbp111 wrote:
Granted, 2 6-volt golf cart batteries last longer than 2 12-volt batteries. But what if one of the 6-volt dies, are you with out all power until a new 6-volt battery is purchased?

Well, you have two bad assumptions in that one paragraph, I will cover.

2 6 volt last longer than 2 12 volt: Generallly that is true but while when we speak of six volt we are normally talking GC-2, 230 amp hour DEEP CYCLE (115 amp hours usable) (This is at the 20 hour rate).

When we talk about 12 volt there are dozens of different batteries, Many can be had in Deep Cycle if you are willing to look hard and pay through the nose. a pair of 8D 12 volt for example, will outlast that pair of 6 volt by a factor of over 2x, (Each 8D is about the same as the six volt pair all by itself, also as heavy as the six volt pair)


Second. There are no six volt batteries in an RV, only 12 volt, some of them come in two smaller halves for ease in handling and savings in price (Since the GC-2 is the single most produced lead acid rechargable the cost per unit is lower).

So though oney one of the six volt goes bad.. Actually usually only 1/3 of it goes bad.. But that is the same as if one cell in the 12 volt (1/6tgh of the 12 volt battery) went bad.. You replace 'em both.


Now to the 'Are you out of power' question: Depends. on shore power no, the converter will continue to convert.

If you are worried about, say the time it takes you to get to Sam's club from the campground.. No reason you can not put a small 12 volt (Say a Group 27) in parallel with the six volt pair. Some folks yammer about "The smaller/larger" battery chargin faster or slower and all sorts of dire warnings.. They should really research what they are saying.

(Fact, batteries in parallel, after the first charge/discharge cycle, are always in LOCK STEP when it comes to state of charge, if one of 'em is at 99, so is the other) Yes the larger battery will take a bigger share of the charge current (and provide a bigger share when powering the loads) but it's in perfect proportion to the size)

I am still wayne_tw wrote:
When using two 6 volt batteries wired in series, you double the volts but the amp hours remain the same.

When using two 12 volts wired in parallel, you double the amp hours but the volts remain the same.

Therefore, using two 12 volt batteries you will have greater capacity for the size of the battery bank than using two 6 volt batteries.

I agree with Wayne for the most part. The advantage to true 6v golf cart batteries is the plates are thicker and can take more abuse with heavy discharging. Other than that volts are volts and amp hrs are amp hrs. Just my 2c.

Another point, if you do a cost analysis, two 6v golf cart batteries aint a bad proposition and IMO are a good long term value.

My next two batteries will be 2 12 volt agm's. But lots of people love their 6 volt batteries. To each there own. I can see some logic to the idea if one battery dies you would still have a second twelve volt battery to use as long as you have a charging source. But that would be highly unlikely.

Go with whatever offers the greatest number of amp hours. In our case it was 6 Volt Trojan batteries. Good luck.

I went with two 6 volt for the slightly larger capacity and the reported longer lifespan. They are going still strong almost seven years later - longer than I ever got out of a 12 volt - so I'm happy with my choice.

When using two 6 volt batteries wired in series, you double the volts but the amp hours remain the same.

When using two 12 volts wired in parallel, you double the amp hours but the volts remain the same.

Therefore, using two 12 volt batteries you will have greater capacity for the size of the battery bank than using two 6 volt batteries.

bldrbuck wrote:
It really does'nt make much difference which you buy.

x2

rbp111 wrote:
But what if one of the 6-volt dies, are you with out all power until a new 6-volt battery is purchased?

Assuming you're not talking about death from abuse or old age, it's specious reasoning.

The same argument could be applied to any 12v battery. What if someone dry camps with one 12v battery? Do we advise him/her to carry a spare? 2-6v batteries in series are nothing more than a 12v battery in two pieces, and it's no more likely to catastrophically fail than a 12v battery.

Having one battery fail is possible, yes, but probable? Hardly.

12v vs 6v batteries 2013
12v vs 6v batteries 2006
More 12v vs 6 2006
12v vs 6v 2010
Why 2 6? 2006

Anybody had one 6v fail?2010

maybe 12v is better 2010

It really does'nt make much difference which you buy. The life will be the same either way. I go with two six volts just because the plates are heaver in them..