Battery degradation, real or imagined?

FogNoggin

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#1
I charge nightly at home, up to the line on the battery display that divides DAILY and TRIP. This line appears to be the 90% charge point but it's not specific. I have LR RWD, HW3 with software 2019.16.3.

My standard charge using this setting is just over 250 miles. Have you had the same result? Extrapolating this number means my 100% charge is only about 280 miles. I suppose I should actually charge to 100% to find out what it is.

Any insight would be welcome. Is there a standard charging procedure to "reset" the battery capacity readings? I'm concerned that my battery has degraded significantly but can't see how this could be possible with such a new car.
 
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MelindaV

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#2
I charge nightly at home up to the line on the battery display that divides DAILY and TRIP. This line appears to be the 90% charge point but it's not specific. I have LR RWD, HW3 with software 2019.16.3.

My standard charge with this setting is just over 250 miles. Have you found the same? Extrapolating this number means my 100% charge is only about 280 miles or 315, depending. I suppose I should charge to 100% to find out which is the case.

Any insight would be welcome. Is there a standard charging procedure to "reset" the battery capacity readings? I'm concerned that my battery has degraded significantly but can't see how this could be possible with such a new car.
did you check any of the suggested threads on this topic linked at the bottom of this thread? various things impact the what the car's computer calculates as the rated range. some possibly are FW related and change from one release to another. I had about a 10-15 mile drop with the 2019.12.1 FW that hasn't come back yet. last fall had something similar, but it returned to the previous normal after the next FW release.
drop-jpg.26601
 

FogNoggin

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shareef777

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I've been charging mine to 90% and have always had rated range showing from 278/279. Which would give me about 309/310 at 100%, which is what it should be. I've had this on every firmware version I've had.
 

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Hey that's cool! I had to run over and make my own. I couldn't get it to include all miles, but it's interesting to see the blips. I'm assuming (too lazy to go compare w/ update logs) the first blip is 2019.12 and the second is .16.

 

Frully

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OP here. Thanks for the link to that very informative thread. I feel much better knowing that it's just estimate upon estimate, BUT...

I just charged to 100%. It's far from 325 miles.
Have you drained the car below 10% lately? It's possible the car doesn't know its limitations and/or needs the cells balanced by taking them a long way down then back up. It seems odd that you would lose >10% in 2 months.

It's a really squishy estimate number how low 'empty' is since it's more like guessing an elastic band stretch based on force rather than measuring a tank whose level can be directly observed. If the car is always 90% at the end of the day and never taken low, the bms/energy management system might just not be calibrated.
 

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OP here. Thanks for the link to that very informative thread. I feel much better knowing that it's just estimate upon estimate, BUT...

I just charged to 100%. It's far from 325 miles.

View attachment 26611
One of the few ways to degrade your battery is to let it sit at near 100% or near 0%. So, if you haven't already done so, drive it so it's down to something reasonable.
 

FogNoggin

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#12
OP here. Thanks for the link to that very informative thread. I feel much better knowing that it's just estimate upon estimate, BUT...

I just charged to 100%. It's far from 325 miles.

View attachment 26611
Only twice have I charged to 100% and I've depleted it immediately afterwards. After doing a lot of research, I'm guessing that the range displayed is highly predictive. It's lower for me because the car is familiar with my driving habits which can burn electricity in bursts. My accelerator pedal frequently meets the floor as I often avail myself of advantageous acceleration.
 
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Frully

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#13
Only twice have I charged to 100% and I've depleted it immediately afterwards. After doing a lot of research, I'm guessing that the range displayed is highly predictive. It's lower for me because the car is familiar with my driving habits which can burn electricity in bursts. My accelerator pedal frequently meets the floor as I often avail myself of advantageous acceleration.
Again - have you recently had the battery LOW? If it doesn't know how low low is, then it doesn't have enough information to make a good prediction.
 

jsmay311

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After doing a lot of research, I'm guessing that the range displayed is highly predictive. It's lower for me because the car is familiar with my driving habits which can burn electricity in bursts. My accelerator pedal frequently meets the floor as I often avail myself of advantageous acceleration.
That's not how it works. The range displayed in a Tesla has nothing to do with past driving behavior.
 

FogNoggin

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#15
Again - have you recently had the battery LOW? If it doesn't know how low low is, then it doesn't have enough information to make a good prediction.
I've never had it lower than about 180 miles. I'm going to run it low this weekend. I'll report back what my new 100% charge level is. Thanks for your guidance.
 

SR22pilot

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#16
Again - have you recently had the battery LOW? If it doesn't know how low low is, then it doesn't have enough information to make a good prediction.
My battery changed form 310 to 295 a few weeks after I got my car. I have taken it down to 18 miles and back to 100% twice and in each case I got 295. I have never let the car sit at 100%. I usually charge to 90% since it was charging to 70% that seems to have caused the range drop. The car has been on a Supercharger only once. This is my AWD. My RWD calculates out to 325 all the time. That car has more miles than the AWD.
 

Dr. J

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#17
My battery changed form 310 to 295 a few weeks after I got my car. I have taken it down to 18 miles and back to 100% twice and in each case I got 295. I have never let the car sit at 100%. I usually charge to 90% since it was charging to 70% that seems to have caused the range drop. The car has been on a Supercharger only once. This is my AWD. My RWD calculates out to 325 all the time. That car has more miles than the AWD.
I don't know anything, but I do know that the AWD is less efficient than the RWD by about 5% to 9%. See https://teslike.com/range/ to compare, and see the back of the envelope calculations in this thread: https://teslamotorsclub.com/tmc/threads/lr-rwd-vs-lr-awd-efficiency-range.142388/ . By the EPA sticker, the AWD has 91% of the RWD's efficiency. Teslike @Troy's numbers are probably better for understanding the differences in range, which in the real world are (nearly) solely dependent on a constant cruising speed.

The car image in the app indicates that Tesla knows your car's configuration, including wheel size (though I wonder what the car displays for those who have switched wheel sizes). It could be that some firmware update corrected the car's overly optimistic range estimates for dual range and 19"/20" wheels. Which would look like battery degradation but in reality would be an attempt to adjust the driver's expectations, and the computer's calculation of, range.

Still, @FogNoggin's numbers seem out of whack, and should be checked by Tesla (unless they are corrected by the latest efforts).
 

SR22pilot

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#18
I don't know anything, but I do know that the AWD is less efficient than the RWD by about 5% to 9%. See https://teslike.com/range/ to compare, and see the back of the envelope calculations in this thread: https://teslamotorsclub.com/tmc/threads/lr-rwd-vs-lr-awd-efficiency-range.142388/ . By the EPA sticker, the AWD has 91% of the RWD's efficiency. Teslike @Troy's numbers are probably better for understanding the differences in range, which in the real world are (nearly) solely dependent on a constant cruising speed.

The car image in the app indicates that Tesla knows your car's configuration, including wheel size (though I wonder what the car displays for those who have switched wheel sizes). It could be that some firmware update corrected the car's overly optimistic range estimates for dual range and 19"/20" wheels. Which would look like battery degradation but in reality would be an attempt to adjust the driver's expectations, and the computer's calculation of, range.

Still, @FogNoggin's numbers seem out of whack, and should be checked by Tesla (unless they are corrected by the latest efforts).
I am not talking about the actual range but the rated range number. In a Tesla that isn't affected by how you drive. My car actually started at 308 and quickly went to 295 and has stayed there. The RWD started at 310 and stayed there till the update that changed the number to 325. Everything I have read has said the issue on the AWD is BMS calibration due to originally only charging to 70%. I have since charged to 90% and did two depletion/charge to 100% cycles with no luck resetting back to 310.
 

Dr. J

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#19
My car actually started at 308 and quickly went to 295 and has stayed there. The RWD started at 310 and stayed there till the update that changed the number to 325.
Yes, I understand what you're saying: you own one of each (RWD and AWD), they have both experienced changes to their rated miles, and you think the causes of those two changes are different. What I'm saying (and of course I could be wrong) is that the cause may be the same: Tesla updated the calculation of rated range in both cars to better match real world experience.
 

SR22pilot

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Yes, I understand what you're saying: you own one of each (RWD and AWD), they have both experienced changes to their rated miles, and you think the causes of those two changes are different. What I'm saying (and of course I could be wrong) is that the cause may be the same: Tesla updated the calculation of rated range in both cars to better match real world experience.
When I got the RWD, a full charge calculated out at 310. The RWD showed no change until the update that officially changed the RWD rating from 310 to 325. That change I fully understand. Remember that the RWD was originally rated at 310 and that was later changed to 325.

The AWD is still rated at 310. When I got mine (30 Sept) it calculated out to 308. After a few weeks, before I even got the RWD, it was at 295 and has stayed there. There is a Like Tesla video on this issue. According to Tesla, it comes from charging to only 70%. Tesla says charge to 90% to prevent it. Then they say to reset the BMS, discharge to under 15 % and charge to 100%. I have done that twice but it hasn't reset.