ASUS Ai Charger is your answer..
by Rider3 - 11/22/12 7:03 AM
In Reply to: iPad 3 charging problems using a windows based machine by rjlear
Google ASUS Ai Charger.
I used it to charge iPad 3 on a Win 7 PC. Will charge the iPad on or off.
I also use it for iPhone 5 when I'm in a hurry.
It works and it's free.