12 volts to 6 volts; whats the benefit?

[Roman_Duck]

So we're replacing our coach batteries which are four 12 volts group 27 batteries.
We've heard some say they can get a longer run time off of four golf cart batteries over same number of deep cell types.
We were only getting a few hrs. of power before the existing ones would die. The reason for replacement. Two are about 5 yrs old the other 2 are about two years old. Guess we're lucky they work at all.
Was wondering if anyone else switched over and what was the positives and negatives? (no pun intended)
Appreciate any insights on the switch over (12 v to 6 v).
Also battery type will be a wet cell no AGMs, and any AH ratings versus cost would be helpful

[time2roll]

Custom cables to 4/0 right here:
http://www.genuinedealz.com/custom-cables/custom-battery-cable-assembly

Since you have the head room... if you want monster capacity consider some L16 for 840 amp hours. Going to be a bit more of an investment :B

http://usbattery.com/products/6-volt-batteries/us-l16hc-xc2/

[wa8yxm]

The Math:
12 Volt Group 27 MARINE/deep cycle times 4 = 380 Amp Hours and perhaps 114 usable before damage sets in big time

4 SIX volt in series/parallel forming two BIG 12 volt batteries = 420 to 460 amp hours of which you can safely use 50% (210 to 230) that is twice the run time

And very likely it will cost you less as well. since six volt gives the best Bang for Buck.

They are taller though.

[pianotuna]

How do you plan to charge the bank. How much off the grid camping do you do? Is any of it below -20 c (-4 f)?

[azrving]

Have you checked the specific gravity of your batteries? You could have problems with your next batteries if you aren't bringing the sg up on a regular basis.

[Roman_Duck]

Thank you to all, It sounds if the GC2 type is the way to go. There is enough space for the four of them, if I installed a shelf above the four I could install a second four(not happening), I know that it's best if all batteries are new at the same time, one of the reasons that we were switching over to 6 volts, is to be able to start with all new batteries. Cost seems to be equal to either type for the most part. The battery that smkettner referred to Sams 232 isn't available in the northeast. Looks like a suitable substitute will be the Duracell's 230

Thanks for all of the input.
Now how about a wiring diagram for seeting up the four 6 volt ?

[Gjac]

It is hard to find a true 12 v deep cycle battery and when you do the price is much higher than the 2 6 v GC batteries. I bought the Sam's club batteries for $74 each 7 years ago and they are still going strong and I dry camp 95% of the time. In 7 days of dry camping they are down to 50% SOC then they get recharged. So to me cost per amp hr over time is what is important.

[valhalla360]

The main difference is 6v batteries are almost always designed for deep cycle use (usually golf carts). Some 12V batteries are designed for deep cycle use but even some "deep cycle" labeled batteries are a compromise with starting design consideration making them less than ideal for true deep cycle use.

Assuming both batteries are designed specifically for deep cycle, then there isn't much differe. Then it becomes about which battery allows you to fit more amp-hrs into the available space.

[pianotuna]

Don't eat so many beans.

Naio wrote:

pianotuna wrote:

If you want long life, consider added a solar system.

Can I get one with only small planets? I can't see gas giants fitting in my minivan.

Sincerely,

The Little Prince

[time2roll]

Best value IMO is Costco or Sam's Club.

Costco is rated 208 and I believe Sam's has a 208 or a Gold 232 for a few more $$.

Sam's 232 gets my vote 464 amp hours vs 400 in your group 27.

Just make sure it has 3 fill caps. You would not be the first to bring home an 8 volt golf car battery.

The real benefit is that GC2 is that they are specifically designed for deep cycling. (starting a generator is not an issue)

Also the GC2 stay better balanced because you just have 2 parallel vs 4 parallel with Group 27. Half as many cells to water at maintenance time.

[MrWizard]

Bill.Satellite wrote:
You would need room for 8 6V to equal your 4 12V but it's really all about amp/hours so you have to look at what you have and what you would have if you change.

Totally wrong..
Where did you get that idea
Two 6v batteries have less cells and just as much lead (sometimes more) as two 12v batteries
And they hold up better under discharge..recharge cycles
You replace four 54# 12v batteries with four 62# 6v batteries
And come out ahead
After they are wired up, you have two big 12v batteries in parallel instead of four smaller 12v batteries in parallel

[Canadian_Rainbi]

Bill.Satellite wrote:
You would need room for 8 6V to equal your 4 12V but it's really all about amp/hours so you have to look at what you have and what you would have if you change.

Your math is wrong. GCs would be more than adequate. GCs have more than twice the amphour capacity of 27s. They have the same footprint as group 24, (which are shorter than 27s) but GCs are taller than either.

Group 27s run about 90 to 100 Amp hours each. Four would be able to provide 360 to 400 AH.

The "standard" Golf Cart type run from 220 to 240 AH

4 in series-parallel would provide 440 to 480 AH. 8 GCs would give 880 or more AH at 12 volts.

[chuckftboy]

The biggest advantage for using 6 volt batteries is, they are readily available in a true deep cycle version so they last a very long time and arn't expensive. Mine are in the 7th year of use and are still in good condition.
12 volt batteries often are Marine/RV type deep cycle and do the same job but because the plates are thinner, they have a shorter life cycle in a deep cycle operation.

[Naio]

pianotuna wrote:

If you want long life, consider added a solar system.

Can I get one with only small planets? I can't see gas giants fitting in my minivan.

Sincerely,

The Little Prince

[pianotuna]

Hi,

Do an energy audit. Select a battery that will allow the bank to be at least double that number of amp-hours.

If you want long life, consider added a solar system.