Designed for use in leased EV applications where roof beacons need to be run all day but the base vehicle does not provide any continuous power supply. 

In this case the fleet controller did not want the base electrical system vehicle interfering with in any way. The 20Ah capacity of this small power system allows for a full days use and is then recharged outside the vehicle using the charger. All parts of the system are house din a rugged case including the mains power charger, battery monitor and socket outlet.