Model 3 Performance - charged to 100% shows 293 miles range. Why?

[Rhytid]

So @LakeForestM3, wanted to circle back on this, knowing this new information. The above is incorrect. I did not know that the underlying constants had changed (such events are very rare, and the addition of wheel options changing the constants is a new thing - though very understandable).

Previously: 310rmi*245Wh/rmi = 76kWh

Now: 293rmi*265Wh/rmi = ~77.6kWh

This means that nominally, you now have MORE energy available than you had before (assuming each “kWh” has the same energy content...which is very hard to determine). So this 293 rated mile drop is actually an INCREASE in range for you!

As far as I know this only applies to 2020 Model 3s - have not seen anything like this on my 2018.

And by the way, if you have a 2020 3P+, it is actually rated for 299 miles, not 310. You can see this on the window sticker. I think you may see a bump up to 299 in the coming weeks, but that is just a guess - I don’t know.

I will update my Lines and constants tracking post at some point soon.

Knowing what these constants are is key to understanding what that battery gauge shows - the number by itself is not extremely useful except as a relative measure - and not even that if the constants change. And they can always be derived as above from a picture of the Energy Consumption screen:

Charge Const = Recent Efficiency * Projected Range / Battery Gauge Displayed Miles

All numbers should have three digits for accuracy so should be done at a relatively high state of charge. (Greater than 70% or so.)

Alan,

Your analysis is great. I am getting a much better understanding of the battery situation in my car.

I have a 2020 MP3+ delivered on 12/10/19 and my range dropped after the 40.50 update. I originally had 279 miles at 90% charge and it dropped to 265 miles after the software update.

After reading your posts, I have a question......I am on 40.50.5 and when I slide the charge bar all the way to 100% on the app, it shows 298 miles (right after I drove a while and battery was warm).

So using your calculation, 265 Wh/mile x 298 miles = 78, 970 Watts.

Are we to think that the Model 3 battery is actually a 79 kW battery? Or possibly even a 80 kW if it has any built in buffer?

 

[AlanSubie4Life]

265 Wh/mile x 298 miles = 78, 970 Watts.

78970 watt-hours

Caveat that the slider is just an estimate - you may find your battery does not make it to that level. But it is an interesting observation from you nonetheless with a warm battery. I would recommend you report the 90% value and directly extrapolate (you can have an error of up to 3 miles (+/- 1.5 or so).

I originally had 279 miles at 90% charge and it dropped to 265 miles after the software update.

Is this with 2019.40.50.5, or was this 265@90% with 2019.40.50.1? I ask because I wonder if the constants changed AGAIN in 2019.40.50.5. We would need that Energy Consumption screen picture to know for sure.

Also, I ask because 265 projects to between 296 ([email protected]%) and 293 ([email protected]%) at 100%. Not 298.

I would guess your true 100% is likely closer to 294 or so. Hard to know without charging to 100%, which I do not recommend unless going on a trip.

Are we to think that the Model 3 battery is actually a 79 kW battery?

The EPA test in 2018 discharged 79.2kWh (true calibrated kWh) from a Dual Motor vehicle. So yes it has that capacity. It is required that the manufacturer make all of that capacity available for use. However, it is important to realize that in this test they drive until the vehicle stops moving - so they completely exhaust the buffer, which entails driving on the dyno for at least 10 miles after hitting 0 rated miles (the buffer energy is not shown as rated miles - the vehicle goes to negative SoC (as SoC is defined) when going below 0 rated miles). In other words, to access the energy measured when doing the EPA testing, you have to drive until your vehicle stops moving - which is not recommended.

 

[Rhytid]

78970 watt-hours


Is this with 2019.40.50.5, or was this 265@90% with 2019.40.50.1? I ask because I wonder if the constants changed AGAIN in 2019.40.50.5. We would need that Energy Consumption screen picture to know for sure.

.

My 90% dropped from 279 to 265 with the 40.50.1 update.

With the 40.50.5 update, my 90% seems to be 265 when battery cools down but when it is warm, it is at 268. I know you said the slider bar is not accurate but using that for both warm and cool battery conditions, I get two different numbers.

Warm battery: 268 at 90% and 298 at 100% (slider all the way up).

Cool battery: 265 at 90% and 295 at 100%.

I don't think I saw any changes with battery temperature with the 40.50.1 update (I was checking somewhat obsessively as it was a surprise to see such a big drop overnight).

So I am not sure if the constants changed but maybe the BMS takes ambient temperature into account better with the 40.50.5?

Car is sitting in a garage right now... probably around 50 degrees. I wonder how these numbers will change depending on ambient temperature changes.

 

[AlanSubie4Life]

So I am not sure if the constants changed but maybe the BMS takes ambient temperature into account better with the 40.50.5?

You can always tell whether the constant has changed by taking a picture of the Energy Consumption screen including those three numbers with three digits required on each (see above). This constant is not dependent on temperature (though battery energy content certainly is). We know it was 265Wh/rmi with 2019.40.50.1 with 20” wheels on a 2020 vehicle.

 

[rtshefe]

It definitely seems like we have gotten to the bottom of this...turns out tesla just updated the charge constants to more accurately reflect the real world results with the different wheel options.
This evening on a trip downtown and back I managed to get a bit under the rated wh/mi..the new numbers are definitely more realistic (at least with my p+ 2020) and seem much more accurate. At least now the rated range is achievable (when its not cold out)

Another thing I noticed after the update, my charging rate (mi/hr) at 32amp reduced to 27..used to be 29-30. I wonder if this is also due to the new constant.

 

[AlanSubie4Life]

32amp reduced to 27..used to be 29-30. I wonder if this is also due to the new constant.

Yes, that would follow. The charge rate will be reduced by the ratio 245/265 for a given input power, since each rated mile you add now contains more energy, as they have been redefined.

For a given source (below 32A), the SR+ already has a much higher charge rate (as measured in miles/hr) than the Performance/AWD, for example, for the same reason. Of course it only has a 32A charger rather than a 48A one.

Continuing that example, for input powers less than 7.7kW, the charging power will be the same, but the mile per hour rate will be different. You’re adding energy at the same rate, but the meaning is different.

This evening on a trip downtown and back I managed to get a bit under the rated wh/mi..the new numbers are definitely more realistic (at least with my p+ 2020) and seem much more accurate. At least now the rated range is achievable (when its not cold out)

Don’t forget that the rated discharge constant is about 4.7% lower than the charge constant for “reasons” (related to the buffer size...). So in order to get mile for rated mile rolloff of your range, you will need to do better than about 1/(1.047)*265Wh/mi = 253Wh/mi, with the 20” wheel constant. Yes it is confusing...

 

[Tholland]

Alan, you are amazing! This thread is a excellent use of knowledge. Are 100% sure that this is more so, affecting the 2020 models? Or maybe all of the fleet is seeing this change. I know my 19 P3D+ (June) with the app slider shows 307 est miles of range at 100% car hasn’t been to 100% since July which was the only time. Now today I’ll check when I get off work and see what the estimate is in the app vs the rates line in the car screen. I find this information very interesting. As our LRDM 3 with 19 wheels only shows 297-300miles at 100% charge and that was noticed a few update ago while prior to that update it would go to 308ish. Your explanations of the less range but increase of range made sense. But I’m just curious if this math is also effecting the 18-19 models as well. I figured the same as someone else on here. The EPA rated numbers are almost certainly until the car stops moving which of course people should NOT do.

 

[toolman335]

I love all of this information!
There's no need to overthink it though. There have countless threads about this topic, which means that most people experience a change in range. at 100% mine has gone from 310, down to 293, and back up to 307(it seems to have settled at this level for the last month).
If you think too much you won't enjoy the car. In the winter we won't get close to 310 anyway, so don't worry about it.

 

[Tholland]

Oh yeah for sure. I don’t even use the mile. I just the % because you will drive yourself crazy looking at the miles. In winter it’s just a toss up. But I do go over 80% unless I absolutely need to. But I’m just eating up this range info. It’s great to know. I’m nerdy that way.

 

[AlanSubie4Life]

Are 100% sure that this is more so, affecting the 2020 models?

Definitely not 100% sure. However, I have not seen an Energy Consumption screen picture from a 2018/2019 which demonstrates a new constant. (Using the standard calculation ProjRange*RecentEfficiency/RatedMilesRemaining.)

And I have seen no change in range on my 2018 3P+ when I change wheel configurations (that’s the key behavior which is new). I have the same 300 rated miles that I’ve settled at for the past few weeks - no sudden changes.

 

[ElectricIAC]

I stopped using mile counter a long time ago as our Model 3’s get nowhere near rated wh/mi anyway.

 

[Tholland]

Definitely not 100% sure. However, I have not seen an Energy Consumption screen picture from a 2018/2019 which demonstrates a new constant. (Using the standard calculation ProjRange*RecentEfficiency/RatedMilesRemaining.)

And I have seen no change in range on my 2018 3P+ when I change wheel configurations (that’s the key behavior which is new). I have the same 300 rated miles that I’ve settled at for the past few weeks - no sudden changes.

ahhh ok Gotcha. I’ll give it a try with both of our cars. But sounds to be a 2020. Out DMLR 3 has settled around 300 as well

 

[VQTRVA]

To measure your battery, it needs 2 reference points: 0% and 100% state of charge. Going down to 0% is not advisable because the low state of charge can permanently damage your battery. The same with "PROLONGED" 100% (It's fine for the purpose of road trips and that's not considered as too long.)

If no one offers it the 2 needed references for proper calculations, the battery gauge would make an educated guess.

I think Tesla has made a compromise by instructing owners to charge their cars to 90% daily so it can do a better guess without actually experiencing those 2 damaging referenced points 0% and 100%

So, to get an accurate reading for your battery gauge, you can provide it with those 2 damaging State of Charge. Doing once might not be enough to train the calculation. You might have to repeat that several times. Don't blame me if you killed your battery in the process.

I'm starting to believe this more & more recently with my AWD.

Been getting in the 220 miles range @ 80% charge.
Given the logic above if the BMS is thinking 90% approximates 100% then that math is: 310 x 0.90 = 279
And 80% of the approximate 100% range is: 279 x 0.80 = 223 miles. Which is what I have been seeing since the latest 2019.40.50.x updates.

 

[iaaaaan]

Do you guys think this is related to the same things you guys are discussing? I’ve seen a sudden drop recently too.

 

[AlanSubie4Life]

Do you guys think this is related to the same things you guys are discussing? I’ve seen a sudden drop recently too. View attachment 495567

Yes. What type of vehicle?

 

[iaaaaan]

2020 Performance model 3

Yes. What type of vehicle?

 

[AlanSubie4Life]

2020 Performance model 3

Yeah, not too surprising...pretty much had to be for 293 miles unless someone is running 20” aftermarket.

If you want, try changing to 18” wheel config in the Service menu and then run that for a bit to see what Stats says your range is. Note this will screw up the estimates of arrival charge in the trip planner until you swap back to 20”.

 

[Tholland]

Alan, I believe you are correct. The 2018-2019 must be using a different constant than the 2020.
This is our 2019 June P3D+ But if I did the math right the constant came out to 269.9 (270) which the ~5wh/rm over it puts its at 265 constant which is the same as the 2020. But if I use the last 15 miles I get ~240 constant. Hmmm this is interesting! And slightly triggering my senses l

 

[AlanSubie4Life]

Alan, I believe you are correct. The 2018-2019 must be using a different constant than the 2020.
This is our 2019 June P3D+ But if I did the math right the constant came out to 269.9 (270) which the ~5wh/rm over it puts its at 265 constant which is the same as the 2020. Hmmm this is interesting! And slightly triggering my senses l
View attachment 496009 View attachment 496012

I have a 2018 3P+ so that constant is still right around the 245Wh/rmi value even with 20s selected. I guess your math was off somehow?

The product of the graph numbers is always the remaining battery energy including buffer.
239Wh/mi*181mi = 43.3Wh
Divide by 177rmi:
43.3kWh/177rmi = 244.4Wh/rmi (close enough to 245Wh/rmi)

Same answer for the other pic:
225Wh/mi*192mi = 43.2Wh

So still 244Wh/rmi. Which is close enough. If you do this more times, or use km, and attempt to capture the rollover on your rated miles you can get better precision. But it’s right around 245Wh/rmi still. Only 2020 changes so far at least...

 

[Tholland]

I have a 2018 3P+ so that constant is still right around the 245Wh/rmi value even with 20s selected. I guess your math was off somehow?

The product of the graph numbers is always the remaining battery energy including buffer.
239Wh/mi*181mi = 43.3Wh
Divide by 177rmi:
43.3kWh/177rmi = 244.4Wh/rmi (close enough to 245Wh/rmi)

Same answer for the other pic:
225Wh/mi*192mi = 43.2Wh

So still 244Wh/rmi. Which is close enough. If you do this more times, or use km, and attempt to capture the rollover on your rated miles you can get better precision. But it’s right around 245Wh/rmi still. Only 2020 changes so far at least...

I see where I went wrong. It was the 43.2 kw. Thanks so much. I like figuring out stuff like this. Gives you a good handle on how things change and evolve. Thank you. You profile picture makes me miss my Honda Civic type r but that’s for another thread lol.