I have used this when using the iPad (and obviously had it plugged in) and it still runs the battery down, just slower than it would have otherwise. It is ok but there have got to be others out there that will work better. I mean, Belkin makes some great products but this is not top of the list. I use it and its ok but I would really like to find a 10 foot iPad cord that actually works and not rely on thsi thing. When your computer is plugged in, it should not run down to 70% when being used. So, based on that...I consider this product kind of a failure and the only reason it gets 2 stars is that I actually do use it