I have a thread here discussing it. It’s to replace IMR’s I pulled out of a battery pack for my work tools.
I’m not sure exactly how the battery circuitry, or the charger for the drill operate, and can’t readily get the information, so I’m worried to use any other chemistry, although the thread discusses Sony VTC’s.
Thing is, I’m also trying to budget-build this pack….so price is a big issue. Trying to get increased capacity as well.