Don't see why you couldn't. You'll have to work out a way of charging it however. It's non trivial to charge newer batteries.

The Li-Ion batteries in my Dell are rated at 14.8V @ 3800mAh so you should be able to get a few hours out of each battery at least. It's nearly 4x the size of a laptop drive however so finding a battery small enough but also with a large enough capacity for it to be useful will be the hard part.

- Trevor