The Emergency Rescue Boats USB Charger for the 7.2V 1000mAh NIMH Battery. This USB charger can be plugged into any USB Port that is no more than 5V at 2amps output. Computers, Surge protectors, TVs, Wall adaptors. Do not use any wall adaptor that is more than 5V at 2amps, some newer tablets have a 7.5V wall adaptor, and it will cause this USB charger to protect the battery by shorting a circuit in the charger causing it to melt a bit.
When plugged into a power source its Red charging light will remain off. Then a depleted battery is installed into the USB Charger and a Red Charging Light will come on. When the Red Charging Light turns off, the battery is fully charged. This USB Charger should charge a battery to about 8.4V fully charged.