Managing Power

Managing power on an Auto PC is complex, due to several factors:

• Because an Auto PC continually draws current from the vehicle battery, the battery may discharge if the vehicle is unused for an extended time.
• Voltage normally drops when a vehicle starts.
• A vehicle battery may fail or be disconnected.

To manage power successfully under these conditions, an Auto PC uses two power sources: the vehicle battery and a backup battery. The vehicle battery operates an Auto PC on a regular basis. A backup battery provides enough power for an Auto PC to shift to a power off state and to maintain the contents of dynamic RAM (DRAM) in that state. A backup battery is not intended to operate an Auto PC when the vehicle battery is in a low power state, and can only support the normal state of an Auto PC for a short period of time while the backup battery shifts an Auto PC to a power off state.