Possio Tracker charges when the vehicle is being driven and consumes a small amount when not in use. The amount of actual power consumption is very much dependent on what settings you use (GPS location updates when sitting still should be kept at a minimum for example) but as a guide:
1mA 12V (Sleep Mode) - COMING SOON
8-12mA 12V (Power Save)
100mA 12V (Active Tracking)