One Battery..or Two?

Two 6 volt batteries in series, double the volts, amps remains the same.

True 6 volt golf cart batteries ( TRUE DEEP CYCLE), offer MORE amp hours than a 12 volt RV/Marine battery. There are very few 12 volt TRUE DEEP CYCLE batteries on the market, and they cost a fortune.

I looked at (briefly) the lithium ion (iron) RV batteries, wow, sticker shock. They have some serious advantages over wet cell batteries. They can charge quicker, have very high discharge rates, can be fully discharged at their full rate until they give up (they are internally protected from being depleted too low, which hurts them), and they can be charged to 100% again with no sulfation/memory problems. They are also MUCH lighter for the same amp-hour rating as a wet cell. They do not out gas, making them good for inside installation.

They do get derated in colder temperatures, but all batteries do.

I'm currently looking at getting to Trojan T-105 batteries locally, because the Costo, Sams, don't carry a comparable battery, and shipping instead would be almost as much as the batteries themselves!! i think $200 each is not too bad for a price.

 My example:   (2) Interstate HD24-DP 12 volt batteries in parallel. The RC (reserve capacity) of these dual purpose (starting / "deep"cycle) batteries is 200 minutes at a 25AH discharge rate. That is double the 100 minutes of only one battery alone.

But two Trojan T-15 batteries in series at 12 volts, delivers 447 minutes @ 25AH. One 6 volt is 447 minutes @ 25AH. The two 6 volt batteries have more than double the reserve capacity, are only a little taller, and weigh a bit more, but have MUCH more energy density. And they can be more deeply discharged and last longer than the dual purpose batteries. Properly maintained (distilled water, and desulfation charge cycles when needed) can make them last 6-7 years. If you don't let your batteries get low on water, and don't deeply discharge them, they can last a long long time.

The downside. Up front cost. Takes longer the charge them to 100%. More tongue weight (which may not matter depending on tow vehicle).