Charging the battery with a generator: AC or DC?

[BobWilson]

On our last trip to Joshua Tree National Park we dry camped and used more electrical power because it was colder outside 30F to 40F at night during our 6 night stay) and preferred to be inside more. So I brought my Honda EM650 charger to charge up the battery. I plugged the TM's AC cord into the generator to charge up the battery the first couple of nights. Using the ammeter I installed, as recommended by Bill Jeffery, it measured 5 amps of charging with nothing else running on the TM. I wondered how accurate the automotive 20 amp ammeter is since the scale is so small.

I noticed that the generator had terminals rated at 8.3 amps at 12 Vdc expressly for charging a battery. So I made a cable from parts at an automotive parts store and plugged it in. I didn't have a way of measuring the charging current without modifying my ammeter set up. But I was wondering which is the best way to charge the battery. Faster is better, of course, from a time standpoint because you can only charge in that campground at certain hours of the day. And of course you have to be at your trailer to do it at those hours. So time is important. Charging slower is probably better for the battery in the long run. But how much current is too much? I have two Interstate 6v Deep Cycle batteries in series. What if I connected the 12 v cable to the batteries and plugged the TM cord also to use for lights and other appliances at the same time?

Bob W.