On Fri, 05 Apr 2019 09:16:02 -0700, Jeff Liebermann
wrote:

On Fri, 5 Apr 2019 00:58:45 -0700, Mike S wrote:

I was given an electric drill that uses 12V lithium ion batteries
because the charger didn't work and the batteries died and the owner
lost interest.

The photo is NOT a LiIon charger, which would include an IC to control
the voltage and current to the battery.

Perhaps it might be useful if you would disclose the maker and model
number of the drill and charger? The battery type could then be
easily researched.

It is possible to convert a NiCd or NiMH drill to operate from a LiIon
battery. Is this what the former owner has done? If so, you will
need a much better LiIon battery charger designed specifically to
charge a LiIon battery.

I bought a new NiMH battery for my RC car.
7.2 volts 3500 mah. Would it do any harm to try to charge it
with a small plug pack charger made for use with NICAD?