The Range Device does NOT draw much on the vehicle battery during normal operation. If you drive your vehicle daily (or almost daily), then this will not be a concern. However, if you drive your vehicle infrequently (i.e., only on weekends), please remove the device. It is best practice to remove the device if your vehicle will sit for anything longer than 3-4 days.
To add some more detail:
- The device will go to a VERY low "sleep" state after the engine is off (within 3-10 seconds of the engine shutting off)
- In this state all the LEDs are OFF and it hibernates at about 1-3mA
- Every 7-15 seconds it will wake up to a "light sleep" state to check to see if the vehicle is running. In this mode, there will still be NO LEDS lit but current draw will spike for < 0.1 sec to about 7-10mA.
- If the vehicle is NOT running (i.e. RPM < 500) then it'll go back to deep sleep. Rinse and repeat until the vehicle is running, at which time it'll fire up completely and you'll start seeing LEDs light again.
Given this and the normal draw from other modules (a modern vehicle will always have a small draw for the security systems, BCM, remote start/locks, OnStar, etc. .. sometimes as much a 50mA), it is recommended to reduce the risk of battery depletion by unplugging the module when the vehicle is going to be sitting for an extended period. Cold weather, weak charge state, age, etc. can all contribute to less battery capacity.
A healthy battery with decent capacity should be able to go much longer than the recommended length of time but it worth it not to come out from a 2 week vacation and find the battery dead in the airport parking lot!