>> I am assuming that “heating the battery” is in there so that it will simply charge faster, not that it won’t charge at all.
Apparently later Model 3’s have Lithium Iron Phosphate (LiFePO4) battery chemistry.
If you charge an LiFePO4 battery below freezing, it’ll permanently damage the battery. Therefore the battery management system on LiFePO4 batteries typically disallow charging below freezing.
The obvious remedy for an “all weather” solution is to install a heater in the battery (which of course takes power to operate, but that’s a subject for another time).
I imagine the heaters and battery temperature sensors are distributed throughout the vehicle just like I understand the battery cells themselves are. That’s potentially a LOT of heaters and sensors that must work correctly before the BMS will allow the battery to charge.
LiFePO4 batteries have a lot of advantages over other chemistries — for one thing, they’re inherently safer — but inability to charge at low temperature is one of the drawbacks.
https://www.caranddriver.com/news/a38414682/tesla-new-cheaper-battery/
Logic should read ..
Drain battery by powering battery heater until battery temp reaches safe charging temp. But a quick drive to a supercharger can undo that temp REAL FAST.
Draining a Lithium battery below 32F does not appear to damage it, only charging it below 32F
You see, this is why I enjoy FR and return to it year after year.
There are always people on here who are more knowledgable about some subject than I am, and I learn something nearly every day, so thank you to both of you.
Once in a great while, I get to return the favor on this.
I have a background in Chemistry, so the claim they wouldn’t charge at all was suspicious to me. I just assumed it would be slower.