The charger can not keep up and charge the battery while the computer is on. Granted there is a problem with the battery, but the original charger, which still works, charges the battery when the computer is on (as well as off).
It worked perfectly as soon as I placed the order. (No, not when it arrived, I mean when I placed the order) "How?" you ask. I was having trouble with the existing adapter -- the battery just would not charge. So, in desperation, I ordered this one. (used a different computer) When I returned to the laptop an hour later, the battery was fully charged! Now THAT's good performance!