Bout the same as the iPhone.
Seriously though, charging it in the car as I drive is just normal practice for me, was for the iPhone too.
I think any of these BIG screen devices with a Quad core processor is gunna get hit by the screen sucking up the juice.
My main battery drain today was screen and calls.
But don't let the battery stop you buying this device...it is soo sweet to use, I just love it!