Vehicle battery saver mode automatically shuts off your detector after 3 hours if you forget to turn it off. The timer is reset if the detector is unplugged, turned off or any button is pressed before the timer has expired. The detector will alert you with an audible and visual warning (text units display "PWR OFF") before shutting off. Units with option select mode can turn this feature off. Most detectors draw around 300mA of power or just over 1/4 of an amp. When the vehicle battery saver kicks in, this power consumption drops by 90%.
What does this mean to me? Well let’s assume that the radar detector is left on and the vehicle's battery has a 60 amp/hr rating (average sized battery). The above vehicle would have a dead battery in about 200 hours or approximately 8.3 days. Roughly the time for an 2 week vacation or company trip. Having a detector with a Vehicle Battery Saver feature will extend the battery life to about 2000 hours or 83 days making the travel home from that company trip a stress free one.
Note: These times are approximate and do not take into consideration the normal battery drain from the vehicle's electronics.