I have an old generic car charger. if I use navigation and stream music the battery percentage will just about break even, it wont charge but it wont discharge either, give or take 1 or 2 percent. I want to get a charger that will actually charge it like it did on my previous DroidX. On Amazon I see some chargers are 1amp and others are 2.1amp. I want it to charge but I dont want to cook it either. Which one should I choose? if it matters, I do not use the car dock, just a generic dash cradle and the charger is plugged directly in the phone. Thanks