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Significant loss in mileage

EvilEmre

Member
Mar 20, 2021
6
1
Victoria, Canada
Just curious if anyone has seen a massive loss in mileage lately? My Model Y (2020) was at 512km (318 miles) at 90% charge when I first got it in September. Now, it's down to 405km (252 miles) at 90%. The Tesla repair shop says that's completely within range of a normal battery. I call bullshit. I've lost over 100km of travel. Seems unacceptable to me. Anyone else have this issue? I feel like it happened after an update.
 
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jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,896
12,621
Riverside Co. CA
Just curious if anyone has seen a massive loss in mileage lately? My Model Y (2020) was at 512km (318 miles) at 90% charge when I first got it in September. Now, it's down to 405km (252 miles) at 90%. The Tesla repair shop says that's completely within range of a normal battery. I call bullshit. I've lost over 100km of travel. Seems unacceptable to me. Anyone else have this issue? I feel like it happened after an update.
The model 3 and model Y have the exact same battery, so everything related to this question for model 3 is relevant to model Y.

Here is a 35 page thread in model 3 section discussing the battery maintenance system and how it can get out of whack:



here is a 100+ page thread on this topic of "battery range, whats expected"


TL ; DR for the first thread = If you have a specific charging regimen that you developed because of reading here that you need to charge to 82.445622% but only if cloudy outside and on a thursday, maybe try just setting it to a couple different percentages and let it sit for a while.

TL ; DR for the second thread, yes this is normal, expected, etc, and you likely have not lost 100km of travel.
 

Watts_Up

Active Member
Mar 4, 2019
3,724
2,705
In a galaxy far, far away
Basically, a % value and a range give only an estimate of the battery condition based on previous usage and other factors such as temperature.
So if you only charge and discharge the battery by a small amount, the result will not be very precise.
Cells need to be balanced to get maximun capacity, this can be obtain by doing a full discharge and low speed recharge.
Also the battery capacity degradation has been reported been higher the first year.

A more precise evaluation would be to measure the energy produced,
such as the distance at constant speed from (close to) 100% until depletion (close to 0%).
And then to measure the energy needed to recharge the battery to the initial value.
Doing this, may be every 5,000 miles, could be a good way to monitor the battery capacity degradation.

What I could recommend is to use the ODB2 based Scan My Tesla App to get the original and current battery capacity values.
 
Last edited:

mark95476

Active Member
Jun 21, 2020
1,851
1,429
Bay Area CA
Yeah, I'm calling bullshit. 318 miles @ 100% SoC maybe, no way at 90% SoC.

Brand new user posting obvious FUD.

Just curious if anyone has seen a massive loss in mileage lately? My Model Y (2020) was at 512km (318 miles) at 90% charge when I first got it in September. Now, it's down to 405km (252 miles) at 90%. The Tesla repair shop says that's completely within range of a normal battery. I call bullshit. I've lost over 100km of travel. Seems unacceptable to me. Anyone else have this issue? I feel like it happened after an update.
 
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TesMY

Tesla enthusiast
Jun 9, 2021
136
135
Seattle
Just curious if anyone has seen a massive loss in mileage lately? My Model Y (2020) was at 512km (318 miles) at 90% charge when I first got it in September. Now, it's down to 405km (252 miles) at 90%. The Tesla repair shop says that's completely within range of a normal battery. I call bullshit. I've lost over 100km of travel. Seems unacceptable to me. Anyone else have this issue? I feel like it happened after an update.
Depends on your driving conditions the estimates will vary. Just like a gas car, if you had been driving in city a lot, it will show reduced miles, if you had been doing a lot of highway miles, you will get higher range.
 

roblab

Active Member
Jul 15, 2008
3,711
3,219
Angwin (Napa Valley) CA
Depends on your driving conditions the estimates will vary. Just like a gas car, if you had been driving in city a lot, it will show reduced miles, if you had been doing a lot of highway miles, you will get higher range.
Unless your highway miles are being done at 90 mph. And even your city miles can go up if you drive gently from the stop light, etc. The range numbers are calculated at speeds closer to 60.
 

mark95476

Active Member
Jun 21, 2020
1,851
1,429
Bay Area CA
Correct. No way this guy was getting 318 miles @ 90% SoC. That's obvious BS so this battery degradation complaint is FUD.

I don't think you're lying but I think something is off with your initial reading; either it just wasn't accurate or you misread because EPA estimated range is 326 miles at 100%. 90% should be around 293 mi.

As jjrandorin said, it likely has to do with your charging regimen and what the computer sees, not with your actual battery capacity. My Y is showing 263 mi at 90%, likely because we rarely let the battery charge get very low or very high.
 

iamnid

Member
Dec 4, 2019
736
744
Riverside, CA
I don't think OP is lying, I just don't think they understand how the estimate works. The numbers shown vary SIGNIFICANTLY based on how you've been charging etc. I haven't had my Model Y long enough to experience it yet but I've certainly seen the numbers vary by 20+ miles on our Model 3 SR+. A few long cycles (down to less than 10% and then back up to 90%) seems to fix it where it shows a number closer to the rated range. In my experience, this seems to happen when I go through periods of very little discharging before recharging.
 

maximus96

Member
Apr 19, 2020
526
351
Bay Area CA
divide 72500 by whatever your lifetime wh/mi is, that is your max range at 100%

to achieve 320 miles of range, you'll need to drive it at 226 wh/mi...which is doable if its all flat city streets
 

mark95476

Active Member
Jun 21, 2020
1,851
1,429
Bay Area CA
I try to take the fun way (up and down mountain roads) and regularly get <230 Wh/mi. I think my car is liking the warmer weather, even though I'm using AC. I'm sure I'd get even better efficiency if I was stuck in stop-and-go urban traffic.

MY_efficiency_jun22.png


divide 72500 by whatever your lifetime wh/mi is, that is your max range at 100%

to achieve 320 miles of range, you'll need to drive it at 226 wh/mi...which is doable if its all flat city streets
 

Darmie

Super Member
Supporting Member
Jan 13, 2016
2,087
1,388
Clear Lake TX.
Hate it or like it, if you are serious about monitoring battery usage, efficiencies and phantom drain, Teslafi has done a remarkable job keeping track of it all.
 

AKTech.it

Member
Jun 2, 2020
209
133
Texas
Need more info before we can make a proper diagnosis:

1) ambient temps/season when car was purchased
2) driving history wh/mi since car was purchased
3) current ambient temps/season and driving habits
4) when was the battery fully depleted and recharged to 100%?

I ask these because as a MYP owner with 37k miles, I was getting 310 miles on a 100% charge and about 280 on 90% - as of right now, it depends on my driving habits but I get anywhere from 255 at 90% to 265 right now after 37k miles.
 

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