Do you have one of those J.P. ?

Looks like the Battery Tender version has the most reviews and comes with a charge controller to prevent over charging.

That Champion will run you out of the camp ground or your truck!!

I can't remember the brand of mine, but it's just like the Yamaha. I think the Honda's or Yamaha's are the way to go.

One thing to think about is be sure you have enough peak power to fire up your charger.

I stayed at a house in Arkansas with a dock down the hill and no power on the dock. He told me not to worry about it as he had a small generator I could use. I'm sure glad I took my own because his would not start my on-board charger up. So I took mine down to the dock and used it. I would have been totally hosed on that vacation because I was no where close to a boat ramp and it would have take an hour each day to launch and load for where I would have had to drive to.

Another option that's less desirable is to take batteries out and charge where you are staying with manual chargers.