I just shaved down the 24v Allegheny battery and stuck it in the 18v Coleman charger. The Allegheny battery goes with the original Allegheny set - drill, circular saw, jigsaw, and light - that I have been running on the Coleman 18v battery. They all seem to work OK on the 18v Coleman. But I want to see if the Coleman 18v charger will charge the Allegheny.

After I shaved/fitted the Allegheny into the Coleman charger both the red and green lights came on and I seem to be charging the Allegheny. Will know at 8:30 tonight. Will report back.

Interesting - at first only the green light came on. I shaved it a little more and pushed it farther into the charger and both lights came on. So charge city for now. Pics below show the Allegheny battery stuck in the Coleman charger. Other pic is the Allegheny set.