The charging protocol (how much voltage or current for how long, and what to do when charging is complete, for instance) depends on the size and type of the DD AA/AAA Battery Charger being charged.

Some battery types have high tolerance for overcharging (i.e., continued charging after the battery has been fully charged) and can be recharged by DD AA/AAA Battery Charger by connection to a constant voltage source or a constant current source, depending on battery type.