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How is rated range calculate?

How is rated range calculated? I’m sure this has been answered somewhere else within the forum, but I cannot find the answer. So I apologize for the redundance.

I’ve called several SC’s and have received different answers than my local SC.

The reason for the question is my rated range on one of my Tesla’s is significantly higher than my other. This is despite my having 30,000 more miles and two years older and a smaller battery: Obviously concerning.

Tesla keeps telling me that the way my rated range is calculated is really the only difference, So I’m trying to find the exact calculation bc I feel like I’m being blown off by Tesla.

Thanks so much. This has become a major headache.
 

Rocky_H

Well-Known Member
Feb 19, 2015
8,607
11,182
Boise, ID
How is rated range calculated?
That, just like for any gas or electric car, is according to the EPA test procedures. That's why it uses the word "rated". That is from its EPA rating. Each car model and version gets a rating of total range and efficiency value.

The reason for the question is my rated range on one of my Tesla’s is significantly higher than my other.
Are they different model types? The same as with gas cars. If you have two different versions of a Honda Accord, for instance, and one has the 4 cyclinder, while the other has the 6 cylinder, they are going to have different gas mileage ratings. So the Model S 60kWh is going to have a different rated miles efficiency constant than a P100D. And of course the larger body of the Model X has more wind drag, so it has a different efficiency than a Model S or Model 3.
 
The displayed range is part calculation and part guess. Battery percent is compared to full and empty charge, which is compared to the way you've been driving the last so many miles. With time and thought, an experienced driver can guess better than the car does. And maybe change his driving and speed so he's right.

I'm not even sure there's a calculation. I think it varies if there is. All I have found is that it's pretty durned close to what you will get out of your battery.

Point of interest: Daughter arrived at house w/ 15 miles remaining. A few minutes later she went out to find that the expected range had dropped to one mile, "and I wasn't even moving!" She'd driven 6 miles up a thousand foot hill, and the car had recalculated.
 
Rated range is from the official EPA (for US) mileage rating. For my X the official consumption is 332 Wh/mile. The car has to estimate the number of kWh it can safely draw from the battery (battery voltage is one input to that calc) and then divides that kWh by the official consumption constant (times 1000 for kW to W) to get the number of rated miles available. The calculation has nothing to do with your driving, and is not an estimate of how far you can go (unless you exactly match your official consumption rate). It's just one way to describe the energy available in your battery (RM's times .332 kWh for me).

The navigation will give you a personalized estimate of RM's required to reach your destination, including elevation effects but excluding headwinds and who knows what else. EVTripPlanner, ABetterRoutePlanner, and the EVTO app will also estimate RM consumption for a given trip, and you can adjust the condition parameters to your liking.
 
Rated range is from the official EPA (for US) mileage rating. For my X the official consumption is 332 Wh/mile. The car has to estimate the number of kWh it can safely draw from the battery (battery voltage is one input to that calc) and then divides that kWh by the official consumption constant (times 1000 for kW to W) to get the number of rated miles available. The calculation has nothing to do with your driving, and is not an estimate of how far you can go (unless you exactly match your official consumption rate). It's just one way to describe the energy available in your battery (RM's times .332 kWh for me).

The navigation will give you a personalized estimate of RM's required to reach your destination, including elevation effects but excluding headwinds and who knows what else. EVTripPlanner, ABetterRoutePlanner, and the EVTO app will also estimate RM consumption for a given trip, and you can adjust the condition parameters to your liking.

Do you have something from Tesla on this? Your answer makes the most sense. ie, rated range is a reflection of the battery’s current capacity.
 

Big Earl

bnkwupt
Supporting Member
Jul 12, 2017
7,890
15,847
La Conner, WA
How is rated range calculated? I’m sure this has been answered somewhere else within the forum, but I cannot find the answer. So I apologize for the redundance.

I’ve called several SC’s and have received different answers than my local SC.

The reason for the question is my rated range on one of my Tesla’s is significantly higher than my other. This is despite my having 30,000 more miles and two years older and a smaller battery: Obviously concerning.

Tesla keeps telling me that the way my rated range is calculated is really the only difference, So I’m trying to find the exact calculation bc I feel like I’m being blown off by Tesla.

Thanks so much. This has become a major headache.

Is one of your Teslas a P85 and the other a 90 something? Rated range will deteriorate over time with battery degradation and 90 kWh packs suffer the worse (also some 75 kWh packs that are based on similar chemistry).
 
It will be just due to the usage of the P90DL being rated slightly higher than the P85+, but offset by the slightly larger battery in the 90.
Then minus slight degradation from each battery and that’s your difference.
I’m not following. If usage is part of the calculation, then why the big difference? Driving habits are identical. Only I drive the cars.

My p85+ has degraded 5 miles over 41k miles and 5 years. My p90dl has degraded 17 miles over 2.5 years and 14k miles. Either my p85+ is outperforming or my P90dl is a dudd; or, a combo of both.
 

Darmie

Super Member
Supporting Member
Jan 13, 2016
2,674
1,799
Clear Lake TX.
I understand that Rated range is displayed on the consumption screen. If your energy usage is above that line you are using more rated range than displayed and if your usage is below that line you will travel further than rated range. I have often calculated a 1.2 buffer + 20 if I'm traveling on highway between superchargers or between any charging. With 100 miles to travel I'll X 1.2. Then 120+ 20 =140.
 

ShockOnT

⚡️⚡️⚡️⚡️⚡️
Jun 26, 2016
3,446
3,233
Sydney
I’m not following. If usage is part of the calculation, then why the big difference? Driving habits are identical. Only I drive the cars.

My p85+ has degraded 5 miles over 41k miles and 5 years. My p90dl has degraded 17 miles over 2.5 years and 14k miles. Either my p85+ is outperforming or my P90dl is a dudd; or, a combo of both.
Not your usage. The rated usage of each of those two models.
This doesn't change over time, so the reduced rated range you're seeing is due to different rates of battery degradation in your two cars.
 
  • Informative
Reactions: Parker and Rocky_H

ShockOnT

⚡️⚡️⚡️⚡️⚡️
Jun 26, 2016
3,446
3,233
Sydney
I’m not following. If usage is part of the calculation, then why the big difference? Driving habits are identical. Only I drive the cars.

My p85+ has degraded 5 miles over 41k miles and 5 years. My p90dl has degraded 17 miles over 2.5 years and 14k miles. Either my p85+ is outperforming or my P90dl is a dudd; or, a combo of both.
Funny thing is, I always use percentage rather than rated or typical miles (or kms in my case).
So my car hasn't degraded at all. Still charges all the way to 100% :)
 
My p85+ has degraded 5 miles over 41k miles and 5 years. My p90dl has degraded 17 miles over 2.5 years and 14k miles. Either my p85+ is outperforming or my P90dl is a dudd; or, a combo of both.
That doesn't sound too surprising, as there are numerous reports from owners here in TMC that the 90kWh battery packs (especially the early ones) saw significantly more initial degradation than the older 85kWh packs--the cell chemistry is different in the 90kWh packs.

And, yes, the rated range is calculated based on the EPA rated efficiency of the specific car in question, as @animorph explained. For example, rated efficiency for my S70D is 290Wh/mile resulting in a rated range of 240 miles. My car is a bit odd, however, since it has never been able to charge above 236 rated miles at 100% (214rm was the 90% when new) and that has dropped to 234rm at 100% and 212rm at 90% due to degradation over 2.25 years and about 25k miles.
 
That is what I believe to be true, as well. ie, rated range is effectively displaying what your battery’s capacity is, and therefore, whether it has suffered degradation.

However, my local SC keeps telling me that rated range is influenced by recent driving usage. eg, spirited driving causes a lower estimated rated range. So either my local SC is lying to me, or ignorant, or we are all wrong.

Does anyone have any documentation that shows that Tesla is, in fact, using US8004243B2 as the method for calculating rated range? Sorry to belabor the point, but I need something to show to my local SC. Much appreciated!!!
 
My RM's shown at 90% are always the same, except slightly lower with age and a jump lower when they changed my Wh/mile constant in firmware. Previous driving style has no effect. That you can check for yourself.

Edit: I should add that the temperature here (in the garage) has never been low enough to affect battery capacity.
 
However, my local SC keeps telling me that rated range is influenced by recent driving usage. eg, spirited driving causes a lower estimated rated range. So either my local SC is lying to me, or ignorant, or we are all wrong.
I don't believe what the SC said. They either not well trained or think we (the users) know nothing and can be fooled easily.
As a matter of fact, spirited driving does cause error in SoC estimation but often over estimated. Take one of Bjorn's video for example:
Under heavy load, the car run out of juice even there was 14km left. I had very similar situation once when drove off the high way to a supercharger, the SoC displayed 3% and suddenly drop to 0 at arrival.

From what I've observed the internal data by Scan my Tesla, the change of "Full pack energy" is very gradual and always related to the "Full rated range". Someone said that you must complete a discharge-charge cycle to let the BMS modify the Full pack energy. That makes sense because the charging is relatively stable and well controlled.
 
That is what I believe to be true, as well. ie, rated range is effectively displaying what your battery’s capacity is, and therefore, whether it has suffered degradation.

However, my local SC keeps telling me that rated range is influenced by recent driving usage. eg, spirited driving causes a lower estimated rated range. So either my local SC is lying to me, or ignorant, or we are all wrong.

Does anyone have any documentation that shows that Tesla is, in fact, using US8004243B2 as the method for calculating rated range? Sorry to belabor the point, but I need something to show to my local SC. Much appreciated!!!

Rated range (also known as Total estimated driving distance TEDD per the manual) as the battery icon above the steering wheel is sorta displaying battery capacity. Remember that the car truly only knows when the pack is at 0% or 100% charge...anything in between is merely a guess by the BMS.

The BMS algorithm is in fact adjusting and calculating based on driving styles and watts used.
 

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