Software update 2021.4.11 Cold Weather Improvement [Scan My Tesla log]

[pt19713]

I didn't think I'd be able to test this out until next winter but woke up to 24F temps and fired up the Scan My Tesla app to test the cold weather improvement update, 2021.4.11.

Below is a graph showing a ~ 44 minute drive. Ambient temp around 34F. Cabin heat set to fan speed 1 at 68F. Seat warmer 1. 2020 LR AWD Y with acceleration boost, Sport mode (but driving fairly efficient). Autopilot set to 66 mph once on the highway, minimal traffic, drive distance around 65 miles, mostly highway with a small portion at around 35 mph.

Lots of stuff to see here but the main thing to look at is the bottom portion of the graph and the purple line. This is the battery pack temp. It's pretty much flat. It was 58.1F when I started the drive, 57.2F when I finished. What does this mean? It doesn't appear the heat pump is scavenging heat from the battery pack to heat up the cabin. On previous drives in the same temps and conditions, the battery pack would be around 51-54F, with a wider range of fluctuation of temps. Another note, on previous software, I'd see the battery inlet immediately drop from 54F to 47F when I turn the cabin heat on. No drastic change with 2021.4.11. Once my cabin temps were reach, the battery inlet temps were rock solid. Overall, a pretty good update and I expect Tesla to continue tweaking it for cold weather.

 

[acarney]

Interesting, this might explain why some people have said that regen doesn't ever seem to get strong in the cold. If the heat pump is constantly cycling heat out of the battery as the cabin needs it, that's keeping the battery temps low, or even possibly dropping it lower from time to time.

On the flip side, that cabin heat is coming from somewhere, and if it's not pulling from the battery waste heat, it's pulling energy from the battery.

 

[mark95476]

The rear stator temps are high so it could be using some heat from there.

Tesla probably did some heat-pump efficiency testing and might have found that pulling heat from a huge sink like the battery during cold temps wasn't the best overall. People generally aren't gunning it hard in winters so there's not a lot of left-over heat for the battery.

It'd be interesting to see if this changes as the battery runs down to 0%. The battery would be warm so you can pull heat from there and don't care about keeping it warm. I recall Bjorn having a recent video where he shows the Tesla shutdown steps in a M3.

Interesting, this might explain why some people have said that regen doesn't ever seem to get strong in the cold. If the heat pump is constantly cycling heat out of the battery as the cabin needs it, that's keeping the battery temps low, or even possibly dropping it lower from time to time.

On the flip side, that cabin heat is coming from somewhere, and if it's not pulling from the battery waste heat, it's pulling energy from the battery.

 

[mark95476]

Just remembered something...

Bjorn saw that new 2021 M3s with the heat-pump would extract heat from the battery so much that it'd be come dangerous with no acceleration. So you could be on the freeway trying to do 90, but couldn't until because it was power limited. I think this was applicable for M3P with supposedly larger battery and higher-end Panasonic cells.

 

[Barrygold]

I didn't think I'd be able to test this out until next winter but woke up to 24F temps and fired up the Scan My Tesla app to test the cold weather improvement update, 2021.4.11.

Below is a graph showing a ~ 44 minute drive. Ambient temp around 34F. Cabin heat set to fan speed 1 at 68F. Seat warmer 1. 2020 LR AWD Y with acceleration boost, Sport mode (but driving fairly efficient). Autopilot set to 66 mph once on the highway, minimal traffic, drive distance around 65 miles, mostly highway with a small portion at around 35 mph.

Lots of stuff to see here but the main thing to look at is the bottom portion of the graph and the purple line. This is the battery pack temp. It's pretty much flat. It was 58.1F when I started the drive, 57.2F when I finished. What does this mean? It doesn't appear the heat pump is scavenging heat from the battery pack to heat up the cabin. On previous drives in the same temps and conditions, the battery pack would be around 51-54F, with a wider range of fluctuation of temps. Another note, on previous software, I'd see the battery inlet immediately drop from 54F to 47F when I turn the cabin heat on. No drastic change with 2021.4.11. Once my cabin temps were reach, the battery inlet temps were rock solid. Overall, a pretty good update and I expect Tesla to continue tweaking it for cold weather.

View attachment 647085

great info. Thanks for sharing