Trevor, the best way to determine if a batt is charged is to test it after it's charged and see what's in it. You can discharge it by using a small light, like a light bulb for the blinker of your car, just stick wire into the batt plug and tape them to the terminals of the light and let it go dead before you recharge it. or you could just turn your TX on and leave it on and see how long it takes it to die out, just use the controls while sitting there watching TV so it trys to send a signal, or go into the programming mode, that seems to use batt power pretty quick. Also it is important to cycle your batt about 3 times before you use it anyway. this helps it build memory for charging