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##### General Discussion / Re: 6 volt vs. 12 volt

« Last post by**IBTripping**on

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**Today**at 01:58:18 AM

It might be easier to look at how much power is stored in the battery. Power is Voltage x Current (in Amps or Amp-Hours) to give Watts or Watt-hours. Your home utility charges you by the Kilowatt-hour, or 1000 watt-hours.

What you're missing is a 6 volt battery of similar footprint to a 100 amp-hour 12 volt battery will have200amp-hours capacity at 6 volts, not 100 amp-hours. 6 volts x 200 amp=hours = 1200 watt-hours. Put two in series and you'll have 12 volts x 200 amp-hours, or 2400 watt-hours.

And only store half as much power as a pair of 6 volt batteries - 12 volts x 100 amp-hours = 1200 watt-hours. You'll need two connected in parallel to equal the capacity of a pair of 6 volt batteries of similar physical size.

I added "of similar physical size" because some people will cite an example of a 12 volt battery that gives the same amp-hour performance as a typical 6 volt battery. They exist, but they're twice the size and twice the weight as a similar amp-hour 6 volt battery.

I think I'm getting a better understanding of 6v vs. 12v. My TT is a 12 volt system. To use 6v I'd need at least a pair wired in series which equals 12 volts. But, according to Karl Kolbus in the library: "We mentioned earlier that some RVs might come equipped with two 6-volt batteries.

Unless it is a very, very old RV (think 1940’s), we can be pretty sure that they are wired in

series to produce twelve volts. The positive (+) terminal of the left battery is connected to

the negative (-) terminal of the one on the right. Again assuming each battery is capable of

outputting 100 ampere-hours, you might think that the total capacity would be 200Ah, but

that would not be correct. When batteries are wired in series, only the voltages of the

individual batteries are added together (6 + 6 = 12 volts), not their capacity.

**The capacity**

remains at 100Ah." (Emphasis added).

remains at 100Ah

I don't understand why a pair of 6v 100AH each, wired to produce 12 volts, only has 100AH. But, I don't need to know why. What's important to me is that one 12v 100AH battery costs less than two 6v 100AH batteries. Either option gives me only 100AH. And, as the Kolbus article notes, if I have more than two 12v batteries, I'll need to connect them in parallel so I don't end up shooting 24v into my TT.