I have an old model Storm battery 3.7V 650mA , recently it is not charging at all . I thought my charger was bad , it has an ouput of 4.2V 420mA , so I bought another charger from vapor king turned out this one has the same output as my old one and it doesn't charge my battery as well . I plugged it in to the USB port on my PC the green light on the charger lit right way , left it plugged in over night and still no power to the battery the next morning . How can I test/know if the battery is bad ?