LUCAS Battery (Dark Grey LUCAS 3 device). The LUCAS battery is a rechargeable Lithium- Polymer (LiPo) battery which typically last for 45 minutes of operation. You can charge the battery quickly, less than 2 hours in the device if connected to the external power supply or car power cable, and less than 4 hours in the desktop charger. Compatible with LUCAS 3 and LUCAS 2 devices.