Range Estimates for Dummies

[Dr_G]

Looking for a used Tesla and would like to assess the battery. I believe this post is independen of model type.

Here are the sources I could find to determine current range:
1. As a baseline, the range when new is published somewhere. Is there a good, consistent source for all years and models?
2. Current range is shown on the range icon. If SOC is not 100%, would like to confirm that the range can be estimated by dividing by the SOC.
3. The energy app. Average the 5,15, and 30 mile ranges? They seem to vary more than expected.
4. The trip results. The trip "cards" show Wh/Mile for various trips, but you would need the current capacity in Wh to calculate range. Where would the current battery capacity be displayed? One of the stickies suggests using the energy app (Wh/mile X estimated range).

Is this really as complicated as it looks? Am I missing something?

Any comments appreciated! Thanks.

 

[beatle]

Estimating how far you can go with no respect to where or when you're going is almost useless as there are many variables that can affect efficiency.

The in car navigation is pretty good at taking these into account, however. For advance planning or to see if a particular year/trim will work for your use case, try using abetterrouteplanner.com and map out your trips with different vehicle configurations and different ambient temperatures, wind, rain, etc. It will also map out charging stops so you can see how long you'll be charging if the trip is long enough to warrant charging on the way.

As for estimating the battery health, yes you can just divide by the percentage to get a 100% estimate. It's not always perfect, but it's a pretty decent guess.

 

[cmaster]

When I first got my Tesla Model S, I always charge it whenever I get a chance. Even when it's 75% or 82% SoC. I was paranoid not to get my SoC to less than 50%.

That was 2017. As I travel more with the car, I don't care much as long as I can get to my destination with atleast 20% charge that is also located near a supercharger.

 

[Dr_G]

More interested in assessing an unknown car, rather that monitoring one's own. Please re-read OP. Thx

 

[GtiMart]

You can estimate the 100% SOC range from a lower soc. It gives an estimate but as you can see in some threads around here, the BMS can become slightly uncalibrated. In some cases you can help it and the number will change. Still, it gives an idea of the ballpark. You can see how mine evolved over time here.

There are differences of over 20kilometers (512km when new) probably because I charged to 100% that time and also let the car sleep at around 15% after a road trip. Depending on when you looked at my car you could have though it's better than, or lower than average. Don't put too much emphasis on this. You can use this to weed out really bad cases but that's it.

 

[Supcom]

Looking for a used Tesla and would like to assess the battery. I believe this post is independen of model type.

Here are the sources I could find to determine current range:
1. As a baseline, the range when new is published somewhere. Is there a good, consistent source for all years and models?
2. Current range is shown on the range icon. If SOC is not 100%, would like to confirm that the range can be estimated by dividing by the SOC.
3. The energy app. Average the 5,15, and 30 mile ranges? They seem to vary more than expected.
4. The trip results. The trip "cards" show Wh/Mile for various trips, but you would need the current capacity in Wh to calculate range. Where would the current battery capacity be displayed? One of the stickies suggests using the energy app (Wh/mile X estimated range).

Is this really as complicated as it looks? Am I missing something?

Any comments appreciated! Thanks.

The service mode in the car can run a battery health test. This test runs by depleting the battery fully, then charging it to 100%. The results can be viewed in the service menu if it's ever been run along with how long it has been since the test was run. The results will give you a percentage of the battery's new capacity.

The test does take a number of hours to run though, so it's not something that you can just do when you are lookiing at a car. But, it would be fair to ask the owner to run the test if you were serious about buying the car.

 

[Dr_G]

The service mode in the car can run a battery health test. This test runs by depleting the battery fully, then charging it to 100%. The results can be viewed in the service menu if it's ever been run along with how long it has been since the test was run. The results will give you a percentage of the battery's new capacity.

The test does take a number of hours to run though, so it's not something that you can just do when you are lookiing at a car. But, it would be fair to ask the owner to run the test if you were serious about buying the car.

Good thought. Thanks

 

[Dr_G]

You can estimate the 100% SOC range from a lower soc. It gives an estimate but as you can see in some threads around here, the BMS can become slightly uncalibrated. In some cases you can help it and the number will change. Still, it gives an idea of the ballpark. You can see how mine evolved over time here.
View attachment 1016502
There are differences of over 20kilometers (512km when new) probably because I charged to 100% that time and also let the car sleep at around 15% after a road trip. Depending on when you looked at my car you could have though it's better than, or lower than average. Don't put too much emphasis on this. You can use this to weed out really bad cases but that's it.

Great collection of data! What's your guess as to the error range if you just divide the range by the % shown by the range icon?