You got a peak charger? If so, dispose of the wall charger and charge the battery(s) with the peak charger...keep an extra battery charged and ready to go in your box.

Charging depends on what type of battery came with it...NiMH or NiCD. NiMH you don't have to discharge before charging, you can "top it off" The rate of charge of the wall charger is so small, you can leave it on for days without worry.It is a trickle charger.