I'd watch out for the non-OEM chargers. I had a Nextel i90 (the cousin of the phone that beat the 7135 in that march madness thing, although I think that was a mistake), and I bought a cheap aftermarket charger. After about two months or so, my phone could no longer charge, even with another charger (suggesting the phone itself had a problem). I took it to a store, told them nothing about a car charger, and after not very long the guy identified that the heads on the phone were damaged from shaking, often caused by an aftermarket car charger juggling around through the natural bumpiness of driving causing a slow erosion of the heads. I had to go three months with only stand-alone battery charging. I know with two batteries you probably charge them stand alone anyway, but for travel and other purposes, you don't want to break the charging heads on your phone. Just a heads up.