I used my old razor charger for my eris. Everything was fine until my phone started shutting off all they time by itself. Some times the phone wouldn't even turn on without plugging the phone onto the charger. At first i thought maybe it could be a bad capacitor on the circuit board so i demand Verizon send me a new phone. I got the new phone that came with out a new battery, forcing me to use the original battery that i used on my dysfunctional phone. I found out minutes after i put the battery in the new phone that it was doing the same exacting thing. Thous meaning my theory was wrong and the battery must be the source of the problem. I then decided to check the charger i have been using for about a year. It's amp output was 850mA. I don't have a electrical degree of any sort but i'm guessing that if you don't charge the battery with the right amount of Amperes it could in the future can cause battery failure. Hope this helps.