Stop worring about your battery when using your 12V accessories and enjoy your trip instead, with the Projecta Battery Discharge Projecta making sure your battery will not be harmed from excessive discharge. Designed to turn off accessories before they discharge the battery, the ODP500 ensures the battery retains enough power for the next start. Once the ODP500 has turned off the accessories, they will stay inoperable until the vehicle's motor has been restarted for optimal protection!