LeftieBiker said:
The 300 watt battery warmer isn't mythical by any means. It has been well documented, starting from when Nissan began to include it with the heated seats and steering wheel in late 2012. You are apparently visualizing it as turning on when the air temp reaches a certain number, and then staying on for days. It doesn't work like that. The warmer turns on when the pack (not the air) temperature reaches something like 7F. That can take several days if the daytime highs get up into the mid twenties or higher. It then turns off when the pack temp goes back up to something like 11F, IIRC. As for noticing the consumption, we sure did and do. My car, when parked out in the cold wind by the Hudson River, would take about 2 days to turn its warmer on, but would then lose about 20-25% SOC a day until it switched off again. I left it plugged into L-1 under those conditions when possible.
Your consumption data sounds reasonable and consistent with pack heating.
I agree with your description of how the heating would work, that is why I said
up to 300 watts * 24 hours per day just for heater use and not including the energy cost of keeping the car awake during heating. When the ambient is -20C or so, heat loss is right around 300 watts. You did not see the maximum 24 hour energy consumption because your locale is not cold enough, for long enough. And few places in the US are, outside of unusual extreme weather events like we had last week.
Now we know thanks to Gerry that the 40 kWh LEAFs in the US, and all 62 kWh LEAFs, do not have a pack heater of any sort. So it is not possible for these cars to hold the pack temperature during a cold spell, or to heat up the pack prior to charging. And Kyle's video shows that the LEAF will send 5.2 kW to a pack that has been cold-soaked in ambients of -10F --- -20F for two days. Is that enough time to say that the pack was at ambient ? I'll guess yes, but others may have data or experience. The thermal transfer kinetics are not physically different than the copious reports of how long it takes the battery to cool down after over-heating in the summer, although the calcs have to be converted to Kelvin.
My earlier comments hold: US LEAFs from 40 kWh and newer are vulnerable to Li plating during charging in very cold weather, and the onus of prevention is on the consumer. Canadian 40 kWh LEAFs can be better, since the pack is unlikely to cool beyond -1F or so if connected to shore power or have a high enough SoC. No help for those who park on the street or are unaware of the SoC requirement, but who cares about them ? I wonder if 0.13 C rate in a -1F pack is Li plating territory at 90 - 95% SoC. Canadian 62 kWh LEAFs are as vulnerable as the US variety.
If I owned a LEAF without a battery heater, I would not use delayed charging in very cold weather. Heck, I don't even use delayed charging in my Bolt in our moderate winters, and it has pack thermal control. But I am obviously very cautious in this matter, in part because I charge at 9.6 kW.
