6 or 12

**BogeyBoyNevada** · 09-28-2019, 05:05 PM

We are going to replace our tired old 12 volter with two. Knowing nothing about capacitys, what is the best way to go: Two 12's or two 6 volt
Thanks!

**Cate&Rob** · 09-28-2019, 05:21 PM

Two 6V batteries in series will have more amp hour capacity. But, if you lose one cell in one battery, you lose all your 12V power. Two 12V batteries in parallel will have less total capacity, but you have "redundancy". If one battery fails, you can disconnect it and use just the other battery until you get a replacement for the failed one. I always go with two 12V batteries . . . just my opinion.

Rob

**BogeyBoyNevada** · 09-28-2019, 05:45 PM

Thank you-appreciated

**WhittleBurner** · 09-28-2019, 07:47 PM

What I did was I already had the 12 volt from when I bought the trailer. I bought 2 6 volt batteries and put the box next to my 12 volt. The wires reached and the only wire I had to get was the jumper to hook them up parallel. My 12 volt sits there not hooked up and I check it once in awhile to make sure it's still charged up. If I have a problem with the 6 volts i can switch it over to the 12 volt and not miss a beat.

**sande005** · 09-28-2019, 09:35 PM

When shopping, look for the words "Reserve Capacity" or "RC" in comparing specs. The higher the number, the longer the battery will last on a given load. Ignore "CCA" or "Cold Cranking Amps" - most true deep cycle batteries don't even have that rating. But batteries used for engine starting do. As a broad rule, the more CCA's, the LESS RC, and vice versa. You always want more "RC".
RC usually is higher in bigger battery sizes. There is no guarantee that you will get more with more $$. Ignore the hype - the RC number tells the tale.
6 volt batteries usually have a much higher RC, but even though you need two of them, that doesn't double the amount of RC you end up with - it stays the same as whatever one is rated at. With 12 volt, though, it does double. So two 12 volt batteries, if you shop carefully, can get moderately near (or even sometimes exceed) the amount from 2 lesser 6 volt batteries.

**jmbopp** · 09-29-2019, 08:19 AM

With 2-12V batteries if there's a shorted cell in one battery it will drain the other battery too. When it was time for new batteries I went with dual 6V ones.