HELP!!! Why is my Samsung Galaxy Tab 2 10.1 not charging?

[AC Question]

I purchased my tablet from a previous owner, so it wasn't brand new. I don't think the cable I have is the original charging cable and as for the usb port, I used my old iphone belkin usb port. I experienced the red x on the battery indicator when charging my tablet until one day I decided to used a different usb port (samsung usb port for galaxy 3) and the red x went away and my tablet charged perfectly since then. Now i have encountered another problem, my tablet now indicates that its charging but it's actually not. It discharges. I always powered off my tablet to let it charge and normally would not let it get below 10%. I don't know what's wrong now, I've been going through this for 2 weeks now. I let the tablet completely drain and let it sit on the charger for at least 12 hours and it's only on 1%. Just 2 days ago, I did the hold power button down until the tablet power off on its own and immediately plugged in the charger. The tablet then rebooted itself and showed 36%, but would charge pass that point but continue to discharge. Now it's back to where it was before, on 1% and won't charge anymore.

 

[Rukbat]

You shouldn't let it go below 40% for maximum life. Letting it go down to 10% gives you about half as much life as charging at 50%.

As far as which port you're charging from, as long as it's capable of supplying at least as much current as the phone will take, it doesn't make any difference. But most computer USB ports aren't capable of supplying more than about 400mA, and the phone can draw more than that, so I'd use a Samsung charger, or any charger capable of an output of 2 Amps, not a USB port.

Turn the tablet off. Plug in the charger. Let it sit, charging, for 24 hours. Unplug the charger and try turning it on. If that doesn't do it, you probably have a battery that's reached the end of its life.

Now i have encountered another problem, my tablet now indicates that its charging but it's actually not. It discharges.

It's not indicating that the battery is being charged, it's indicating that the tablet is drawing power from the charger. If the tablet is using more current than it can draw from the charger (the maximum current it can draw is determined by the circuit in the tablet , as long as the charger can supply at least that much current), the battery is being discharged to make up the difference. (IOW, if the tablet is using 500mA and it can draw 400mA from the charger, 100mA is coming from the battery, slowly discharging it.)