Model Y never reaches its charging limit

[Hubbycat]

I have 2023 model Y LR and Tesla wall charger. In The Tesla app I have set charging limit to 80% but the car stops charging at 79%. If I want to have 80% I need to set the charge limit to 81%. It only started happening recently in the past I was able to get full 80%.
Has nobody seen this issue?

Tom

 

[Big Earl]

Some variability is normal.

 

[GtiMart]

Have you verified that it really stops and indicates 79% at the moment it stops? Very often it will indicate say 80% when it stops, but the percentage will have changed when you look at it the next morning. Various reasons, including but not limited to some energy expense, temperature changes, bms readjustment... All normal.

 

[nicholb]

Yes, I've noticed that. I have the app send charging complete notices. It use to always say complete 80%, but has said complete 79% the last few days.

 

[Watts_Up]

I notice there is always 1% difference between the car display screen and the value on my phone App.

May be you could use Scan My Tesla phone App to get more detail information, like cells voltage and temperature, and even degradation.

 

[nate704]

normal. just enjoy it. don't look at the numbers.

 

[E90alex]

It’s due to colder weather.

 

[Tam]

I have 2023 model Y LR and Tesla wall charger. In The Tesla app I have set charging limit to 80% but the car stops charging at 79%. If I want to have 80% I need to set the charge limit to 81%. It only started happening recently in the past I was able to get full 80%.
Has nobody seen this issue?

Tom

It's up to the BMS Battery Management System.

It might think the display number has drifted down, so the old 79% is actually the new 80%. It would stop at 79% and will update that 79% as 80% subsequently.

 

[Watts_Up]

I always put a little more, like 85%, because the time I seat in the car and just drive,
the value stays just above 80% for a little bit. and I feel better.

Otherwise if I charge at 80% it would be immediatly below the 80% value
and feel that I will have to charge it again soon.

 

[Hubbycat]

Have you verified that it really stops and indicates 79% at the moment it stops? Very often it will indicate say 80% when it stops, but the percentage will have changed when you look at it the next morning. Various reasons, including but not limited to some energy expense, temperature changes, bms readjustment... All normal.

Well, the internal screen shows only 79% even though it also shows charging limit to be 80% as the app on my iPhone. The car is plugged all the time so I would expect it to top up the charge if it drops below 80%. From what I've seen it simply stops at 79%. If I set charge limit to 81% it immediately starts charging and stops at 80%. Initially I thought it was something wrong with the app but I get the same result if I use internal screen.
From the replies I see it's a common problem.
Tom

 

[Hubbycat]

Yes, I've noticed that. I have the app send charging complete notices. It use to always say complete 80%, but has said complete 79% the last few days.

I'm glad to se that I'm not the only sone who has this issue. As you I have noticed that this started happening recently so I suspect it may be a bug in BMS introduced in the latest updates.

Tom

 

[Hubbycat]

It’s due to colder weather.

I doubt, it's not cold here yet and the car is in the garage all the time.

Tom

 

[brkaus]

Have you tried parking on a slight slope or bouncing the car by hopping on the bumper? It might help the electrons burp and allow it to fill to the top.

(Sorry, couldn’t resist)

 

[E90alex]

I doubt, it's not cold here yet and the car is in the garage all the time.

Tom

What’s the temperature there overnight? It doesn’t take much. Batteries like to be at like 75°F.

Mine does the same when it gets around low 50s ambient and you’ll notice up to 3% lower as it gets even colder.

Open the app and temporarily drag the charge limit up or down so you see the end of the line graph. You may see a little sliver of blue at the end of the green line indicating the battery capacity that’s not accessible due to cold temperature. When it’s really really cold you will see a snowflake icon next to the battery and that’s when it’s so cold you start getting limited power and regen.

 

[nicholb]

I'm glad to se that I'm not the only sone who has this issue. As you I have noticed that this started happening recently so I suspect it may be a bug in BMS introduced in the latest updates.

Tom

It may not even be the car, could also be the app reporting it down 1%. I have not checked as the charging usually finishes around 1am. The timing may correspond to installing 2023.27.7 on the car.

Anyway, not worried about it.

 

[Tonedog77]

normal, sometime it can vary by 3-5 percent. its the battery settling and adjusting its computing to calc the %

 

[jkdman123]

Had the opposite problem in my '19 M3. It used to go high by 4%+ routinely. I had to set it at 76% max to keep it from going over 81% sometimes. Don't recall that it went under the limit much. Usually the error was over whatever I set.

The MY seems to get closer to the limit I set.

 

[R.C.]

I've been seeing the same thing, set for 80, goes to 79. It was going to 81 until recently. I suspect the app because .. other odd things happening; amperage slide-bar keeps going to 48a even tho my limit is 24a (30a breaker). Also, how many kw added last charging session is no longer showing anything. All this on same "page" of app.

 

[Tonedog77]

I've been seeing the same thing, set for 80, goes to 79. It was going to 81 until recently. I suspect the app because .. other odd things happening; amperage slide-bar keeps going to 48a even tho my limit is 24a (30a breaker). Also, how many kw added last charging session is no longer showing anything. All this on same "page" of app.

its not the app lol. its the battery and chemistry of how batteries work. The car can only "gestimate" the true percentage of the state of charge. As it charges and charging stops after it has sat there its "settles" and can sometimes go up sometime go down sometimes of which by 4-5%. it happens over time if you dont let the battery drain all the way down sit at a low state and then charge to 100 and leave it to top balance. Its called calibrating the battery

 

[brkaus]

I've been seeing the same thing, set for 80, goes to 79. It was going to 81 until recently. I suspect the app because .. other odd things happening; amperage slide-bar keeps going to 48a even tho my limit is 24a (30a breaker). Also, how many kw added last charging session is no longer showing anything. All this on same "page" of app.

The slide bar should go to 48a when not plugged in and drop to 24 once plugged in.

What device are you using to plug in the car?