6v vs 12v batteries

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Gorse

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Feb 14, 2008
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I have already gotten some useful info on this subject by scanning previous posts, but I was looking for a little more input.
I currently have 4 6v batteries, 2 sets of 2 which are linked in series and then the sets are connected in parallel. With this setup I am calculating that I have approx 440 ah at 12v. Right now I have one battery with a bad cell, and replacement batteries are priced around $140. I can get 12v deep cycle marine batteries for around $75, so I could almost by 2 for the price of one 6v. I would then have 2  6v in series connected to 2 additional 12v in parallel, and it should give me something close to my original capacity.
Anyone have any comments on whether this is a good idea or should I just spend the money on the 6v and keep the existing setup?

Thanks
 
The two six volt pairs should give 264 amp hours (232 per pair) or 232 usable amp hours (50%)

There are some folks who go on and on about slightly different chemistry in the Golf Cart batts.  I suspect they are right, but frankly, I have not the means of testing.  I know the construction of the golf cart batts is a bit more "robust" from the viewpoint of you can neglect them somewhat more than a 12 volt for the most part,  They can take more "use abuse" (As opposed to physical abuse)

(Physical abuse is bouncing, banging and slamming like on a 4-wheel off-road run-about, Use Abuse is deep discharge, not checking fluid levels, that kind of thing)

Thus I'm inclined to support the pair of golf cart batteries option.

However from a pure tech. standpoint, which is how I'm trained to think

232 amp hours is 232 amp hours and it don't matter how you get there
 
The two six volt pairs should give 264 amp hours (232 per pair) or 232 usable amp hours (50%)
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Looks like a typo there John. You probably meant:

The two six volt pairs should give 464 amp hours..... (I use 440AH as a generic number).
 
I can get 12v deep cycle marine batteries for around $75, so I could almost by 2 for the price of one 6v.
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The "marine" batteries are likely to be combination deep cycle and starting batteries, which are a compromise for both purposes. Go with the golf cart size 6V batteries for repeated deep cycle use.
 
I have had 4 6v golof cart batteries in our last two coachs and have had FAR better luck with them than we ever had with previous 12v dual purpose marine batteries. The current set are four years old and as full timers have been well used. They are in as ggod a shape asthey were new.

Incidentally I just saw Interstate 6v batteries for 99.00/ea so you might do a little more shopping. (I would recommend Interstate or Trojans). 
 
Gorse said:
I can get 12v deep cycle marine batteries for around $75, so I could almost by 2 for the price of one 6v.
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No you could not.  Tom is right.  Those marine batteries are dual purpose starting/house batteries.  To meet the starting requirement they have more and thinner plates than the true deep cycle units that should be used for house batteries.  The marine batteries cannot take the frequent deep discharges that house batteries are built for.  

There no misery in RVing quite like running out of battery at 3am on a cold rainy night when you are boondocking without campground power.  :(

 
Tom said:
Looks like a typo there John. You probably meant:

The two six volt pairs should give 464 amp hours..... (I use 440AH as a generic number).
Click to expand...

OPPS.  Sorry about that, and yes, you are right,  Thanks for the catch and the correction


To the OP.  Though you can buy a pair of 12 volt batteries for about the same price.. Odds are they are on the order of 83-100 AH each, so you end up with LESS capacity

In terms of Bang for your Buck,, (Amp hours per dollar) it's hard to bead golf cart batteries

In fact With Golf Cart batteries we speak of Amp Hours per dollar (You can currently get about 2 AH per dollar, 3 if you get a sale, avoid Sams, batteries are CHEEPER not cheaper, Costco is good batteries)

But with some battery classes (Optima for example) I'ts more like Dollars per Amp Hour.
 
Thanks for the catch and the correction
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We knew what you meant John  ;D

In fact With Golf Cart batteries we speak of Amp Hours per dollar
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I learn something new every day; I had no idea we spoke in those terms  :-[
 
6 volt DEEP CYCLE batteries is the only way to go.  If one or more batteries used in a bank of batteries goes bad I suggest you just bite the bullet and replace them all since it is likely the others will go bad soon anyway.  I strongly recommend against any battery made by Exide based on personal experience.  I did notice that Sam's Club in League City TX is now carrying Interstate Deep Cycle batteries for around $63.  However I recommend Trojan deep cycle batteries as first choice.
 
Tom said:
I learn something new every day; I had no idea we spoke in those terms  :-[
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Well, I've seen Qualiity 6 volt for around 60 bucks a pop, that's 120 bucks for 232 amp hours, or nearly 2 amps per dollar

I've seen 12 volt AGM at around 200 for 100 amp hours, that's 2 bucks per amp.

Simple reading of the price chart with some SERIOUS rounding there.
 
I don't know where you guys have seen quality 6v for $60. When I was pricing them last spring the Trojans were running around $110. I finally bought a pair of offbrand batts for $42 each with a 1 yr. warranty and 5 yr. prorated warranty. So far they have not been using water anywhere near what the Interstate batts I had before that used and are holding up fine.

Woody
 
Costco, US-Batteries, appear to be equivalent to Interstate

However at 110 per batt for Trojans you are still over 1 amp hour per dollar, And from what I can find Trojains are the best

With Some other batteries you are more like 2-3 dollars per amp hour (Think optima)
 
John In Detroit said:
Costco, US-Batteries, appear to be equivalent to Interstate
Click to expand...

Not if they are made by Exide IMHO.

However at 110 per batt for Trojans you are still over 1 amp hour per dollar, And from what I can find Trojains are the best
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Probably the best wet cell deep cycle.  That is my first choice.
 
Per you Sams is Exdice

From what I understand Costco is US-Battery

In browsing US-Battery and Interstate I find that the most common RV house battery is a pair of U-220

On the US battery site it is US-220

In fact US  battery has a replacement for just about every battery Interstate has and the difference in catalog numbers is always the same.. Just change the leading letter to "US"
 
John In Detroit said:
Per you Sams is Exdice
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That is why I mentioned that I seen Sam's in League City were now also carrying Interstate Deep Cycle Batteries.  They may still have the Exide batteries too.  I had not seen INterstate at Sam's before.  They also had Optima Batteries.
 
Thanks for all the responses.
I am going to stick with the 6v, but I am not having much luck finding them below $130. The local auto parts store has an off brand for $144, Interstate has them for $135, and the local Sams Club/Walmart doesn't even carry them. Guess I need to keep shopping.
Thanks again
 
I have heard of folks getting Trojans, and other brand deep cycle, batteries from places that sell Golf carts and at better prices.
 
Also check with Solar Energy stores. Not sure about your state, but here in Arizona anything "alternative energy" (read deep cycle batteries) is sales tax free.
 
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