When I drive (which can be several hours a day) I charge my battery via the cigarette outlet. I bought a 10 foot extension on Amazon (with good reviews) to run it into the rear, not sure if the extension contributed. The battery draws about 120 watts, which I thought should be fine, since the fuse on the power outlet is 20 amp and the extension was suppose to have a 10amp fuse as well. Well, suddenly the battery stopped charging. Apparently too much heat and the contact point melted. I had to yank the thing out of the socket since it was melted into the socket. Apparently this also somehow cause the 20 amp fuse to blow. Replaced the 20 amp fuse and pulled out the socket. Cleaned it up a little and things seem to be working again (with a new extension cable). But the lesson is, be careful. Old timers will remember these power outlets used to be used to light up cigarettes. So I guess I shouldn't be too surprised that a constant 120 watt draw could heat things up too much and melt the cheap contact point metal.