My BEC poofed a few weeks ago, so now I'm using a 6V lantern battery. It's a bit heavy but traction is awesome, and I expect to get about 6 months of hard rx/servo use.
For my next trial, I'll be looking at one of those olschool bicycle headlight generators that rub on a wheel, I figure with enough steering trim it should cancel out the pull.
Mine just died, but i don't know if it was the problem. First the steering servo stopped working. I replaced it and checked my bec voltage 5.4. So I went to run it again and in about 2 min the bec died. So I strapped on a receiver pack. Tried again, within a min no steering again. Another servo later and now I have no response from the esc.