A:Answer Most rechargable batteries are 1.2 volt DC. Similar in size to AAA'S. Two together would be 2.4 volts, 3 together 3.6 volts etc. It's the amp hour rating that's important, as they differ. The higher the amh the longer it'll last. Also the small terminal connector (plug in) has to match your phone. Make sure the polarity (positive on positive negative on negative) is correct, on the terminal plug in.
