AC charging issue since 2020.44

[Zuikkis]

Schuduled doesn't affect it. Battery temperature is the key.

If car is plugged in right after driving, the battery is warm and charging will start normally.

But if you let the car cool down for some hours, then plug it in, the battery is too cold and charging is stopped and restarted every 5 seconds.

Scheduled charge is the same; if battery is too cold it won't work.

 

[fultonpub]

I leave it plugged in so its full before it goes to bed. In morning i come out and its flipping back and forth but only when its like 32 or colder.

 

[ccharleb]

Schuduled doesn't affect it. Battery temperature is the key.

If car is plugged in right after driving, the battery is warm and charging will start normally.

But if you let the car cool down for some hours, then plug it in, the battery is too cold and charging is stopped and restarted every 5 seconds.

Scheduled charge is the same; if battery is too cold it won't work.

This is exactly what I'm also experiencing. No problem if battery is warm/hot... not sure what is the threshold.

Can anyone confirm the error message associated with this problem from the car Notification Menu? I'm having BMS_w31.

Also, if I'm having the issu, I can trigger the charging session by turning on Heat inside the car (with the app) and turning it off after the charging session is working properly.

Christian

 

[PapaH67]

Also, if I'm having the issu, I can trigger the charging session by turning on Heat inside the car (with the app) and turning it off after the charging session is working properly.

This time of year, my garage is always in the 30's and the heat is on in the car always. Perhaps my opening the car door (and thus getting the cabin heater going) gets the charging set. My TOU costs are very high from 3 pm - 9 pm, normal from 9 pm to 11 pm, and cheap from 11 pm to 7 am. So I open the door at 9 pm (and that gets the heater going) and plug it in. Then the charging successfully starts at 3 am or so and I would guess that everything in the system is back to cold by then. If I don't open the door at 9 pm and just plug it in, it will fail. I never stay up late enough to plug it in at 11 pm to not use the scheduled charging.

 

[PapaH67]

Last night, I did the opening the door routine at 9 pm to get the heater going and plugged the car in after that. The Depart At time for charging should have started about 5 am, but it was cycling start/stop at 5:30 am when I got up. The garage temperature had fallen to 34F degrees, so it looks like cold temperatures are at least part of the problem.

 

[Rocky_H]

From people reporting that this is only happening in cold temperatures, and also reporting that if they use a lower amp setting that it will sometimes get it to work, I am forming the general outline of what is functionally happening here.

It sounds kind of like the logic in the car is broken of not turning on its battery heating routine. There is that curve of how many amps are safe for charging based on the temperature. It sounds like the car tries to start, but it detects that the amps are too high for the cold temp and cuts off. But instead of turning on heating, and waiting until it's warm or using less amps, it seems to be stuck in a loop of trying high amps, stopping, trying high amps, stopping, etc. without ever deciding to wait and warm the battery first.

 

[PapaH67]

From people reporting that this is only happening in cold temperatures, and also reporting that if they use a lower amp setting that it will sometimes get it to work, I am forming the general outline of what is functionally happening here.

It sounds kind of like the logic in the car is broken of not turning on its battery heating routine. There is that curve of how many amps are safe for charging based on the temperature. It sounds like the car tries to start, but it detects that the amps are too high for the cold temp and cuts off. But instead of turning on heating, and waiting until it's warm or using less amps, it seems to be stuck in a loop of trying high amps, stopping, trying high amps, stopping, etc. without ever deciding to wait and warm the battery first.

I have TeslaFi running since 850 miles on my car. I looked into the data that the charging log puts out and I am still busy collating it. Basically, mine appears to have started this back on August 22, 2020 on build 2020.32.2. I'm only up to September 2, 2020 and build 2020.36 is still exhibiting the behavior. I'm not sure temperature is a factor unless heat is bad too. The temp log says the car is 76F to 90F so far. I'll post more later. This will take some time...

 

[ccharleb]

Tesla Mobile told me that there should be a fix on 2020.48.12 ... I'll wait and see!

For me, battery temp seem to be the key point, not outside/inside temp of the car. Seem to have started when temps went below freezing, end of October. At that time, I was on 2020.36.11 and now 2020.48.10.

If I drive, and then plug-in and start charging right away, it always work.
If I let the car cool down, don't know the exact threshold, and then plug-in and start charging OR use schedule charging, it will fail.

Once in failed loop, if I open a door, or start heating with the app, then it will start to charge correctly.

Christian

 

[PapaH67]

You are right about the battery temp. In my case, I was assuming the battery was near or between the inside and outside temps because it sits about 6 hours between the last time it was driven and when the charging attempts to start.

Last night I tried Scheduled charging off and the start/stop cycling occurred right away. I opened the door and waited for the radio to play and then plugged in and charging started. This showed me that it doesn't matter if you select Off, Scheduled, or Depart At - all settings will fail when the battery is not ready to take a charge. Getting the heater (probably or AC) going will go through the proper battery initialization sequence that is messed up in these software versions.

 

[MN-MS100D]

I am going to have Tesla look at my case, which sounds similar to others. Really bad top-off problem yesterday. See attached graph. It took over an hour for the charge to "take" and settle on a continuous charge. I would suspect many more Tesla owners have this happening, but they are unaware of it because the car eventually charges completely. I'm also sure it hampers any attempt at scheduled charging. Lastly, this exact charging problem occurred last winter (2019) but "resolved itself" through the winter.

 

[PapaH67]

I was just updated to Version 2020.48.12.1 last evening and it seems to corrected the charging problem! I set the charging back to Depart At 8:00 am and plugged the wall charger cable in at 9:15 pm. The car slept for the 8 hours from being plugged in until the start of charging time, so the batteries were cold soaked, just like my normal failure mode of the past. This morning, the car was fully charged and ready to go with no start/stop charging (according to the TeslaFi logs, attached below). Note the reduced initial charge rate on the graph that shows the results of the software changes.

This is one data point for me, but it has been since August 21st that it worked normally. Like I noted in a prior post, the first occurrence was August 22nd on Version 2020.32.2 and has failed almost every day since then, so this is a great result to see.

 

[MN-MS100D]

@PapaH67: I hope it solves the problem. I just checked my app, and I have a update 2020.48.12.1 waiting to install. I will report back next time it tops off the charge in the garage with the new update.

 

[ccharleb]

Got 2020.48.12.1 yesterday.
Did one test this morning and it charged perfectly! Let's monitor for a few days, but it's looking good!

I was having this issue since October.

 

[PapaH67]

Night #2 for me and it charged properly. However, I had it set to Scheduled Departure for 8:00 am and the cabin did not pre-heat for me even though it was still plugged in. I had to use the app to initiate the cabin warming. I don't know if this is new behavior with this release or if it had broken in the past - it's been warm enough here and with no commute to work these days, I rarely took the car out early in the morning.

 

[evfeh]

Wow, great to hear. I just updated to 2020.48.12.1 today and will report back. Will wait until car is cold in the garage and attempting to charge on it.

 

[evfeh]

Issue is fixed for me.

 

[ckoval7]

I just had this issue start this weekend, but I've been on 2020.40.9.2 since Nov 25th. I'll get woken up at 4 in the mornng to the sound of the contactors engaging and disenaging every 5 seconds. If I go out to the car and wake it up it charges fine. I put in for an appointment with Tesla for next week, but we'll see if they just push an update to my car. Reading this thread gives me hope the car isn't actually broken.

 

[random155]

Great for all the newer owners and their update. 2014 still waiting for the update to fix this.

 

[Zuikkis]

2013 here and 2020.48.12.1 and issue is fixed. But I have MCU2..

By the way, instrument cluster seems to be always powered now during charging. If I remember correctly, it was blank before unless you woke it up by opening the door? So perhaps they fixed the problem by not letting car sleep while charging?

 

[MN-MS100D]

Not fixed for me. 2017 MS100D. MCU2. HW3. 2020.48.12.1. Still bouncing from 2 amps to 17 amps at 237 volts. Appt made for next week for this issue and door handle problem.