Why my tab can't use with out charger

VICKY BOY, the very first thing we need to know is exactly which Tab you have. Your description is a bit vague. Then I would suggest that you replace the battery and see if that will work. This will at minimum give you a better starting point for your problem. You can of course measure the voltages on your battery connector with your TAB plugged in to see what you get. If a new battery will not resolve your issues, check the power port to make sure it makes good contact. There is always the possibility that you have a bad PWM IC Let us know what you find, hope this helps, good luck.