I bought 1600mAh battery and noticed that when charging the light on the charger would never turn green no matter how long I left it on charger and the battery would be dead before the end of the work day (8 hours). Even during those 8 hours I'm not using it too often and only using it at about 3.8-4.2 volts depending on the juice and with a mini nautilus tank. So I took it back to where I had bought it and they checked my chargers ( even though they charge all my other batteries just fine ) and they worked so they exchanged the battery and 2nd battery is doing the same thing. I'm using standard eGO usb charger that came with eGO starter kit and even bought a new charger and wall mount hoping that would fix the problem and it did not. I checked the security code on both batteries and they check out. I could understand one bad battery but not two and doubt it is my charger so decided to look here for answers before I give up and go with another brand cause having a battery that's supposed to last 16 hours die from 3 hours of use (if that) just doesn't add up. Thanks for any help in advance and hope someone can shed some light on what is happening.