Trouble charging when cold

[JonnyNY]

Hi guys, I have looked everywhere for information on this but I am not sure I've seen people with the issues I'm about to tell you all about. For background I have a 2020 M3 LR AWD with the 2020.40 software and I charge at home using a Test Wall Connector Gen 3 and at work I have a Chargepoint. I live in NY state where it's been in the 50's Fahrenheit in the morning lately. And I should say that originally the car seemed to charge/regen okay, but lately it has been a complete mess. So please read and "enjoy"

1. When I schedule a charge for the morning it basically doesn’t work at all. It maintains voltage but the amperage fluctuates and barely charges at all. You can see a graph from TeslaFi attached and this is labeled "cold scheduled" and is second image.
2. To test whether there was an issue with the scheduled charging, I also tested just normal morning charging. Had very similar results with constant voltage but fluctuating amperage and very little charging. This is labeled "cold charging" and first image.
3. However, when I return from work and plug into the very same charger and charge I am able to charge relatively properly. This is labeled "warm charging" and third image.
4. For comparison, when I destination charge at work after the car is somewhat "warmed" up it seems to work reasonably well. I have shown here a graph called "work charging" for that data and this is fourth image.
5. Even when warm, the car still drops amperage as you can see quite a bit during the charges at home and at work. I am not sure if this is normal behavior or not but when the car is warm it will charge reasonably as expected.
6. Lastly, even when the car is charging, it has no idea how long it will take to charge. This morning I was at work running at 6kW and 30 Amps. It predicted it would take 4 hours to get to 80% from a little less than 60%. However, 2 hours 45 minutes later it was done. Indeed, when it was at 79% it still said 30 minutes remaining even though it finished in just a few minutes after.
7. There is a related issue with regenerative braking. I am aware that it needs time to warm up but I can tell you that even after driving about 30 miles yesterday in about 60 degree weather I never got full regenerative braking. And I often see the dashed dots to the right as well, saying I have limited acceleration. This happened this morning. At dead cold I had full acceleration but after driving 11miles I saw that I had limited acceleration. Doesn't make sense.

Taken together, I suspect that my battery management is not properly functioning and this is why it won't charge when "cold", why it can't estimate length of charge, and also why it will not properly allow regen. It's because it "thinks" it's much colder than it is. Any help would be greatly appreciated.

 

[DirtyT3sla]

Pretty interesting. I don't have a concrete answer for you, but I'll do my best to give you some input to help out. I'm in Michigan for reference and have had my Model 3 since February 2019 with no charging issues. I charge at home using the NEMA 14-50 adapter.

At 60F you should not see charging slowed. It's just not that cold. Even approaching freezing, charging from the wall connector shouldn't be slowed much or at all.

You say it works after your drive to work... but have you tried charging at that charger while cold? How about using your home charger right when you get home when the battery is "warm" to try it out? It seems like you did try this out, but just making sure.

I say this because my guess would be something weird with your home charger and the temperature change is just a coincidence. Even in the dead of winter, 20F, my NEMA 14-50 will give me full 32 amps unless the car sits for over 24 hours without driving/charging. And even if it doesn't, it doesn't bounce all around.

As for 7, it's pretty normal for regen to never fully restore depending on the length of your drive. I will drive 80mph for 30 minutes in the winter, and my regen never fully recovers. I do find it strange, again, at 60F it didn't fully restore, but if you didn't drive fast/regen a lot, I can see it.

Hope some of that helps. Sorry I don't have a more direct answer for you.

 

[JonnyNY]

Hey, I've seen many of your YT videos (assuming same person). Thanks for your response and your content!

-I haven't yet tried charging while "cold" at work yet. I think that would be the next step. I get to work around 7:30am. I could try to charge there when it's time to leave after 8-9 hours and see. I hadn't thought of that. Good idea!

-Yes, I can easily charge at home after returning from work. No troubles at all other than it doesn't estimate the time remaining properly.

-I also have wondered about not driving fast- my commute is on small-ish, poorly maintained, and congested NYC and Westchester County roads. I think my average speed must be in the 40-50mph range and it's about 15 miles one-way. So it's possible that this is contributing to the regen issues. I am taking a small road trip this weekend and will drive about 100 miles each way on the interstate so I will use that to test the issues with regen.

Again, appreciate the response, and yeah it's a weird situation. Hope I can figure it out!

 

[Gasaraki]

Hi guys, I have looked everywhere for information on this but I am not sure I've seen people with the issues I'm about to tell you all about. For background I have a 2020 M3 LR AWD with the 2020.40 software and I charge at home using a Test Wall Connector Gen 3 and at work I have a Chargepoint. I live in NY state where it's been in the 50's Fahrenheit in the morning lately. And I should say that originally the car seemed to charge/regen okay, but lately it has been a complete mess. So please read and "enjoy"

1. When I schedule a charge for the morning it basically doesn’t work at all. It maintains voltage but the amperage fluctuates and barely charges at all. You can see a graph from TeslaFi attached and this is labeled "cold scheduled" and is second image.
2. To test whether there was an issue with the scheduled charging, I also tested just normal morning charging. Had very similar results with constant voltage but fluctuating amperage and very little charging. This is labeled "cold charging" and first image.
3. However, when I return from work and plug into the very same charger and charge I am able to charge relatively properly. This is labeled "warm charging" and third image.
4. For comparison, when I destination charge at work after the car is somewhat "warmed" up it seems to work reasonably well. I have shown here a graph called "work charging" for that data and this is fourth image.
5. Even when warm, the car still drops amperage as you can see quite a bit during the charges at home and at work. I am not sure if this is normal behavior or not but when the car is warm it will charge reasonably as expected.
6. Lastly, even when the car is charging, it has no idea how long it will take to charge. This morning I was at work running at 6kW and 30 Amps. It predicted it would take 4 hours to get to 80% from a little less than 60%. However, 2 hours 45 minutes later it was done. Indeed, when it was at 79% it still said 30 minutes remaining even though it finished in just a few minutes after.
7. There is a related issue with regenerative braking. I am aware that it needs time to warm up but I can tell you that even after driving about 30 miles yesterday in about 60 degree weather I never got full regenerative braking. And I often see the dashed dots to the right as well, saying I have limited acceleration. This happened this morning. At dead cold I had full acceleration but after driving 11miles I saw that I had limited acceleration. Doesn't make sense.

Taken together, I suspect that my battery management is not properly functioning and this is why it won't charge when "cold", why it can't estimate length of charge, and also why it will not properly allow regen. It's because it "thinks" it's much colder than it is. Any help would be greatly appreciated.

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Very weird. I am also in NY and don't have your issues. DirtyTesla is right, level 2 charging at home is not really that fast and shouldn't throttle based on temperature at all. Now if you said that this only happend at home, I would have told you to call Tesla Energy support (the people in charge of supporting the wall charger). They are able to look at the logs of your gen3 charger and the logs for your car also. I know because I called them about my wall charger giving an error and slowing down after 20mins of charging at 48A. They were able to look at the logs in my car.

However you seem to have issues with the Chargepoint chargers also so I would schedule a service appointment and see what they say.

 

[jjrandorin]

I dont think you have any "regen issues". It takes a long time for the battery to get warm in a model 3 while driving. I live in southern california, park my model 3 in a fully drywalled garage with insulated garage doors, and it never gets above 85 degrees or below 50 degrees in my garage at any time of the year (even though it can be much hotter or colder outside.

My commute to work (when I was driving every day) is just under 40 miles. Every morning my car has regen dots, and I drive on a freeway in southern california that has a speed limit of 70 MPH and actual speeds if no traffic in the low 80s, and my car still has regen dots when I am 2/3 of the way to work.

Or, said another way (TL ; DR) driving at 80+ miles an hour for 20 miles is not enough to make the regen dots go away fully, even when it is 60 degrees outside). So, scratch the "regen dots" off the list as an indicator of some issue.

Your teslafi screenshots show you are charging at less than 20amps. What is your home charging setup, exactly? What plug / breaker, max amps etc?

 

[Gasaraki]

Hey, I've seen many of your YT videos (assuming same person). Thanks for your response and your content!

-I haven't yet tried charging while "cold" at work yet. I think that would be the next step. I get to work around 7:30am. I could try to charge there when it's time to leave after 8-9 hours and see. I hadn't thought of that. Good idea!

-Yes, I can easily charge at home after returning from work. No troubles at all other than it doesn't estimate the time remaining properly.

-I also have wondered about not driving fast- my commute is on small-ish, poorly maintained, and congested NYC and Westchester County roads. I think my average speed must be in the 40-50mph range and it's about 15 miles one-way. So it's possible that this is contributing to the regen issues. I am taking a small road trip this weekend and will drive about 100 miles each way on the interstate so I will use that to test the issues with regen.

Again, appreciate the response, and yeah it's a weird situation. Hope I can figure it out!

To check if the temperature is causing your regen issues, TeslaBjorn does something he calls "yoyo driving" to heat up the batteries. You acccelerate really fast then let go of the accelerator and let it do full regen, then accelerate real fast again and let go the accelerator. If the dots disappear after doing this for a bit, it's probably just a temperature issue with your dots.

 

[GtiMart]

Our batteries like to be warm. Full regen (85kW) only happens when the battery reaches around 20C (72F). Batteries are very slow to heat up. If the night was colder than 60F, your battery is colder too.

You can speed up your battery heating somewhat by heating the cabin with your phone app. The car will generate "waste" heat from the engines to warm the battery until you drive. It's the same process as the supercharger preheating.

Even when there are no dots on screen you might not have quite full power or regen but you are at least close...

Scheduled charging could be weird... There are known bugs and it plans for a 6am departure whatever you enter I think. I suggest you test normal charging without using planned departure. I cannot explain your down spikes of Amps. I don't believe I've ever seen that.