M3 Overcharging Slightly with 2021.4.18.3

[drtimhill]

Just noticed a slightly odd behavior after getting 2021.4.18.3. My car, which is set to charge to 70%, always seems to charge to 74-75% instead. Not sure if its *actually* charging to a higher level or the readout is wrong (i.e. its still "really" charging to 70% but its displaying it at 75%).

Double checked the settings in the Charging panel .. and it clearly shows the charge way above the set charge level both in the car and on the phone app.

 

[Sophias_dad]

When you get the notification on your phone that its finished charging, is it at that moment 70%? I've seen 90% drift up to 94% over a period of time without any actual charging going on, which surprised me.

 

[GtiMart]

Yep, I would also assume its bms adjustment after the charge, this has happened to me for the most part of my ownership, more than a year.

 

[drtimhill]

Both are possible, I'll watch for these things. However, in two years of owning the car I've never seen it do this before the update, and now its doing it every time.

 

[jjrandorin]

FWIW, it this happened to me after applying this update. I charge to 90% all the time, and have done so basically since I got the car 2.5 years ago. I know exactly how much 90% charge is, represented in miles, for my car.. After applying this update, and charging overnight from driving into the office one of the rare times I need to go in there atm, my car had 9 more miles than I was used to seeing.

I looked a little closer, and saw that my car had charged to (on the slider) around 93 ish percent. I went into the office again, and when I came back, simply moved the slider down some to around 80% ish.

TL ; DR ... yeah the behavior seems different on this version to me as well.

 

[minsup23]

I have had this issue for quite some time. It only happens if I am charging more than 15+%. Not sure why it keeps happening but I guess not a big deal

 

[ochompsky]

noticed this as well after the update

 

[outdoors]

FWIW, it this happened to me after applying this update. I charge to 90% all the time, and have done so basically since I got the car 2.5 years ago. I know exactly how much 90% charge is, represented in miles, for my car.. After applying this update, and charging overnight from driving into the office one of the rare times I need to go in there atm, my car had 9 more miles than I was used to seeing.

I looked a little closer, and saw that my car had charged to (on the slider) around 93 ish percent. I went into the office again, and when I came back, simply moved the slider down some to around 80% ish.

TL ; DR ... yeah the behavior seems different on this version to me as well.

Charged through 3% on both cars, on both last two charges. Both since updates. Haven't had this behaviour in few updates. Nothing to worry about as usual.

 

[KenC]

Is there a temperature change from when you charge, to when you check your car in the morning? Because I've seen temp changes, affect the SOC level.

 

[jjrandorin]

Is there a temperature change from when you charge, to when you check your car in the morning? Because I've seen temp changes, affect the SOC level.

In my case, not really.. my car is in my fully enclosed, drywalled garage with insulated garage doors, and I live in southern california. I also set my car to start charging at 3am in the morning, and the latest it ever finishes is about 6am, depending on where I have gone the previous day. The temp in my garage between 3am and 6am is pretty steady / constant.

 

[GtiMart]

Battery temperature augments during the charge, and will lower after the charge is complete...even in a garage.
Otherwise, it's not just temperature. The BMS will recalibrate once the car falls asleep. It's possible that this calibration figures out that you are charged a bit more than you chose.

 

[drtimhill]

Curiously, this seems to have fixed itself .. I've not touched the charging settings but now it does stop at 70% again. As others have speculated, this may have been some kind of BMS internal calibration going on, though traditionally that doesnt happen at such a low SoC (so far as anyone knows from the vague hints we have got from Tesla over the years).

I dont think it was temperature related .. this is on a home charger in a garage which, while not temp controlled, is pretty consistently between 55F and 70F.

 

[JCtx]

This happen more when supercharging, and as somebody else already mentioned, when charging more than 'x' percent. I've been supercharging often lately, since my garage gets super hot (110F lately here), and I don't want to get my adapter even hotter, and supercharging is free this year. I have it set up at 85, and at 85 charging shuts off, like it should. But after driving home like 3-1/2 miles, it arrives with 84, and the next morning it's like 87. When charging at home, it might be up 1% at the most. But it happens after the system shuts off charging at the designated percentage, so nothing wrong with anything.

 

[Rottenapplr]

Same here. It’s annoying but I don’t charge to 90% anyways so no harm.