Originally Posted by
Gail Lee I am having the exact same problem. In fact, if the tablet is not turned off completely while charging, it will actually LOSE charge when plugged in with factory issued charger. I have closed all apps running in background. Very frustrating! !
Loose charge when plugged in, your tablet is not charging: bad cable or bad USB charging port.
This tool will tell exactly if your tablet is charging, current should be around 1.5 to 1.7 amperes
usb current and voltage tester | eBay
Galaxy Tab 3 has different models and screen sizes, you have to be specific which model, otherwise I have no idea what is wrong with your tablet.
Tab 3 7.0, USB port is soldered to main board, but larger Tab 3, USB port is on Flex FPCB and it's easy to replace.
Most people doesn't know that charging problem of Tab 3 7.0 like 210R or 2105 can be fixed via newest firmware update.