InTerra SmarTarget┬« units are designed with a built-in Li-Polymer 3.7V 2000 MAH battery which should easily last for many charges over the life of the unit.  The powered seven-port USB hub included with the SmarTarget Kit is the preferred charging source and can easily handle charging five units simultaneously.  Additionally, there are ports for charging phones or other USB devices.  

To use the charging system, be sure to connect the hub with the charger directly to a standard 110-volt outlet.  Using only the USB to PC connection will not charge the units.

SmarTargets are designed so that while the unit is plugged in through the USB interface they will not activate the GPS to get a location or write data into memory.  Fully charged each SmarTarget should run more than 12 hours.