Hi, I have been having all sorts of problems with my Galaxy Tab 10.1 not charging properly and having the red x on the battery icon. Tried pressing the on/off and volume buttons together which did seem to fix it - but as soon as the tab was unplugged and plugged back in the red x came again. If the battery drained right down it was almost impossible to bring the tab back to life. I even bought a new battery as I thought the battery must be duff.... no. The problem was with the charger. The Tab and Note use a TWO AMP (2A, 2amp, 2Amp) charger. I was using the plug from my S3 phone with the tab lead. I looked at the small print on the plug and it's a one amp (1A, 1amp, 1Amp) plug. I had muddled up my plugs and leads. Hunted around for the original 2amp plug and YAY! Immediately got the green battery charging icon, was able to switch the unit on easily and it is charging away now with a white lightning icon. Save yourself a massive headache - check you are using a two amp charger or that your charger is working properly. I really hope this helps someone else. Good luck.