I don't have a whole lot of experience with the newer lithium power tools. I have a couple of pieces of a discontinued mastercraft maximum series. The impact driver has been very good so far though, and I don't charge it as often as I do the older makita or mastercraft drill. I haven't taken on a project with it yet though. I got it after I renovated the basement.

Anyway, your situation doesn't sound right. Either you've got a dud drill or battery from the store, or there are other problems. I'm curious as to why you're using a forstner bit though. If you're going through studs, a holesaw would be a much better idea. Forstner bits in my experience are good for flat bottom holes, like you would for a cabinet door hinge. They "bore" out the entire hole, so, for the most part, they're good for if you want a hole that doesn't go all the way through. Holesaws only cut the outer edge, so its only useful for going all the way through, like you would for holes for pipes. Stresses the drill a lot less than the forstner bit for sure!

Maybe that'll help, but I'm still a bit suspect if its having trouble like you say =/

.dk