i've got the same problem but it's the battery that won't hold it's charge

but for the price of a battery and shit it was just as cheap to buy another cordless, this time i went from a 12V and an 18V to a 24V, and the difference is fairly substantial

on that note, both my 12V and my 18V shared the same battery size and fitment, but they came with 2 different chargers
if i put the 12V into the 18V drill it was much slower and felt less powerfull, but by putting the 18V battery into the 12V drill, it seemed to feel as if the battery was way to powerfull for the drill, it was much faster to spin p, had much more torque to drive the screws in, but felt the same as putting a V8 into mini, just a bit wrong