I got a battery powered craftsman drilling machine from someone, the battery did not hold charge at all.
I have a few LiPo batteries left over from drones I don't use anymore, and I thought to put those to use.
I opened the 12V craftsman battery, and removed the battery cells inside, and wired a XT60 connector where I can plug one of 4 cell LiPo battery (it should be a 3 cell for 12V equivalent, but don't have a 3 cell one)
I used a 4 cell, 4000 mAh battery, but the casing is big, so you can use even bigger battery.
Of course you cannot use the craftsman charger anymore, you have to open the case, and plug into a proper charger for the battery you are using.