# 12 Volt Vs 6 Volt



## Scott and Jamie (Aug 27, 2006)

Why would you switch to 6 volt batteries? I haven't priced 6 volt batteries so are they cheaper at the auto store?

The reason I ask is because my brother just bought a new 5ver (cougar) and the dealer talked him into "upgrading to 6 volt batteries" $80.00 more (then of course they sale the almost new batteries).

As a electrician I can only what I do know about the difference between 12 volt vs 6 volt.

Two 6volt 200ah batteries, wired in series to create 12 volts, only have a "total" capacity of 200ah not 400ah. Two 6 volt batteries 200 ah wired in paralell will give you 400 ah @ 6 volts, but won't work with your charger converter in your TT.

2 12volt batteries 100ah each = total of 200ah @12 volts

2 6volt batteries 200ah each = total of 200ah @ 12 volts

2 12volt batteries 150ah each = total of 300ah @ 12 volts

Just curius why dealers and RVers say to use 6 volt batteries.

Scott


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## MJRey (Jan 21, 2005)

Check out these sites they have lots of information on deep cycle batteries and charging. Basically the 6 volt batteries are usually designed to tolerate deeper discharges. This gives you more usable capacity than comparable 12 volt batteries of the same rating. There are other differences as well and hopefully these sites will help you out.

http://www.solar-electric.com/deep_cycle_b...battery_faq.htm

http://www.uuhome.de/william.darden/index.htm


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## bentpixel (Sep 2, 2006)

Hi Scott,
I feel your pain. 
Three weeks (and may googles) ago I was where your sitting. 
12volt ??? 6 volt ?!!!









MJRey has some great links.

I'm ordering a pair of Trojan 6volt golf cart batteries: 105, 125, or 145 depending on fit and weight. This should provide about 200-250ah burn to 50% capacity. I have sleep apea and my CPAP air pump eats about 24amps in 8 hours (max). So can sleep a week w/o a recharge









Snoring can kill a vacation for DW. Then She'll kill me.









Here is what clicked for me. If the battiery rating guide has a number in the box for CCA (Cold Cranking Amps) then the battiery is at best a hybrid and may not last as long as a true deep cycle battery.

If you don't plan on dry camping much then it may not make that much differance in your situtation.

Charge on,


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## s'more (Jun 8, 2005)

Hey Scott,









If you decide to go with the 6er's, I got mine at Costco. I believe they were only $53 each. But, the only Costco in the Portland area that stocked them, was the North Portland store, just east of PDX.


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## Ghosty (Jan 17, 2005)

It truly boils down to cycling ... the 6 volt batteries are designed to take almost a full discharge and then recharge with virtually no damge ...

a regular 12 volt battery -- even the so called deep cycle - are not designed to drop below 10 percent of their load before damge "can" occur...

The two links below should be mandatory reading --

Lighter side of Batteries Part 1

Part two


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## PDX_Doug (Nov 16, 2004)

Another point that was brought up in a recent discussion, and worth considering, is that with dual 12V batteries, if one fails you have the option of isolating the good battery and continuing on (albeit with much reduced capacity). If one 6V battery fails, you are up the proverbial creek!

I was all set to switch to 6V's myself until that little tidbit was brought to my attention. Now I'm back on the fence again!









Happy Trails,
Doug


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## MRH (Jul 31, 2006)

How do you make a CPAP machine run off of DC voltage? It sounds as though you are saying that you run only with battery power. If you are hooked up to shore power, what difference dose it make?











bentpixel said:


> Hi Scott,
> I feel your pain.
> Three weeks (and may googles) ago I was where your sitting.
> 12volt ??? 6 volt ?!!!
> ...


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## Scott and Jamie (Aug 27, 2006)

Ghosty said:


> It truly boils down to cycling ... the 6 volt batteries are designed to take almost a full discharge and then recharge with virtually no damge ...
> 
> a regular 12 volt battery -- even the so called deep cycle - are not designed to drop below 10 percent of their load before damge "can" occur...
> 
> ...


Thank you all for your replies. One question why would you run your batteries down to 10% ? We did alot of dry camping with our last trailer, with one 12 volt battery, and I just kept a eye on the battery gauge. When it got to 1/2 I would fire up the generator for a bit. While we are dry camping we run a 600watt inverter in the eavning so the kids can watch a few movies and use the interior and exterior lights freely. In the morning around 10 we would top off the batteries and usually be good until the next morning. One of my thoughts was what doug said, one 6 volt goes bad and you are on generator 24/7.

Scott


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## skippershe (May 22, 2006)

i think i'll stick with 12v


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## JimBo99 (Apr 25, 2006)

I prefer the dual 6v batteries because of the deep cycle. What's the worry over losing one 6v battery? They will last a long time, and if one fails it is time to replace them both. If one fails while your out camping, how far is it to go to buy another pair? And besides, you can always borrow a 12v off one those guys that carry two just in case!


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## kmcfetters (May 7, 2005)

Was going to switch to the 6 volts---but I finally got a charge out ofthe 12 volts that I though were dead---so I am stuck with 12 volts for now---but if they die I am do the Ghosty thing----head to Sams club!


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## Husker92 (Feb 11, 2006)

I have two 12 V's and they work fine for me. Since I pull my batteries I put them on a Marine deep cycle charger before we go. We went 4 days with out a problem. However I did watch how many lights we had on at one time.


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## Scott and Jamie (Aug 27, 2006)

JimBo99 said:


> I prefer the dual 6v batteries because of the deep cycle. What's the worry over losing one 6v battery? They will last a long time, and if one fails it is time to replace them both. If one fails while your out camping, how far is it to go to buy another pair? And besides, you can always borrow a 12v off one those guys that carry two just in case!


Unfortunatley the closes 12v when I am dry camping is my brother in laws truck or mine. It would be about a 3-4 hour round trip from or camping spot to replace one. I have 2 on my outback and plan to add a third. I researched this on the web for quite sometime before origonally posting and found a majority of articles to say that there is no benifit going to 6 volt batteries. Most of the sites that supported 6 volt batteries was someones personal site. I think the biggest problem with 12v batteries is the TT manufactures go with the cheapest bidder. most 6 volt batteries weigh more than your local hardware /tire store cheap 12v, that is because they have larger internal lead plates. The larger the lead plates the longer the life of the battery. You can purchase a higher quality 12v battery and can get the same life out of it as a 6 volt. You can also buy a high grade 12v and out live the 6 volts.

Scott


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## Scrib (Jun 28, 2005)

Scott and Jamie said:


> You can purchase a higher quality 12v battery and can get the same life out of it as a 6 volt. You can also buy a high grade 12v and out live the 6 volts.
> Scott


Not exactly true, Scott - the proof is in the golf cart industry. If they could save a nickle by using 12V's instead of 6V's, they would. Truth is, they save much more than a nickle by using 6V's - Very few batteries can take a deep discharge-recharge cycle every day, and the 6-volt golf cart battery is the least expensive and easiest to find locally that can. Another point of research is the solar industry, where the battery-of-choice is the L-16, which is pretty much just a taller version of the 6V golf cart battery. Home solar systems are $60,000+, so if there was a better battery than the L-16, any additional cost would be relatively miniscule compared to the overall price of the system. And yet they predominately use plain old wet-cell L-16's.


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## Scott and Jamie (Aug 27, 2006)

Scrib said:


> You can purchase a higher quality 12v battery and can get the same life out of it as a 6 volt. You can also buy a high grade 12v and out live the 6 volts.
> Scott


Not exactly true, Scott - the proof is in the golf cart industry. If they could save a nickle by using 12V's instead of 6V's, they would. Truth is, they save much more than a nickle by using 6V's - Very few batteries can take a deep discharge-recharge cycle every day, and the 6-volt golf cart battery is the least expensive and easiest to find locally that can. Another point of research is the solar industry, where the battery-of-choice is the L-16, which is pretty much just a taller version of the 6V golf cart battery. Home solar systems are $60,000+, so if there was a better battery than the L-16, any additional cost would be relatively miniscule compared to the overall price of the system. And yet they predominately use plain old wet-cell L-16's.
[/quote]

Yes Iknow that the 6 volt golf cart is a better grade than your average joe 12 volt. But can you awnser why almost all "critical power" UPS systems use 12 volt deep cycle batteries? Have installed many and the 3 largest had 40 12 volt batteries. The 6 volt might work for the golf cart industry but why don't they use them for critical power systems? Why does every critical power generator I have wired or seen use 12 volt batteries instead of two 6 volts too start it? Sorry but I still beleive there is alot of myth around 6 volt batteries.

Scott


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## Moosegut (Sep 24, 2005)

I always had 12 volt bats on my sailboats and they never failed me on many overnights. It was just familiarity and success with the 12 volts that made me stick with them on the TT. I dry camp through the winter and a few years ago we were out in my old TT that had space for only one battery. It failed late Friday night and we had no furnace the rest of the night. On Saturday morning it was very easy to find a replacement down the road. I don't know that finding a 6 volt in an emergency would be as easy.

So, now I have two 12 volts with a Perko switch inside the TT. When I make a midnight run to the bathroom, I check the bat gauge and if the one is getting low due to the furnace, I just switch to the other. I also have a third bat that I hook up to a 400 watt inverter. I use that to run the TV and DVD player. I run the generator for an hour or two during the day and I'm good to go through the night again with absolutely no worries. It's personal preference but I'll stick with the 12 volt.

Scott


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## CamperAndy (Aug 26, 2004)

Does anyone remember that when cars first started to have electrical systems on board that they were 6 vdc? How about some of the new hybrids having 48 (and higher) volt systems. I also work on 125 vdc UPS systems that have a couple of hundred 2 vdc wet cells (set up in 3 banks of 60 batteries each).

Every application has many possible configurations and a pair of 6 vdc batteries to make one large 12 vdc bank is more or less equal to a a pair of equal weight 12 volt batteries. You could actually get one 12 vdc battery that is just as good as a pair of Trojan T-105's but you would not be able to pick it up.

The amount of lead that is used and the plate area that is exposed all have a part in this.

Personally I like the option of using a pair of 12 vdc batteries for ease of replacement but since MOST people that get a pair of 6 vdc batteries tend to monitor them closely. There is minimal chance that they will fail without warning and thus will be replaced before they head out for that 7 day dry camping trip 5 hours from anywhere.

Heck there are even 12 vdc batteries that use gel and not electrolyte in them and thus theoretically do not ever run dry. Can't wait for the AMG crowd to pipe in.


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## Scott and Jamie (Aug 27, 2006)

I have been looking into 4d and 8d 12 volt batteries for possible replacements. From what I can see alot of newer solar houses are starting to use these.


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## Scrib (Jun 28, 2005)

Scott and Jamie said:


> But can you awnser why almost all "critical power" UPS systems use 12 volt deep cycle batteries?


I'm only guessing, but I assume it's a size vs. Amps issue. I would guess that alot of "non-IT" SPS systems, i.e. for a building, use L-16's. I don't think the SPS/UPS application, where batteries are rarely cycled, is as directly applicable to RV'ing as golf carts that have their batteries cycled nearly every day.


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