Battery Power down to 20 mins at 100%

[carnageX]

But could you still use the laptop w/o the battery, just the AC?

Yes, you can. I do this allthe time with my laptop, cuz I don't need the battery in it all the time.

 

[Nitestick]

you don't necessarily have to replace it with the same model battery. the battery does of course have to be designed for your particular model/series of laptop. if it is the correct form factor and voltage you may use one with a greater mAH rating.