I left the LEAF at the airport Park and Fly for two nights without realizing it was going to get really cold! If you haven’t heard, the Leaf battery will freeze solid if the temperature hits -25C, and no electrons will pass through the frozen electrolyte. To prevent this from happening, the Leaf has a 300 W battery heater that kicks in when the internal battery temperature hits -20C, stopping when it reaches a more comfortable -10C. The energy to power the heater comes from the battery itself, so in theory, you can lose a significant portion of your charge simply by parking the car during a long cold spell. That’s why you should leave it plugged in when parked in the winter, which clearly wasn’t my case as the Park and Fly doesn’t have any charging points.
The first night hit -23.2C and stayed very low for several hours, while the second night wasn’t so bad as the temperature stayed above -20C. I kept monitoring the charge using the GreenCharge app on the iPhone, but it didn’t change at all. I was curious to see if there was any change in the SOC% so I uploaded the data from the C5 logger to the FleetCarma portal and checked. For the two nights, the state of charge only dropped 1.2%, from 57.4% to 56.2%, which proves that a few degrees below the -20C threshold is still not enough to make a dent.