Vehicle key-off load monitoring

A method of monitoring a fleet of vehicles for excessive Key-Off Load (KOL) current drain while in a Key-Off state, the method comprising the steps of:

• selecting a plurality of test vehicles which are operational without any anomalous current drain;
• identifying a plurality of time intervals according to a plurality of predetermined KOL modes which are activated successively after initiation of the Key-Off state;
• measuring Key-Off interval currents during each of the time intervals in each of the test vehicles;
• determining a respective average current of the interval currents in each respective time interval;
• determining a respective standard-deviation current of the interval currents in each respective time interval;
• setting a respective current limit corresponding to each time interval according to the respective average current plus a respective incremental value determined according to the respective standard-deviation current;
• transferring the respective current limits to each vehicle of the fleet of vehicles;
• measuring Key-Off interval currents during each of the time intervals in each of the vehicles in the fleet of vehicles;
• comparing the measured Key-Off interval currents to the respective current limits to determine respective Key-Off load scores for each vehicle of the fleet of vehicles;
• combining Key-Off load scores from the fleet of vehicles;
• and
• detecting an abnormality of the vehicles in the fleet of vehicles when the combined Key-Off load scores exceed a predetermined threshold.

A vehicle comprising:

• a battery configured to supply electrical current during a Key-Off state of the vehicle;
• a plurality of electrical loads each configurable to receive the electrical current flowing from the battery during the Key-Off state depending upon predetermined Key-Off-Load (KOL) Modes active according to respective time intervals;
• a battery monitor measuring Key-Off interval currents during each of the time intervals;
• a controller configured to (1) compare the measured Key-Off interval currents to respective current limits, and (2) indicate an excessive current drain in response to one of the measured Key-Off interval currents being greater than the respective current limit;
• wherein the respective current limits are obtained from:
• selecting a plurality of test vehicles which are operational without any anomalous current drain;
• measuring Key-Off interval currents during each of the time intervals in each of the test vehicles;
• determining a respective average current of the interval currents in each respective time interval;
• determining a respective standard-deviation current of the interval currents in each respective time interval;
• and
• setting a respective current limit corresponding to each time interval according to the respective average current plus a respective incremental value determined according to the respective standard-deviation current.