Battery no longer charging to 100%

[Relentless]

Anyone having a problem with their battery no longer charging to 100%? I have a 2018 MX 100D with 20k miles now on it. Used to charge to 294 miles now indicates charging complete at 267 (91%). Happens when home charging and Supercharging. I normally charge to 70-80% and only occasionally charge to 100% for trips. Searched the forums and can't seem to find anyone reporting a similar problem.

 

[DCGOO]

Have you ever taken it down to 5% or less? If no, you might give it a try. Followed by a trip up to 100 again. Take the fuel gauge estimates with a grain of salt, especially in the winter. But 267 down from 294 in less than a year seems a little excessive to me. It may all come back next summer though. Winter is a really depressing time for an EV owner

 

[Relentless]

Ya, the cold weather definitely impacts performance but this is actually my 2nd MX (had one in 2017 too but it met up head-on with a tree after someone pulled out in front of me) and the battery never lost it's ability to charge to 100% even when very cold... I've had this one down to about 10%, never daring enough to bring it to 5. It's going to the SC soon for some attention so I plan on having them check it out then.

 

[Rocky_H]

Anyone having a problem with their battery no longer charging to 100%? I have a 2018 MX 100D with 20k miles now on it. Used to charge to 294 miles now indicates charging complete at 267 (91%). Happens when home charging and Supercharging. I normally charge to 70-80% and only occasionally charge to 100% for trips. Searched the forums and can't seem to find anyone reporting a similar problem.

You are being really confusing in how you are describing your symptoms. The title of the post says, "no longer charging to 100%", and in your post, you state how it's only getting to 91%. Do you know of the display setting, where you get to choose "Energy" or "Distance" for the units? If you have it set for "Energy", it will show all those units in % instead of rated miles. So are you saying that with the charge level slider moved all the way up, it actually displays only 91% on your battery meter? That is what your thread title confusingly indicates, and that really would be a problem, but I don't think that is going on.

However, are you just talking about how the "full" level in rated miles is just fewer rated miles than it used to be? If so, then that is a commonly known behavior from some inaccuracy of the battery measurement algorithms. The car will still think that is 100% and would display that if you switched to "Energy" units, but it's "seeing" a lower amount of energy than it used to and converting to a lower amount of the rated miles units.

 

[tes-s]

When it gets to 91%, does it say charging complete?
When you tell it to start charging again, does it resume charging?
When it was approaching 91%, or after you tell it to start charging again, how many kW charging does it show?

 

[Rocky_H]

When it gets to 91%, does it say charging complete?
When you tell it to start charging again, does it resume charging?
When it was approaching 91%, or after you tell it to start charging again, how many kW charging does it show?

That's why I wrote up the scenarios the way I did. You are off on a rabbit trail that isn't what's happening, but is how he worded it. I'm really sure it's not stopping at 91%. He said it's stopping at 267 rated miles, and then he's noticing that 267 versus the brand new number of 294 rated miles shows that it's only at 90.8% of what it displayed when new. That's a different issue than charge not completing.

 

[Relentless]

When it gets to 91%, does it say charging complete?
When you tell it to start charging again, does it resume charging?
When it was approaching 91%, or after you tell it to start charging again, how many kW charging does it show?

Yes, at 91% it says charging complete even though the charge level is set to 100%. I've tried to force it to start to charge by dropping the charge level below the current SOC and then bringing the charge level back up to 100%, it says starting to charge and then after a minute or 2 says charging complete with the charge level still being at 91%. The kw tapers down as it normally would at the end of a full charge... as if it had reached a full charge.

 

[Relentless]

That's why I wrote up the scenarios the way I did. You are off on a rabbit trail that isn't what's happening, but is how he worded it. I'm really sure it's not stopping at 91%. He said it's stopping at 267 rated miles, and then he's noticing that 267 versus the brand new number of 294 rated miles shows that it's only at 90.8% of what it displayed when new. That's a different issue than charge not completing.

It stops charging at 91% even though the charge level is set to 100%. It's actually progressively getting worse... it was stopping at 95% before even though it was set to charge to 100%.

 

[Big Earl]

Time for an appointment with the service center. It should always be able to charge to 100%.

 

[Relentless]

Time for an appointment with the service center. It should always be able to charge to 100%.

Certainly looks that way...to the SC I go... thanks all for the feedback!

 

[animorph]

A couple of threads have noted problems with low battery readings like this. Charging to 70%-80% has been associated with each one that I've seen. A reset at the SvC was required to fix immediately. Charging to 90% regularly may help/prevent the problem.

 

[Rocky_H]

Oh, OK. My assumption was off. Sorry, @Relentless for my assumption that this was yet another of the hundreds of posts of people misunderstanding their rated miles being lower.

 

[Relentless]

Oh, OK. My assumption was off. Sorry, @Relentless for my assumption that this was yet another of the hundreds of posts of people misunderstanding their rated miles being lower.

Lol, no prob... I agree it's something that's commonly misunderstood. I'm sure the SC will take care of it... have to bring it in for the much discussed noisy half shaft issue anyway... hoping the rumored improved versions really exist but I'm wandering off topic now...

 

[sjokomelk]

I have the same issue, but my car stops at 86%.
The service center told me to drive the car down to below 20% and let it sit over night, and then charge to above 90% and let it sit over night again for the BMS to reset/relearn. And do this a couple of times. Only issue is that the first time it stopped at 83% and second time 86% again.
I have sent an e-mail to my service center asking them for more help now since I'm going on a longer journey over X-mas, and I really need to be able to charge to 95% and run the car down to about 7-8% on of the legs.

 

[Relentless]

I have the same issue, but my car stops at 86%.
The service center told me to drive the car down to below 20% and let it sit over night, and then charge to above 90% and let it sit over night again for the BMS to reset/relearn. And do this a couple of times. Only issue is that the first time it stopped at 83% and second time 86% again.
I have sent an e-mail to my service center asking them for more help now since I'm going on a longer journey over X-mas, and I really need to be able to charge to 95% and run the car down to about 7-8% on of the legs.

Interesting, I've definitely run it below 20% and charged it afterwards to full charge (as full as it would charge) but I haven't tried letting it sit overnight after discharging. It sounds like it didn't solve the problem for you and I'm inclined to think it wouldn't as my experience with 'let it sit overnight and fix itself' has never worked... It usually ends up being an issue the SC has to correct. @animorph mentioned he's seen the problem noted by others and a reset at the SC corrected the issue. It's scheduled to go in next month for some attention - stay tuned - I'll update on the results after...

 

[tpham07]

This happened to like tesla's model 3 as well. they charged to 70% everyday and eventually the car thought 260 miles was a 100% charge.
the software gets confused.

 

[sjokomelk]

My issue got solved over X-mas.
A senior technician at my local service center told me I needed not only to have a high state of charge, but the car had to go to sleep for the BMS to calibrate. And apparently TeslaFi didn't stop polling the car, so it never got enough "rest" to figure things out. Removed TeslaFi from my car and quit the Tesla app on my phone. And then I set the car to charge to 82% (very close to what it stopped at earlier), plugged the car in to charge overnight and the next morning the car said 99% when I got in.

 

[Relentless]

Interesting... thanks for the info. I use Teslafi too. You mentioned you set it to charge to about where it would stop at before (82%) and then let it charge overnight then the next day it showed 99% after charging. So if I understand it correctly it showed a 99% charge even though you didn't have it set to charge to 100%?

 

[sjokomelk]

Interesting... thanks for the info. I use Teslafi too. You mentioned you set it to charge to about where it would stop at before (82%) and then let it charge overnight then the next day it showed 99% after charging. So if I understand it correctly it showed a 99% charge even though you didn't have it set to charge to 100%?

Correct!
I set it to stop at 82%, but it found out during the night that the battery actually was at 99%.
When I looked at my charging screen, the limit was still at 82%.

 

[Relentless]

Correct!
I set it to stop at 82%, but it found out during the night that the battery actually was at 99%.
When I looked at my charging screen, the limit was still at 82%.

Just tried turning off TeslaFi logging a couple of hours ago, left the charge limit set to 100% and left it plugged in and charging... it just finished charging and it now shows 99% charge! Highest I could get it before was about 85% (it was getting worse). Problem solved! Looks like it was the fact that TeslaFi was keeping it awake... guess we all need rest at some point lol. I didn't have TeslaFi setup to let it sleep, I'm now playing around with the sleep settings in TeslaFi so it can sleep but still have it connected to TeslaFi for logging when awake. Thanks for the great info!