Charging status remains on Charging Completed

[randhier]

Has anyone ever had the status "Charging Completed" when the battery was not charged to set set limit?

I recently filled up all the way at a free ChargePoint station (to 306mi) due to an upcoming long trip. When I got home connected my 110v Tesla mobile charger to keep the charge till the trip (it was at 300mi). When I plugged it in the console said the charge was completed.

I've done the following but it still says "Charging Completed" once plugged in.
* Reset the console and re-plugged the charger.
* Disabled scheduled charge
* Unplugged and opened the port via the console and connected again
* Moved the charge limit below and above the current charge a few times


Car:
Model 3 AWD
Software Version 2019.40.50.7

Note: first post, not sure this is the correct board

 

[randhier]

Welp, it started charging again. I had unplugged it for a day, when it was plugged in again the car started to charge. Not sure what the issue was.

 

[user212_nr]

It sometimes does not want to charge to the max, especially on the 120v. It could be that the battery gets cold too quickly, and the charge rate is so slow that it is just wasting energy trying to warm the battery and run the charging system. Just my guess.

It didn't happen to me that extreme, but it stopped charging around 96%.

 

[EfficientWatts]

I've noticed this recently when trying to set a charge limit > 90% after the car has previously been >90%. Feels like the car is trying to protect the battery. Still it should rather pop up a message than outright not charge as that could be annoying for some that do need that extra range. Wonder if this behavior is a bug.

 

[toolman335]

My car won't let me recharge it if I'm charged to 100% but lost a few miles of range due to time elapsing or preheating the car.
I'm glad it doesn't start charging again so I don't have to worry about my son playing with it. He likes to turn light switches off and on like a madman, so I'm sure he's love to plug and unplug the car all day too. I'm thankful that the car would ignore him

 

[Massive Attack]

Perhaps this is the right place for my question. Is it normal during the cold months for the car to not make it to the charge level set in the app?

Here is the scenario: I have my M3LR set to 90%, I am using the UMC on a NEMA 14-50 dedicated to the Tesla in my garage. I'm driving maybe 3-4 times a week. For the past 2 months, temperatures are averaging around 32F (45F-48F in garage). Each time I get into the car, the charge is 89% or 88%. Sometimes the screen says, "Charging Complete." Other times it is charging.

Oh, and this appears to happen when I pre-heat before leaving, or if I just "check in" on the car when I'm in the garage.

Now I'm not getting all upset over 1-2%, but I just wanted to know if this is typical to expect. I'm sure this has been asked and answered, but my queries did not provide me with the answer.

This behavior started in December 2020, before I got 2020.48.35 (sorry, didn't keep track of the exact software revision).

 

[Rocky_H]

Is it normal during the cold months for the car to not make it to the charge level set in the app?

Let me preface my answer first, because with the way you state your question isn't what is happening.
It did make it to the set level and then dropped a little bit. And yes, that's normal. Two potential reasons that could be and/or/both:

1. The charging process makes the battery a little warm. Then the battery cools down. Batteries show a little less available energy when cold than when they are warm, so when it cools down, the car's battery reading sees a little less energy than when it stopped at 90% and then displays 89%.

2. Or if it's a few hours after your charging stopped, the idle drain from the low power computer stuff may have used up some to make it lower toward 89% instead of 90%, and combined with some cooling mentioned above.

The car doesn't constantly give little micro-pulses of energy to keep it exactly at 90% all the time. They don't want the charging cable energized and battery connected all the time. So it will let it drift down by a little bit before it decides to refill.

 

[user212_nr]

Perhaps this is the right place for my question. Is it normal during the cold months for the car to not make it to the charge level set in the app?

Here is the scenario: I have my M3LR set to 90%, I am using the UMC on a NEMA 14-50 dedicated to the Tesla in my garage. I'm driving maybe 3-4 times a week. For the past 2 months, temperatures are averaging around 32F (45F-48F in garage). Each time I get into the car, the charge is 89% or 88%. Sometimes the screen says, "Charging Complete." Other times it is charging.

The issue that the OP had on this thread was that they had a 120v power source. Since you have a 14-50 outlet, your problem should be not directly related.

It probably is normal though, the 1-2 percent lower in winter. The battery needs to be warm in order to charge, so it would be a waste of energy to warm it up just to recover 2%.

Also, when it is cold, the battery has less efficiency, so Tesla will adjust the % that it shows on the screen to a lower number than it is in reality.

 

[Massive Attack]

Thank you Rocky_H and user212_nr, I can live with those explanations.

 

[DaveRZ]

Also remember that your home charger, while perfectly adequate for overnight charging, can't fully keep up with the power draw that the car can use while preheating (granted only for a short time).

UMC2 Max - 7680 watts

Cabin heater on full ~7000 watts
Battery heater on full ~7000 watts
Computers ~250 watts
Plus whatever the blower fan, A/C compressor draw, seat heaters draw

So it would be quite normal to come out after 20 minutes of preheating and see a percent or two lost. I'm not saying that the car always runs these things on full blast, but that it can if it needs to.

 

[JCtx]

If the battery needs to heat up to charge to 100%, a 5-15 outlet is not going to cut it, since the battery heater will eat that up, and then some more. In mild temperatures, a 5-15 might be enough. In cold weather, you really need a 240V outlet.

 

[Rocky_H]

If the battery needs to heat up to charge to 100%, a 5-15 outlet is not going to cut it, since the battery heater will eat that up, and then some more. In mild temperatures, a 5-15 might be enough. In cold weather, you really need a 240V outlet.

People do have very different ideas of what "cold" means. If it's down into the 30's or about at or above the freezing point, it will still work fine. It would need to do some heating first, but once the charging gets going, that will sustain enough heat from the charging process to turn off the battery heating and continue. But if you're talking down to like single digits Fahrenheit, yeah, that probably won't be able to keep up.