6-v Batteries

[Dan de La Mesa]

Mostly because of ongoing comments on this forum about the superior performance of 6-v batteries over 12-v in dry camping situations, I had a guy come out last week and  replace my aging house 12-volters with two 6-v. I would have done it myself, but there was a lot of corrosion to deal with, and the former owner had installed a solar panel hookup that I wasn't sure I understood.

So the installer sweated out cutting through the battery holddowns, the bolts and nuts of which were rusted past loosening. He noted along the way that the previous owner had wired the batteries wrong, so that basically only one of the two 12-v was functioning. This is our third RV, and easily the poorest in house battery performance. Now we know why.

We're going dry camping tomorrow and hope to see considerable improvement. Already, the voltage indicator from the solar panel indicates over 14v charging during the day. We'll see how well the system holds at night with the light usage we give it.

By the way, the installer said that about 80% of the RV's he works on don't use traditional battery holddowns; that most owners wedge pieces of wood around the batteries in order to avoid the issue of future corrosion. That's what I did. I also checked the water level in the new batteries and felt that the level was lower than I was comfortable with. It's not now.

[SargeW]

It sounds like you are off to a good start. The choice of two 6 volt batteries was a good one. And yes, it's amazing how badly someone that doesn't know what they are doing can screw up a battery connection!  Let us know how the camping trip goes.

[MotorhomeLevel]

I don't really understand why 6v should be better than 12v? (btw: I have a veteran motorbike with 6v battery and all my friends try to change to 12v).
If you don't change the wiring as well the resistance of all your wires will considerably go up causing more losses. And do you have to change your equipment as well?

[John From Detroit]

Two comments
First water level... Battery instruction sheets often say to fill to the bottom of the "Split Ring" or the bottom of the filler tube (Same thing) Proper level however is 1/8 to 1/4 inch below that when filling.. Leave just a bit of "Wiggle room".. Refill with DISTILLED WATER when it's down near the top of the plates (But still over them) or when you feel it is needed whichever comes first.

Comment 2: Why are 6V better than 12 V

They are not.. at least not on paper... BUT what is different is this.
Six Volt are normally GC-2 Golf Car Batteries.. These are 220 give or take a bit Amp Hour, DEEP CYCLE batteries. they are NOT starting batteries.. Being DEEP CELL they are designed to deliver a relative slow discharge over a relative long time, and they have no problem with a state of charge as low as 50%.. Now.. Some may notice that in an emergency they WILL jump start your chassis.. This is true
But my chassis battery is 73 amp hours. so a 100 amp load is MORE than the C/20 rating, (A large load) for them, but less than half the C/20 rating of the GC-2's (A relatively small load)

Also, in the case of an Oh Cr**! level of discharge (Say 10 volts or less) fairly good chance of recovery if you don't do it too often.

Most 12 volt batteries sold for RV use are MARINE/deep cycle..  These are starting batteries with lip service to deep cycle,, they need to be kept fuller lile 60-70% minimum  50% SOC is an OH CR**! level on these batteries.. Still better than pure starting (add anothe 10%)  and the chance of recovery from a real deep discharge is .. Well Slight. 

Starting batteries the chance of recovery approaches ZERO.

Now why Six instead of say a 12 volt battery size 4D  (Basically the same 220 amp hours but now at 12 volt)... Pick one up and one answer will pop out of your back.. Then go see your chiropractor.   Six volts are 1/2 the voltage, 1/2 the WATTAGE (Same amp hour) and just slightly over 1/2 the POUNDS or if you like KGs.  Which makes them 4 times easier to wrangle.

They are also the single most popular lead acid battery on earth, Golf cars from sea to sea and beyond in all directions use them.. This means the cost of re-tooling to make a different size is basically zero cause they never retool. and that means they cost less per unit.

[Great Horned Owl]

I don't really understand why 6v should be better than 12v? (btw: I have a veteran motorbike with 6v battery and all my friends try to change to 12v).
If you don't change the wiring as well the resistance of all your wires will considerably go up causing more losses. And do you have to change your equipment as well?

You should understand that pairs of 6 volt batteries are wired in series, so the have 12 volt output from the pair.

6 volt batteries are not inherently better than 12 volt batteries. However, true deep cycle batteries are much better than the hybrid, marine batteries that are often used in RVs. 6 volt, true deep cycle batteries are used in golf carts, are fairly common, and are reasonably prices. 12 volt, true deep cycle batteries exist, but they are not comon, and tend to be very expensive.

Joel

[denmarc]

I don't really understand why 6v should be better than 12v? (btw: I have a veteran motorbike with 6v battery and all my friends try to change to 12v).

Maybe this article from the library will help you understand a bit better...

http://www.rvforum.net/miscfiles/Choosing_right_battery.pdf

[MotorhomeLevel]

Thanks for all of your explanations. I think I understand a little bit better 

[JFN]

When watering your batteries be sure they are fully charged as the water levels will be lower on a partially discharged battery.

[gravesdiesel]

You can get a 12 volt Trojan 1275 golf cart battery that is designed for the Club Car electric golf carts.  I run them in series in 24 volt floor scrubbers.  Would be a heck of a good RV battery.