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

[supraphonic]

A follow-up for those interested: I had a call with Tesla service earlier this week where virtual diagnostics confirmed I'm at 12 percent (!) capacity loss after five months and 5,100 miles. Tesla's expectation is that capacity loss generally reached 10 percent and settles out, but that usually happens over the course of a year or so. We'll have to wait and see what happens with mine.

One month and roughly 1,000 miles later and it's definitely only continuing to get worse. Photo linked below was on a little San Diego County loop starting from 90 percent in basically perfect weather conditions, properly inflated tires, and a mix of city and highway driving averaging 225 wh/mi.

Back of the envelope math leaves me with 37.8 kWh effective capacity and 166 miles of range when driven *very* delicately, down from the original software-locked 50 kWh and claimed 220 miles of range, just shy of six months since delivery.

 

[AlanSubie4Life]

One month and roughly 1,000 miles later and it's definitely only continuing to get worse. Photo linked below was on a little San Diego County loop starting from 90 percent in basically perfect weather conditions, properly inflated tires, and a mix of city and highway driving averaging 225 wh/mi.

Back of the envelope math leaves me with 37.8 kWh effective capacity and 166 miles of range when driven *very* delicately, down from the original software-locked 50 kWh and claimed 220 miles of range, just shy of six months since delivery.


View attachment 590703

1) Important: Quote rated miles @100% (when charged to 100%, not extrapolated!!!), and starting and ending rated miles, for better accuracy on your calculations).
2) I'm going to assume you drove continuously on this trip without stopping (otherwise the result is potentially invalid due to loss while in park). You can only extrapolate numbers on continuous drives, unless you carefully account for energy lost while parked (and there's always some inaccuracy when doing such accounting).

Running the numbers:

Energy between 100% and 0%: (27.7kWh)/(0.9-0.16) = 37.4kWh

Total capacity: 37.4/0.99/0.955 (4.5% buffer and ~1% loss on meter) = 39.6kWh (includes the buffer).

Your original SR (I can't say exactly what it is, but the EPA test was ~50.2kWh, but that gets scaled down slightly for these numbers) was around 49-50kWh, including the buffer.

So about 20% capacity loss making the assumptions above (it would be good to get confirmation that it was a continuous drive and get your rated miles at 100%, to ensure this number is correct...it seems very high).

If correct, your car should indicate 181 rated miles when charged to 100%, and about 163 rated miles at 90%.

 

[camalaio]

1) Important: Quote rated miles @100% (when charged to 100%, not extrapolated!!!), and starting and ending rated miles, for better accuracy on your calculations).
2) I'm going to assume you drove continuously on this trip without stopping (otherwise the result is potentially invalid due to loss while in park). You can only extrapolate numbers on continuous drives, unless you carefully account for energy lost while parked (and there's always some inaccuracy when doing such accounting).

Running the numbers:

Energy between 100% and 0%: (27.7kWh)/(0.9-0.16) = 37.4kWh

Total capacity: 37.4/0.99/0.955 (4.5% buffer and ~1% loss on meter) = 39.6kWh (includes the buffer).

Your original SR (I can't say exactly what it is, but the EPA test was ~50.2kWh, but that gets scaled down slightly for these numbers) was around 49-50kWh, including the buffer.

So about 20% capacity loss making the assumptions above (it would be good to get confirmation that it was a continuous drive and get your rated miles at 100%, to ensure this number is correct...it seems very high).

If correct, your car should indicate 181 rated miles when charged to 100%, and about 163 rated miles at 90%.

This assumes that the SR (non-plus) degrades in range vs. capacity like the other models. Maybe you know to make that assumption, but no other EV nor PHEV with a top-buffered battery works like that. They'll use, say, 80% of their capacity range when new, and once the battery is degraded to roughly 80%, start using 100% of it for example. The whole way down it will look like no degradation occurred, until that 80% point.

We know the SR is top-buffered, but do we know for certain it keeps that top buffer as it degrades (and thus the normal calculations hold)? And if it does, is it a relative buffer or an absolute buffer?

I personally really want to know even if it impacts so few people. I'm not even in that bucket!

 

[MP3Mike]

This assumes that the SR (non-plus) degrades in range vs. capacity like the other models. Maybe you know to make that assumption, but no other EV nor PHEV with a top-buffered battery works like that. They'll use, say, 80% of their capacity range when new, and once the battery is degraded to roughly 80%, start using 100% of it for example. The whole way down it will look like no degradation occurred, until that 80% point.

We know the SR is top-buffered, but do we know for certain it keeps that top buffer as it degrades (and thus the normal calculations hold)? And if it does, is it a relative buffer or an absolute buffer?

Yes, we know, it is how Tesla has done it from the start with the Model S 40 (60 pack), Model S 60 (70/75 pack), Model S 70 (75 pack). The buffer is a constant percentage. If they released the capacity as the battery degraded they couldn't sell you the upgrade to an SR+, as there might not be anything left to unlock.

In fact in the Model S 40 they didn't even hide it. They locked the charge slider so you couldn't set it higher than ~67%.

 

[AlanSubie4Life]

We know the SR is top-buffered, but do we know for certain it keeps that top buffer as it degrades (and thus the normal calculations hold)? And if it does, is it a relative buffer or an absolute buffer?

All the evidence so far seems show it works as @MP3Mike indicates.

There are very few such vehicles, so the definitive info on *exactly* how it works on an SR (in the form of SMT data, etc., will likely remain unknown.

I think my assumptions are safe, but they definitely are assumptions, and based on just a couple of data points to date showing that SR vehicles show degradation/capacity loss in a manner similar to all the other vehicles.

 

[supraphonic]

1) Important: Quote rated miles @100% (when charged to 100%, not extrapolated!!!), and starting and ending rated miles, for better accuracy on your calculations).
2) I'm going to assume you drove continuously on this trip without stopping (otherwise the result is potentially invalid due to loss while in park). You can only extrapolate numbers on continuous drives, unless you carefully account for energy lost while parked (and there's always some inaccuracy when doing such accounting).

All good points. Much as I’ve been told we can trust the BMS to deliver accurate readouts, I’m going to take it up to 100 percent overnight, and I’ve got some work errands to run at a few places around the county tomorrow so I’ll see where we can get. I’ve set another service appointment to see if we can get to the bottom of this with the data Tesla has on their backend.

 

[AlanSubie4Life]

All good points. Much as I’ve been told we can trust the BMS to deliver accurate readouts, I’m going to take it up to 100 percent overnight, and I’ve got some work errands to run at a few places around the county tomorrow so I’ll see where we can get. I’ve set another service appointment to see if we can get to the bottom of this with the data Tesla has on their backend.

Yeah, though there may be some error, your situation sounds pretty bad. If you're running errands just remember to take pictures of the trip meter for each segment, and capture the starting rated miles and ending rated miles for each segment.

But frankly, as far as I can tell, the rated miles @100% number will tell you everything you need to know (you can do all the tracking/pictures by segment, but it will all support the result that your available energy including buffer is about (219Wh/rmi) * (rmi @100%) - so you don't actually have to gather that segment info, usually, assuming the BMS is not really having huge issues - which I doubt it is).

The good news is that it seems there is a decent chance you'll meet the criteria for battery replacement in relatively short order (within the next couple years).

 

[supraphonic]

Yeah, though there may be some error, your situation sounds pretty bad. If you're running errands just remember to take pictures of the trip meter for each segment, and capture the starting rated miles and ending rated miles for each segment.

But frankly, as far as I can tell, the rated miles @100% number will tell you everything you need to know (you can do all the tracking/pictures by segment, but it will all support the result that your available energy including buffer is about (219Wh/rmi) * (rmi @100%) - so you don't actually have to gather that segment info, usually, assuming the BMS is not really having huge issues - which I doubt it is).

The good news is that it seems there is a decent chance you'll meet the criteria for battery replacement in relatively short order (within the next couple years).

More questions than answers after a charge up to 100 percent. I'll let it sit here for a couple hours to let the BMS get a good capacity reading for a benchmark, but this is a wildly optimistic number given my recent history.

 

[AlanSubie4Life]

More questions than answers after a charge up to 100 percent. I'll let it sit here for a couple hours to let the BMS get a good capacity reading for a benchmark, but this is a wildly optimistic number given my recent history.

Not really! This is mostly good news! You do have capacity loss, but it's not that bad - only 6.5% or perhaps as high as 8% (this is basically "normal").

Remember, your recent history has NOT been carefully tabulating your energy losses WHILE IN PARK. They can be ENORMOUS - easily several kWh in a single day depending on configuration.

As you take pictures today, we'll need a picture at the beginning AND end of each segment, clearly showing the trip meter results (since x:xx time) for each segment, and ALSO the starting AND ending rated miles for each segment. Ideally, capture the time in each picture, as well (will allow us to calculate your rate of energy loss while parked (the power draw when parked)) - but that requires a picture of the whole screen and may not be preferred for privacy reasons.

It's not enough to simply take one picture at the end of each segment, or at the end of the day, showing the day's results. You have to take a picture every time you exit the car, and every time you enter the car. Showing the "since time x:xx" and the rated miles in every picture.

If you do this fastidiously, for a nice long day of driving where you discharge to a low SoC, we will be able to analyze the results here and hopefully fully explain exactly what is happening. Obviously it's easier to simply to a single continuous drive from 100% to ~10%, but that can be difficult to do unless you're on a road trip.

To me it looks like your battery capacity including buffer is 45kWh (vs. about 49kWh when new (nominally it's ~48kWh for SR before capacity loss shows, AFAIK) ). So that's where the 6.7% to 8.2% capacity loss estimates come from. But we'll see.

The pictures (including the trip meter and the rated miles gauge!!!) will let us know if there is any error in our estimates, though.

 

[supraphonic]

Not really! This is mostly good news! You do have capacity loss, but it's not that bad - only 6.5% or perhaps as high as 8% (this is basically "normal").

Remember, your recent history has NOT been carefully tabulating your energy losses WHILE IN PARK. They can be ENORMOUS - easily several kWh in a single day depending on configuration.

As you take pictures today, we'll need a picture at the beginning AND end of each segment, clearly showing the trip meter results (since x:xx time) for each segment, and ALSO the starting AND ending rated miles for each segment. Ideally, capture the time in each picture, as well (will allow us to calculate your rate of energy loss while parked (the power draw when parked)) - but that requires a picture of the whole screen and may not be preferred for privacy reasons.

It's not enough to simply take one picture at the end of each segment, or at the end of the day, showing the day's results. You have to take a picture every time you exit the car, and every time you enter the car. Showing the "since time x:xx" and the rated miles in every picture.

If you do this fastidiously, for a nice long day of driving where you discharge to a low SoC, we will be able to analyze the results here and hopefully fully explain exactly what is happening. Obviously it's easier to simply to a single continuous drive from 100% to ~10%, but that can be difficult to do unless you're on a road trip.

To me it looks like your battery capacity including buffer is 45kWh (vs. about 49kWh when new (nominally it's ~48kWh for SR before capacity loss shows, AFAIK) ). So that's where the 6.7% to 8.2% capacity loss estimates come from. But we'll see.

The pictures (including the trip meter and the rated miles gauge!!!) will let us know if there is any error in our estimates, though.

Turns out I misremembered the details of the post so I only have the two summary screens from the night, but the first is just about halfway through the trip. Started from 100 percent/206 indicated miles and ended at 58 percent/120 indicated miles after a map-verified 65.2 miles of travel, following a close but not perfectly identical out-and-back route. Consumption is higher since I intentionally made this a more freeway-heavy test to figure out whether I'll safely be able to make the cross-country trip I'm planning for December. Seems like giving the battery a chance to start from higher up helped, but not by much.

End of first half score at the very beginning of the second half, after parking for about 20 minutes:

End of second half, no intermediate stops:

Quick math at the end gives me:

• (17 kWh consumed) / (100 percent battery - 58 percent battery) = ~40.5 kWh actual capacity
• (65.2 miles of range) / (100 percent battery - 58 percent battery) = ~155 miles freeway range
• Check of (40.5 kWh est)/(155 mi est) = ~261 Wh/mi est, pretty close to what's displayed

I'm texting with a Tesla virtual tech today about this, so we'll see what their data says.

 

[AlanSubie4Life]

Turns out I misremembered the details of the post so I only have the two summary screens from the night, but the first is just about halfway through the trip. Started from 100 percent/206 indicated miles and ended at 58 percent/120 indicated miles after a map-verified 65.2 miles of travel, following a close but not perfectly identical out-and-back route. Consumption is higher since I intentionally made this a more freeway-heavy test to figure out whether I'll safely be able to make the cross-country trip I'm planning for December. Seems like giving the battery a chance to start from higher up helped, but not by much.

End of first half score at the very beginning of the second half, after parking for about 20 minutes:
View attachment 591413

End of second half, no intermediate stops: View attachment 591417

Quick math at the end gives me:

• (17 kWh consumed) / (100 percent battery - 58 percent battery) = ~40.5 kWh actual capacity
• (65.2 miles of range) / (100 percent battery - 58 percent battery) = ~155 miles freeway range
• Check of (40.5 kWh est)/(155 mi est) = ~261 Wh/mi est, pretty close to what's displayed

I'm texting with a Tesla virtual tech today about this, so we'll see what their data says.

Hard to interpret this properly, because:

1) You missed critical photos: a) The picture when first starting out on your trip showing 206 rated miles with 0 miles traveled. b) The picture at the end of the first segment before exiting the vehicle.

2) You do not have your energy display set to "distance" - you have it set to "energy." Set it to distance! It's far better if you actually care about how much energy you have available (which is what we care about here). In many cases "energy" display is just fine, but not if you care about energy (ironically). Very important.

3) You do not have the trip meter set to "since x:xx". That is very important. You can't set it to "since last charge" for these calculations (though under some circumstances it can be ok). In general, it leaves too much ambiguity if we want to do these analyses.

4) We also don't know whether you spent any time sitting in the vehicle while in park (energy use in this state is not counted by the trip meter).

5) Ideally you'd like to see closer to a full discharge for better accuracy (down to 20% would be sufficient to halve the error in the estimates).

Doing the math:

Segment 1:

33.7mi*262Wh/mi = 8.83kWh

(ASSUMPTION: you used 43 rated miles, starting at 206, so you ended this segment at 79%, not 78%. Entirely possible since you sat for 20 minutes and who knows what the car was doing during that time. But again, the best thing is to set energy display to distance and take the pictures before and after each segment.)

So you used 21% of your range for that segment (not 22%).

Segment 2:
65.2mi * 255Wh/mi - 8.83kWh = 7.80kWh

This used 20% of your range (there is error on this, again, since you are not set to distance display).

I will assume you used 38 rated miles for this segment (18-19%) (we will never know). The 20% used suggests closer to 41 rated miles were used. But this is within the margin of error, given that you have % display set.

Summary:

Looks to me like you used about 16.63kWh while driving, and used about 1kWh when parked (this "while parked number is an unnecessary guess; in future you can just get the proper pictures and configuration, and we don't have to guess about the energy used while parked - we'll just know it based on the change in rated miles while parked (not the % - can't use %)).

This used 42% of your battery (not including the buffer):

(16.63kWh+1kWh)/0.42/0.99 = 42.4kWh. (The 0.99 factor accounts for the 1% low reading on the trip meter relative to ScanMyTesla readings.)

If you include the buffer:

42.4kWh/0.955 = 44.4kWh

44.4kWh/219Wh/rmi = 203 rated miles (close to your actual 206 rated miles)


Again, all very rough, but looks very consistent with a battery with 45kWh remaining, ~43kWh of which is available above 0%.

If you get all of the errors resolved in your data capture, we can analyze again. Summary:

1) Miles! Not %. Log your 100% rated miles number (it changes (generally gets smaller), so have to charge to 100% before running this experiment, and make a note of the value).
2) Trip meter: Since x:xx. (not since last charge)
3) Pictures before and after each segment, ideally IMMEDIATELY before and after exiting/entering Park.
4) Do a discharge to 20% following above procedure, and crunch the numbers. (I expect they'll extrapolate to about 43kWh not including the buffer, after inflation by 1% due to trip meter "inaccuracy.")


But I imagine Tesla will tell you your battery is just fine. Looks like about 7-8% capacity loss to me. Seems normal given the age of the vehicle. Your situation looks fine. Just have to be careful on long Supercharger legs.

 

[AlanSubie4Life]

Hard to interpret this properly, because:

1) You missed critical photos: a) The picture when first starting out on your trip showing 206 rated miles with 0 miles traveled. b) The picture at the end of the first segment before exiting the vehicle.

2) You do not have your energy display set to "distance" - you have it set to "energy." Set it to distance! It's far better if you actually care about how much energy you have available (which is what we care about here). In many cases "energy" display is just fine, but not if you care about energy (ironically). Very important.

3) You do not have the trip meter set to "since x:xx". That is very important. You can't set it to "since last charge" for these calculations (though under some circumstances it can be ok). In general, it leaves too much ambiguity if we want to do these analyses.

4) We also don't know whether you spent any time sitting in the vehicle while in park (energy use in this state is not counted by the trip meter).

5) Ideally you'd like to see closer to a full discharge for better accuracy (down to 20% would be sufficient to halve the error in the estimates).

Doing the math:

Segment 1:

33.7mi*262Wh/mi = 8.83kWh

(ASSUMPTION: you used 43 rated miles, starting at 206, so you ended this segment at 79%, not 78%. Entirely possible since you sat for 20 minutes and who knows what the car was doing during that time. But again, the best thing is to set energy display to distance and take the pictures before and after each segment.)

So you used 21% of your range for that segment (not 22%).

Segment 2:
65.2mi * 255Wh/mi - 8.83kWh = 7.80kWh

This used 20% of your range (there is error on this, again, since you are not set to distance display).

I will assume you used 38 rated miles for this segment (18-19%) (we will never know). The 20% used suggests closer to 41 rated miles were used. But this is within the margin of error, given that you have % display set.

Summary:

Looks to me like you used about 16.63kWh while driving, and used about 1kWh when parked (this "while parked number is an unnecessary guess; in future you can just get the proper pictures and configuration, and we don't have to guess about the energy used while parked - we'll just know it based on the change in rated miles while parked (not the % - can't use %)).

This used 42% of your battery (not including the buffer):

(16.63kWh+1kWh)/0.42/0.99 = 42.4kWh. (The 0.99 factor accounts for the 1% low reading on the trip meter relative to ScanMyTesla readings.)

If you include the buffer:

42.4kWh/0.955 = 44.4kWh

44.4kWh/219Wh/rmi = 203 rated miles (close to your actual 206 rated miles)


Again, all very rough, but looks very consistent with a battery with 45kWh remaining, ~43kWh of which is available above 0%.

If you get all of the errors resolved in your data capture, we can analyze again. Summary:

1) Miles! Not %. Log your 100% rated miles number (it changes (generally gets smaller), so have to charge to 100% before running this experiment, and make a note of the value).
2) Trip meter: Since x:xx. (not since last charge)
3) Pictures before and after each segment, ideally IMMEDIATELY before and after exiting/entering Park.
4) Do a discharge to 20% following above procedure, and crunch the numbers. (I expect they'll extrapolate to about 43kWh not including the buffer, after inflation by 1% due to trip meter "inaccuracy.")


But I imagine Tesla will tell you your battery is just fine. Looks like about 7-8% capacity loss to me. Seems normal given the age of the vehicle. Your situation looks fine. Just have to be careful on long Supercharger legs.

Reminder again: in spite of al the above process, it is quite unnecessary. All you need to know if your rated miles at 100%. For an SR it‘s a bit less well studied so I could be wrong, but AFAIK 206 rated miles corresponds to:

206rmi*219Wh/rmi= 45.1kWh (w/ buffer)

This is from the Constants thread.

 

[ran349]

Reminder again: in spite of al the above process, it is quite unnecessary. All you need to know if your rated miles at 100%. For an SR it‘s a bit less well studied so I could be wrong, but AFAIK 206 rated miles corresponds to:

206rmi*219Wh/rmi= 45.1kWh (w/ buffer)

This is from the Constants thread.

I believe per your table the calculation is 206 (rated miles at 100%) x 210 (charge constant for SR) = 43.26 kWh with buffer. This is consistent with his (@supraphonic) reported actual driving achievable of approx. 40 kWh, based on his pictures.

The full pack for a non-degraded SR would be roughly 220( SR new rated miles)/250 (SR+ new rated miles) x 52.5 kWh = 46.2 kWh.
This equates to a degradation for his car of 43.26/46.2 = approx. 6.4 % degradation.

As you said, this is most directly and easily determined by just looking at 100% rated miles compared to new. In this case, 206/220 = 6.4%.

In terms of degradation, his numbers seem very typical.

 

[AlanSubie4Life]

I believe per your table the calculation is 206 (rated miles at 100%) x 210 (charge constant for SR) = 43.26 kWh with buffer. This is consistent with his (@supraphonic) reported actual driving achievable of approx. 40 kWh, based on his pictures.

The SR is always super confusing since it was never scaled up in range (constant scaled down) like the SR+, AFAIK.

The old SR+ and the SR (240rmi and 220rmi, respectively) both have charge constants of 219 Wh/rmi (see the table). (AFAIK)

The new SR+ with 250-mile range has a charge constant of 210Wh/rmi. (AFAIK). Energy available is the same (219Wh/rmi*240rmi ~= 210Wh/rmi*250rmi).

So the correct ratio & kWh for SR is 220/240*52.5kWh = 48.1kWh. (The EPA test of the SR with a few thousand miles on it extracted 50.2kWh, FWIW).

I believe that is correct, anyway; I am open to corrections or data from an SR that suggest otherwise (it's super difficult to get good data points from SRs since they are so rare - maybe I should just go buy one of each model!).

Your degradation calculation is correct, though: 206/220 => 6.4% (probably a little bit more due to the initial inflated energy constant, but hard to know on that one). We can say it is at least 6.4% and that is about it. (Your first calculation is only coincidentally correct, because I believe you used the wrong 210/219 scale factor in both numerator and denominator, and they cancelled out and provided the correct result - this is important because it affects kWh available as detailed above. The second calculation (206/220) is correct both methodologically and numerically.)


I still suspect the 40kWh from his pictures is being biased down by the trip meter loss and standby losses, and numerical inaccuracies due to use of %. It's really difficult to get good data! Have to be fastidious about capturing every last kWh of loss (and temperature can't change too much, etc., etc.). We don't even know for sure whether he started his trip at 206 rated miles! (It could easily have been 203 rated miles after sitting overnight.)

Really we need to see a good data capture (pictures) in the SR car from a single continuous long trip segment (before and after!), showing definitively that the discharge "constant" is about 206Wh/rmi, not 198-200Wh/rmi like it would be for a 2020 SR+, to confirm my table is correct (I have no idea - I can only do calculations from the EPA docs and go with that, I have no ground-truthed data for SR). If we have that datapoint, then we can extrapolate and determine whether my table is correct for SR, or whether it needs correction.

I suspect the table is correct, because there were never any reports that SR owners got a nominal range boost on top of their 220-mile range (though they probably did get an efficiency boost through software drive control improvements, just like the SR+ owners - the SR+ got a LOT more efficient in the EPA tests between 2019 and 2020).

 

[ran349]

(Your first calculation is only coincidentally correct, because I believe you used the wrong 210/219 scale factor in both numerator and denominator, and they cancelled out and provided the correct result - this is important because it affects kWh available as detailed above. The second calculation (206/220) is correct both methodologically and numerically.)

Well, I think the data he provided is consistent with the 210 charge constant and 197 discharge “constant” in your table for the 2020 SR+.

The energy graph can be used to get an approximate value for the charge constant, and using his numbers he shows 209 (projected miles) /206 (rated miles) x 207( wh/mile average for selected interval) = ~ 210 wh/mile. The other 2 energy graphs he shows will give a similar number but need conversion from % to miles first.

His discharge rate calculated from his first trip graph showing 78% battery remaining, calculates 8.8294 (kWh used) / 45.32 rated miles used) = ~ 195 wh/mile (discharge “constant”).

Both these numbers, 210 and 195, are fairly close to the 210/197 values for the 2020 SR+ in your table.

I don’t believe that his car will find any significant hidden usable kWh beyond the 40 kWh or so that he has already demonstrated; maybe ~ 41 kWh maximum, but that’s it.

The easiest way to validate this would be to see an SMT readout at 100% car displayed charge. My guess is it would show 220/250 = 88% for the battery max SOC due to the capping for the SR. This would explain the 46.2 kWh maximum when new, and also would be consistent with his observed 40 kWh usable maximum, when accounting for his degradation of about 6.4%.

 

[AlanSubie4Life]

The energy graph can be used to get an approximate value for the charge constant, and using his numbers he shows 209 (projected miles) /206 (rated miles) x 207( wh/mile average for selected interval) = ~ 210 wh/mile. The other 2 energy graphs he shows will give a similar number but need conversion from % to miles first.

Great point! I forgot we had that info! It does indeed imply 210Wh/mi for the charging constant.

This means my table is wrong for the SR (2019) (EDIT: Note this is an SR 2020, which is not in my table - so the table is actually correct for SR2019), but I'm not surprised by that - the 2019 SR vehicles precede the constant change for the SR+. For sure those older vehicles had this energy graph show 219Wh/rmi (not 210Wh/rmi). That is without a doubt (documented elsewhere here). (I guess technically we never had a picture from the SR, but we had the energy graph pictures from the SR+. As I said, data on these vehicles is rare, so it has always been a confusing situation.)

HOWEVER, interesting what this implies -> the SR at one point did have 220 miles of rated range with a constant of 219Wh/rmi. 48kWh of energy, compared to 50kWh extracted by Tesla in the EPA test - very much in agreement.

Now that the constant is 210, that means the un-degraded range would have been: 220rmi(old)*219Wh/rmi(new) /210Wh/rmi(new) = 229rmi (new).

EDIT: Looks to me like 2019 SR had 220 rated miles, constant 219Wh/rmi, while the 2020 SR had 229 rated miles, constant 210Wh/rmi (see below for a more confusing possibility).

So that means he actually has:

206rmi (new) / 229rmi (old) => 10.1% loss of capacity.

All makes sense now. Also all his pictures above make sense.

I agree he likely has only: 206rmi*210Wh/rmi*0.955*0.99 = 41kWh available to be extracted (not including the buffer).

As compared to 45.6kWh when new (229rmi*210Wh/rmi*0.955*0.99 - or 220rmi*219Wh/rmi*0.955*0.99).

Still, a relatively normal (somewhat high, but within the normal distribution - probably 2.5-3 sigma or so) capacity loss. Something like 1st to 5th percentile I would guess.

Seems like I need to add a line to my table for the SR 2020 (I did not know it existed!).

Thanks for the reminder about this. I'm rusty! Forgot that this is the easy way to get the constant...

EDIT:

For @supraphonic - what was your rated miles when new?

If it was 220 rated miles, that's hard to square with all of this. It is possible for them to use a lower constant and still show 220 rated miles, but they have to do some initial energy inflation of each rated mile to hide the "extra" capacity (so effectively when new the constant is much higher). Note this is my own theory and we have no evidence of it (it's hard to get a hold of).

It wouldn't change the capacity loss though (yes, confusing - the initial energy inflation of rated miles on new vehicles IS confusing). It's almost certainly about 10% for @supraphonic.

 

[mrgoogle]

More questions than answers after a charge up to 100 percent. I'll let it sit here for a couple hours to let the BMS get a good capacity reading for a benchmark, but this is a wildly optimistic number given my recent history.

View attachment 590908

Sad to hear SR owners have a significant loss also. Maybe they used “failed but working” SR+ batteries...?? Like a lower treshhold to scrap a pack?

I saw a 206/220(?) picture, I have 208mi but the SR+ (plus)

Still not done and will try contacting Tesla higher up.

 

[giantshark18]

Apologies if this is duplicative of what is in the other 69 pages of posts. I went through a fair number and did not see degradation like I am seeing based on the conditions.

I have a 2020 LR AWD. I have only charged to 100% twice and yesterday was the second time. When at 100% energy, the mileage range listed was 298. It was 70 degrees when I left Santa Cruz. I also noticed that my regen braking dots almost made it to the "MPH" text on the screen. This is double what I have ever seen and the dots did not fully go away until I got home after 40 miles of mountain driving (highway 17 in the bay area). It was 100 degrees for about 2/3 of the drive. I note the temps since cold weather seems to be the cause of many other folks' lower ranges and or slow rebound of regen.

I know that the range listed can vary, but this seems like a large drop even if I take that variability into account.

Thankfully, I don't care all that much, but still interested if I am seeing warranty level degradation. Is that even a thing?

 

[AlanSubie4Life]

I have a 2020 LR AWD

What is the age of the vehicle? How many miles on the odometer? What size wheels do you have? The 2020 LR AWD has different constants depending on what wheels you have selected.

If you have 19-inch wheels, this result is very normal. Even if you have 20-inch wheels it may be normal, but it depends on the age and mileage.

Regen dots are normal when the battery is full. You mentioned mountain driving - when driving downhill at high SoC, there is limited regen capacity, so it is not unusual for more regen dots to appear for both capacity reasons and "saturation" of the battery's ability to accept charge. If you are above 90% SoC you'll virtually always see some regen dots, regardless of temperature.

Also, it takes a long time for the battery to warm up. A 40-mile drive is not necessarily enough - especially if you are not going uphill!

 

[giantshark18]

What is the age of the vehicle? How many miles on the odometer? What size wheels do you have? The 2020 LR AWD has different constants depending on what wheels you have selected.

If you have 19-inch wheels, this result is very normal. Even if you have 20-inch wheels it may be normal, but it depends on the age and mileage.

Regen dots are normal when the battery is full. You mentioned mountain driving - when driving downhill at high SoC, there is limited regen capacity, so it is not unusual for more regen dots to appear for both capacity reasons and "saturation" of the battery's ability to accept charge. If you are above 90% SoC you'll virtually always see some regen dots, regardless of temperature.

Also, it takes a long time for the battery to warm up. A 40-mile drive is not necessarily enough - especially if you are not going uphill!

Here are some more details. I received the vehicle on 12/31/19 and have 6000 miles on it. I have 18 inch wheels and do not use the aero covers. I also mainly charge at home (120v) since March when I became a full time remote worker because of covid-19. Previous to that most charging was done at work via free chargepoint. I have only have supercharged about 5 times.

Regarding my commute, it is actually sea level to 3500 feet then back down to sea level. I don't have nearly as many dots when I charge to 85%