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MASTER THREAD: Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

CA_Car_Guy

Member
Nov 10, 2019
14
6
Bay Area California
I have a LR AWD built in 9/19, and have had seen my rated miles drop pretty steadily since getting the car, and am currently sitting around 295 miles of rated range at 100%, with 4000 miles on the odometer. To try and better understand things, I started tracking nominal full pack with Scan My Tesla at the beginning of December. I had 74 kWh at the beginning of December with 3000 miles on the odometer. Today, with 4000 miles on the odometer, I have 72.8 kWh. The decline in my rated miles at 100% and nominal full pack values correlate very strongly when graphed out vs. time or mileage, and it seems likely that the two are calculated in a similar manner. Extrapolating the trendline for the nominal full pack curve backwards to when the car was purchased gives a nominal full pack of 76 kWh.

I live in the San Francisco Bay Area, and the car the garaged at night, so my max temp swings are about 50 to 80 degrees at most, so temps really aren't much of a factor. I'm willing to see how things fare over time, but I'm pretty sure my battery is going to be one of those that makes everyone else's batteries look good. It seems like a lot of change for such a short period of time (4 months, 4000 miles).

I have seen nominal full pack values on you tube (mostly on OBDII harness installation videos) range from 68-77 for LR Model 3's
Mine battery seems to be following the same trend. Also a 9/19 build.
 

ran349

Member
Jun 28, 2016
442
288
SoCal
Someone told me once that there are two SOC API numbers. It seems that the car and the Tesla app are using a different SOC API number than 3rd party apps like Stats. This inevitably leads to confusion. My rated range is not 284 miles. It's between 308 and 312 miles, but because of this SOC API difference, I get these outliers on very cold days. Today, while the car says my Rated Range is 312 miles, Stats is showing 307 miles. And, if you look at the SOC number they are using, it's different by 1%, Stats shows 59% and the Tesla app is showing 58%. That's what usually is showing, a 1% mismatch. Today, the temps were better, about 32F. When it's colder, the mismatch can be higher, obviously yesterday it was mismatched by 5%.
There are two battery level variables read from the API. One is called "battery_level" and is used by the 3rd party apps, while the car and Tesla app use the one called "usable_battery_level". That is the reason for the discrepancy.
Someone who uses the Stats app should notify the app developer and have him correct that. I use the API app called Remote Tesla, and I have notified the developer about the issue, which he plans to correct in the next update.
Since my car doesn't see much temperature variation, the two values match most of the time, and when they are different, the difference is only 1%.
 
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bdrathburn

New Member
Aug 21, 2016
4
1
South Carolina
Throwing in another data point.

I got my LR Dual Motor back in Aug 2018, have about 13,500 miles now and I am getting 246 miles at 90% charge. Last full charge got me 275.

Only a handful of times charged to 100% before a trip, less than 20 supercharging sessions, and kept the daily charge limit set to 80% for the first year of ownership.

Tesla support claims there is nothing wrong with the battery back via a remote diagnostic, have a feeling that I'm going to be making use of the battery warranty sometime in the next few years if the mileage keeps dropping like it has though.
 

Msjulie

Active Member
Jun 26, 2016
2,439
1,748
Monterey Peninsula
Wow, that's a pretty brisk loss. Here I am at 13k miles and 13 months, and I have 300 rated miles which would be 73.5kWh with SMT.

Ok I hate you! :)

Anyone in the San Jose area with a SMT setup? Might be interesting to gather a bunch of cars and check them out for a large(r) sample set? It's not that hard to put the plug in the between the seats right?
 

TimothyHW3

Active Member
Jun 2, 2019
1,032
569
Germany
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AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,458
12,702
San Diego
I do want to get my own but it means getting some kind of Android device (at least right now) to use it all.

thanks

If all you want to know is your kWh you can just look at your rated miles at 100%. Extrapolate from 90% to minimize error. You’ll be within 0.5kWh of what SMT says. There is no ambiguity on the rated miles number once it drops below 310. At 310, you could have a variety of energies between 76kWh and nearly 78kWh it appears. For a Dual Motor (but not 2020), just multiply the rated miles by 245Wh/rmi.
 

ALSETJC

Member
Jun 24, 2018
288
263
Toronto
LR RWD with 18s winters on .range is sitting at 467km or 290 miles of range extrapolated from the Tesla app ( no snowflake but close to it). Cold weather seems to adjust the values down a bit for safety. I will have to wait for warmer weather to verify what the summer range is.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,458
12,702
San Diego
Cold weather seems to adjust the values down a bit for safet

It is not for safety - the battery just has less available energy when it is cold, and the gauge directly reflects that. With a warm battery, you can get an idea of your true range, even when it is cold outside. Not sure if you track this, but if you had your car last winter you might not have noticed as much change, because you probably had a little extra hidden capacity with a new vehicle (the gauge does not seem to show the first couple % of capacity loss). So the cold weather did not bring you as far below 325 as it is this year.
 

duanra

Active Member
Dec 14, 2018
1,302
742
Montreal
It is not for safety - the battery just has less available energy when it is cold, and the gauge directly reflects that. With a warm battery, you can get an idea of your true range, even when it is cold outside. Not sure if you track this, but if you had your car last winter you might not have noticed as much change, because you probably had a little extra hidden capacity with a new vehicle (the gauge does not seem to show the first couple % of capacity loss). So the cold weather did not bring you as far below 325 as it is this year.

Interesting point when you evaluate the battery capacity by charging the battery to the max. However if you evaluate by extrapolating from 90% for instance, would the cold temperature reduce the ration between percentage and mileage/kilometer ?
 

Wnuk

Member
Jul 9, 2017
347
1,075
PA
Data point: I bought a used 2018 that was manufactured 11/18 and the previous owner purchased in January of 2019 so the car is a year old. I’ve only had it 9 days.

80% shows 240 miles of range, 90% at 270 miles. So 100% will likely net 300 miles.
 

Tedslaract

Member
Oct 13, 2019
10
2
San jose
Throwing in another data point.

I got my LR Dual Motor back in Aug 2018, have about 13,500 miles now and I am getting 246 miles at 90% charge. Last full charge got me 275.

Only a handful of times charged to 100% before a trip, less than 20 supercharging sessions, and kept the daily charge limit set to 80% for the first year of ownership.

Tesla support claims there is nothing wrong with the battery back via a remote diagnostic, have a feeling that I'm going to be making use of the battery warranty sometime in the next few years if the mileage keeps dropping like it has though.

My LR WD Sept 2019 is heading in that direction as well. loosing 2% after 3 months. so potentially 8% by the end of first year? Tesla guaranteed no less than 70% after 8yrs/120mi. so about 217mi. hopefully the cost of battery swap goes down....
 

ranova

Member
Apr 16, 2018
408
370
NorCal
DP: May 2018 LR RWD with 18" aeros. TeslaFi reports 295mi for 100% charge. I never got the 325 mi rated range, max was 313mi. Hopefully all these DPs are attributed with colder climates.

upload_2020-1-13_12-49-54.png

upload_2020-1-13_12-50-22.png
 
Apr 19, 2019
18
2
Texas
Bought my Tesla Model 3 in July 2019. Max charge was 319. Current full charge as of today is 270 at 6000 miles. That’s 16% loss in half a year?

Outside of doing the work of getting true range via this thread, I’m not happy at all.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,458
12,702
San Diego
There are two battery level variables read from the API. One is called "battery_level" and is used by the 3rd party apps, while the car and Tesla app use the one called "usable_battery_level". That is the reason for the discrepancy.

However if you evaluate by extrapolating from 90% for instance, would the cold temperature reduce the ration between percentage and mileage/kilometer

See above. It does make things confusing but the car appears to keep track and actually quantify the loss of capacity due to cold. It does not appear to change the ratio (as long as you aren't using a 3rd-party app to report the values).

I have very little experience with this, but I think this is related to the issue of there being a "nominal remaining" and "ideal remaining" value for kWh. Probably one changes with temperature and the other doesn't.

Speculation: Based on other people's posts, it appears if you extrapolate using the Tesla app % and the Tesla's rated miles, you'll still end up at close to your actual max (warm) rated miles (see post from @KenC & @ran349 on prior page)

Those who have full access to the CAN bus data can probably provide the exact formulas for the cold calculation and the "ideal" calculation. The thing I'm having difficulty with here is understanding whether there is more than one "fullkWh" value kept track of (one cold, one warm). I have seen people claim that the "fullkWh" (or "NomFullPack") value read back from the CAN goes down with temperature (which would be expected I would think). But if that were the case, that speculation above would not hold - the rated range when extrapolating the Tesla app % and rated miles would not extrapolate to your normal 100% - they would extrapolate to the miles corresponding to the new "cold" value for NomFullPack. However, if the "idealFullPack" value (not sure this exists based on what I have seen) were used to calculate the Tesla app's SoC, then all the observations would still make sense.

But in any case, that's very likely too much rambling to follow, so it's probably best to thoroughly warm the pack and check then, just to eliminate it as a variable. It's not too hard to do unless the conditions are really extremely cold.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,458
12,702
San Diego
Max charge was 319. Current full charge as of today is 270 at 6000 miles

Was that 319 when the car was brand new or did you wait a while to do that 100% charge? Is the 270 an extrapolated or actual 100% charge? You're in Texas so presumably the battery is warm (but it can be chilly there, and it can be quite misleading to extrapolate with a cold battery, especially if you're using a third-party app)?

If you really are at 270 rated miles at 100% with a warm battery, that's more like 19% degradation for an LR RWD (and at a minimum 17%):

Initial kWH: ~78kWh.

270rmi * 234Wh/rmi = 63.2kWh

63.2/78 => 81%

As mentioned in many places in this thread, you can give a deep discharge a try and then recharge - you never know, it could help (though I think the chances are low, and I'd save it for a road trip to avoid having to fiddle with it).
 
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ran349

Member
Jun 28, 2016
442
288
SoCal
Speculation: Based on other people's posts, it appears if you extrapolate using the Tesla app % and the Tesla's rated miles, you'll still end up at close to your actual max (warm) rated miles (see post from @KenC & @ran349 on prior page)

But in any case, that's very likely too much rambling to follow, so it's probably best to thoroughly warm the pack and check then, just to eliminate it as a variable. It's not too hard to do unless the conditions are really extremely cold.
I don't have personal experience in cold climate effects, but I think your speculation is probably true in most cases. In other words, your battery can be very cold and still not affect the NomFullPack value significantly.
However, I think @TimothyHW3 has seen cases where in "extreme" cold the NomFullPack readings have dropped > 1kWh.
But there is only one FullPack value, which is the NomFullPack. There is no IdealFullPack value.
 
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TimothyHW3

Active Member
Jun 2, 2019
1,032
569
Germany
I don't have personal experience in cold climate effects, but I think your speculation is probably true in most cases. In other words, your battery can be very cold and still not affect the NomFullPack value significantly.
However, I think @TimothyHW3 has seen cases where in "extreme" cold the NomFullPack readings have dropped > 1kWh.
But there is only one FullPack value, which is the NomFullPack. There is no IdealFullPack value.
I have seen it go from 75.7-9 to about 74.5 or something on my Norway trip. And it is back to 75.0-75.3 with 5-10C I hope I can get it back above 75.5 with 20C outside temp.
 

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