RV Battery Charging at Home

Hey Doc, I have bought two six volt batteries. My problem is that I have to store the trailer in a lot with no access to electricity. So I bring the batteries home to be charged. My question is what battery charger should I purchase to recharge at home. Also what amp should I use to recharge. Thanks and I always enjoy your presentations in Seattle. Mike A.

Mike, it’s probably better actually, to bring those batteries home to charge. That way you can monitor the charging process and keep a watchful eye on the electrolyte much easier. Simply connect the two batteries in series (one cable running from the positive post of one battery to the negative post on the other battery, and simply use any applicable battery charger to the other two posts. In this diagram, the battery charger would be connected to the same terminal posts as the two loose cables.

To fully charge both batteries, I recommend a multi-stage battery charger (such as the Xantrex TrueCharge2) and remember to never overcharge them beyond the gassing point. A computer-controlled battery charger will accomplish that automatically. The charger should be sized C/5; meaning, divide the total amp-hours of the battery bank and divide it by 5. That would be the recommended minimal charging unit required. As an example, two six-volt batteries in series would yield approximately 225-amp-hours. Divided by 5 = a 45-amp battery charger would suffice. I would recommend a 50-amp charger in case your batteries can store a little more than that.