A reminder about this type of charger for this power driver; don't leave the spare battery roasting in the charger. Design of this charger happen to have excessive trickle charge to keep battery topped up is crude. I ended up with GOOD 7 years old battery like new and one equally 7 year old spare battery roasted giving noticeably poor capacity. The habit was like this:, Best battery was one I charging up while I use roasted battery pack in the power driver then foolishly swapped battery packs again right away leaving the roasted battery stew in the charging cradle while I use good battery for couple or three days.
Once finished charged up, just take battery pack out of charging cradle. You'll end up with two good battery packs for years.
Cheers, Jason