Does the car charge to keep warm?

This past weekend I’ve noticed something kind of odd with my Focus Electric. The temperatures around here have been in the 20s; I keep the car parked outside (and, unfortunately, this time of year it is mostly in the shade all day too).

When I’ve plugged it in after a drive I’ve noticed it taking a very slight charge–not quite the large charge that the Level 2 can deliver (typically I see 1/2 the battery charged in 90 minutes). Today I monitored it for almost 5 hours after taking a short 15 mile drive this morning using up about 4 kWh of electricity.

Over that 5 hours of time the car consumed 3 kWh of electricity and the car did charge up to 96% charge (when it started it was somewhere around 80%). All this time the dash and the website indicated that the car was waiting to charge (its set to always wait until 1:00am to begin charging).

From this (granted not very scientific) experiment I’m suspecting that when the car needs to turn on the TMS it also turns on the charger to trickle charge the battery (perhaps even using the process of charging to heat the battery??). Very interesting indeed.

Note in the summer when I’ve monitored the car while it was waiting to charge the % charge remaining value always stayed the same over the course of the day (didn’t think to measure the power consumption at the meter though) so something different is happening when the car is cold.

 

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