I’m not sure what to make of this. Someone reported in the battery thread that the newest sw update seemed to improve this problem by lowering the voltage floor in coldish temps. My problem with all of this is that the 2021 seems to be underperforming the older car significantly after 70SOC. Is this JUST a cold weather thing and if so, what’s the threshold? And even IF it’s just a cold weather thing, why is this acceptable? I paid a lot of money for this car - why shouldn’t it perform at least as well as a 2018 model in all driving conditions?
I am not sure if the SOC limits are slightly different for different battery manufacturers - they probably are as there are reports of i.e. panasonic batteries performing better in the cold. But I don't think they'll be drastically different.
Like I wrote before, part of the issue is the heat pump which scavenges heat from the batterypack both during preheating as well as driving. Whereas older cars will actively heat the battery with 7.5kw until you are at warm temperature.
Treshold (for older Model 3s) are roughly as follows:
Cold: below 15Cish (batter heater on)
Warm: 28C ish (neutral)
Hot: 50C ish (battery cooler and fan on)
90% SOC you have 100% power when the battery is hot, 90% power when its warm, 75% power when the battery is cold.
70% SOC you have 100% power when the battery is hot, 70% power when its warm, 70% power when the battery is cold.
40% SOC you have 90% power when the battery is hot, 60% power when its warm, 40% power when the battery is cold.
at 10% SOC you have like 25% power when its cold.
For the newer batteries those power outputs particularly when its cold are lowered (for whatever reason) and you also struggle to get the car above the 15C limit if the heatpump constantly takes heat from the battery to heat the cabin.
I am gonna throw a wild idea into the room that Tesla is trimming their batteries more and more to prefer to be run hot and at 100% SOC (as evident by their iron battery chemistry which prefers to be hot and frequently charged to 100%).
The tradeoff is presumably cold performance. You cant have it all.
The other thing is that Tesla doesnt have much data on the new Model 3s so doesnt know how much damage the battery gets at low or high SOC from accelerating hard and regenerating. They got it wrong before i.e. with the old Model 3s which used to regen hard at i.e. 90% SOC at cooler temperatures. In January 2019 we got an update which limited regen unless the battery is above warm temperature. In fact from January to March 2019 regen was generally just a bit weaker. I remember that single pedal driving wasn't really possible at that time because the car just didnt regen quite enough.
Even when I leave in winter here in the morning (winter here is 25C) i get some limited regen at 85% for a few minutes until the battery goes above 28C which takes maybe 2-3min of driving.