Submitted by docdac on January 14, 2013
It has been around 15 deg F in my garage for the past couple of weeks. I have found that my Model S battery will be cold in the morning and I will not have Regenerative braking for about 10 minutes of driving, even though I leave it plugged in all night at 240V (NEMA 14-50). I thought the battery was supposed to stay 'warm' while it is plugged in.
I have 4.1 software and use the 'sleep mode' where the displays are not powered when not in use. I wonder if the whole car 'goes to sleep' and quits warming the battery once it is fully charged. This might explain the cold battery, even though fully charged and plugged in. Could this be a quirk of the 4.1 software? Has anyone else noticed this.