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Model 3 LR battery charge level drop

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6.3K views 4 replies 4 participants last post by  joanb  
#1 ·
I received my 2022 Model 3 LR back in March 2022. It has a stated range of 358 miles. Since purchasing it I had never put a 100% charge on the battery. I set my charge limit to 80% as recommended. This produced a consistent 278 miles. Back in November of 2022 my wife and I took a longer trip, so I charged up at home to 95%, which yielded 338 miles on my charge indicator on the screen. That seemed to be about where it should be since 95% of 358 is 340. By that time I had reset my charge limit for my normal charges to 85% because that produced 302 miles of charge making it easier for me to mentally keep track of things. Then a couple of months ago I noticed after an 85% charge my car was only showing 278 miles again, not 302. At first I thought it must be due to the fact that I had been running the cabin heater occasionally during some cold snaps. After a couple of identical charges I intentionally avoided running the heat for a charge cycle to see if it would return to 302 miles, which it didn't, still 278 at 85% charge. Next, I checked my setting to see if somehow it had gotten reset back to 80% charge, which it had not, still set at 85%.

A couple of weeks ago I was planning a short trip, so for the first time I set my charge to 100%. The car showed 327 miles on the full charge. In the meantime I've been reading about how Tesla had reduced the charge capacity on some Model S and Model X cars back 2019 with an OTA update and explained it as a safety issue when they were questioned about the mileage reduction. A class action lawsuit ensued with Tesla losing and being required to pay the affected owners $625. I recently read a story saying a similar thing is happening again with some Model X and Model S cars. This got me wondering if an OTA update might be responsible my my mileage reduction? In my case, it certainly didn't follow a pattern one might see with normal battery degradation, which would be a slow drop over time. Mine occurred instantaneously, going from 302 on one 85% charge down to 277 or 278 on all subsequent 85% charges. I always charge at home with Level 1 or Level 2 charging. I've only had one five minute DC charge soon after purchase just to test if that function was working properly. So, my question is: Have any other 2022 Model 3 LR owners noticed anything similar with their charge limits?
 
#2 ·
This is most likely just the BMS (battery monitoring system) becoming uncalibrated. When this happens, it errs on the side of showing less range than what the car is capable of, so that you don't get surprised and run out of juice.

Run your battery below 50%, and leave it there for several hours. Then charge up to 90% and leave it there for several hours. That will help calibrate the BMS. See what it reports then.

In general, you're better off just setting your battery level display to percentage instead of miles.
 
#3 ·
Here's an example of recalibrating the BMS.
The BMS needs to see the behavior of the battery over a substantial portion (40% or more) of its range in order to be decently accurate.
Note that this is for a 2018 Model 3 Performance, which was rated for 310 miles when new.

After driving to Florida and back, I let my car sit overnight at low SOC (~25 miles).
I checked this morning, and the Tesla app says I will have 267 miles at 100% charge. That's the lowest I've ever seen.

I'm going to charge it up to 90%, let it sit overnight again, and see if that helps calibrate the BMS.
Update: after sitting overnight at 90% SOC, it now shows 293 miles at 100% charge. :cool:
 
#5 ·
I also noticed that sudden drop in range a few weeks ago. I will try the recalibration approach. Meanwhile, is there a way to display the kwh availability of the battery? I think that would be much more meaningful than a %battery, especially since a 100% battery may mean fewer miles if the battery capacity has degraded.