That could be. If you use the 10 amp charge, it charges very fast. Even if it's half depleted battery, it only takes 3 hours to charge all 3 12v packs. Not too bad. Yeah because I think the B&D uses some kind of sensor to know when it should cut back on the current.

I can vouch that charging one 12v pack at a time definitely works long term because I'm on my 30th cycle now. I've went over 120 miles.