People have figured out parity at 236 or 238Wh/rmi for the 310 rated miles. I have seen people also say that with the new 325 range, parity is in the 220's, but the rated efficiency line on the energy graph was not updated to reflect the change.
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Give up on 325 Range?
- Thread starter KenR
- Start date
People have figured out parity at 236 or 238Wh/rmi for the 310 rated miles. I have seen people also say that with the new 325 range, parity is in the 220's, but the rated efficiency line on the energy graph was not updated to reflect the change.
AlanSubie4Life
Efficiency Obsessed Member
If you happen to have the thread where people posted their data (hopefully with pictures) to calculate this (with the old software), that would be cool.
I guess we'll never know what it was before, but if indeed it has changed, that does make sense...battery capacity has not changed, nor has the actual range, at least not significantly (they did say they made the vehicle slightly more efficient but doesn't appear we know how much, and that is a different, unrelated topic)..this issue of whether the range actually increased has been beaten to death in other threads in any case. But seeing a change in the Wh/rmi is the easy way to tell what actually happened, anyhow.
Just curious for the people who "have not seen" the update to 325 in their LR RWD what their Wh/rmi calculates out to be right now... If you've seen no range "increase," perhaps you still have the old Wh/rmi constant.
Method:
Warm battery (drive for 10-20 miles first). Do experiment at reasonably constant ambient temperature, not too hot, not too cold to ensure things behave "normally".
1) Make note of rated miles available. Zero the trip meter.
2) Drive around 100 miles straight without stopping and without going into park. Doesn't have to be level, round trip, or anything. You can also do a shorter trip but the result will be less accurate (can only trust the first two digits).
3) Go into park, immediately make note of the trip meter miles & displayed Wh/mi, and the final rated miles available.
Wh/rmi = (Trip meter miles * Wh/mi ) /( Initial Rated miles - Final Rated miles)
Probably good to report the Wh/mi for the captured data too, since there is a claim the meter is a bit inaccurate at low consumption.
....
As I said, the video posted with the SR+ provides the necessary data for the SR+:
WeBackTesla
Works out to 215Wh/rmi if you look at the beginning and end of the outgoing trip. It's quite definitive so that's a good data point. I'd expect the LR RWD to be pretty similar.
The Model 3 Performance is very close to 230Wh/rmi. I've done multiple trips to confirm that. The AWD is the same.
Good time for me to post my latest TeslaFi Battery Chart:
The slow rise at ~17k miles coincided with the increased range update. Never quite got up to 325 miles; capped at around 315 miles.
The huge drop at ~21k miles was immediately after depleting to around 5%, sat at low SoC for a day or so, then charged up to 100%. I wonder if it was a "recalibration" to actual levels or because the battery actually degraded that much overnight due to the "abuse." Who knows...
The slow rise at ~17k miles coincided with the increased range update. Never quite got up to 325 miles; capped at around 315 miles.
The huge drop at ~21k miles was immediately after depleting to around 5%, sat at low SoC for a day or so, then charged up to 100%. I wonder if it was a "recalibration" to actual levels or because the battery actually degraded that much overnight due to the "abuse." Who knows...
I don't have the references handy. What I remember is that the people had done multiple nonstop long distance drives to figure out the 100-0% pack capacity.
Edit... References... LR Battery - Usable Capacity Rating and Rated Wh/mile
LR Battery - Usable Capacity Rating and Rated Wh/mile
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I have a July 2018 Build LR AWD and I only get 270 miles when I charge 90%. I have asked Tesla service about it, and they said my car is not calculating it right and wait for the next update. This was like 5 updates ago. I give up!
Thunder7ga
Member
About what date was that drop? Firmware? I saw something similar all of a sudden in mid-April nearly in sync with getting 2019.8.5.
AlanSubie4Life
Efficiency Obsessed Member
Thanks. Poking around, it looks like @ratsbew got about 235Wh/rmi pre-update in an LR RWD but I don’t see definitive numbers in his post on that from August 2018. A few screen captures but hard to say definitively. But 235Wh/rmi seems likely pre-update.
Seems about right. Multiple data points in threads above with 235Wh/rmi for AWD (and of course you'd expect the LR RWD and AWD to be identical Wh/rmi, pre-update). That’s an upper limit. My 230Wh/rmi was on a shorter discharge so there is room for error. Definitely 230-235Wh/rmi is the number. Hasn’t changed post-update of course since there was no 310->325rmi change.
And looks like about 215Wh/rmi for the SR+ with video evidence.
So all we need is the LR RWD post-update...
My guess is it is now closer to 220Wh/rmi in the LR RWD which would align roughly with the rated range increase (would scale 235Wh/rmi to 225Wh/rmi). Separately, due to the efficiency update, it might be a little easier to actually get the Wh/mi number lower post-update, so to some extent this would be a “real” range increase (but largely unrelated to the displayed miles of course).
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Yeah, I am post update on my LR RWD and get 323 rated miles at 100% SOC. I don't have time to do a long drive to test...let me rephrase, my wife and kids wouldn't allow the time for it, haha.
AlanSubie4Life
Efficiency Obsessed Member
Fair enough! You can get reasonable certainty of the first two significant digits if you are careful, with a 20-mile drive or so.
For shorter experiments, I warm up the battery with some driving, then wait for a clickover on rated miles, immediately reset the trip meter, and then drive and make note of the final numbers. This gets rid of rounding error on the rmi at one end. The other end is harder...you have to immediately go to park as soon as you see an rmi click over.
I also don’t like to end the experiment with a large regen event, since there seems to be hysteresis on the rmi indication (it does not go up with regen events unless they are *very* large). So that hysteresis introduces error because it is reflected in the trip meter but not on the rmi indication. (For example after a long hill on my way to work, I can drive 3-4 miles (at 250Wh/mi in a P3D) on the flat without any change to my rated miles display. Does not happen for the same segment if I did not come down the hill.)
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darth_vad3r
Well-Known Sith
Or with video you can “end” the experiment on the fly without going into park, and you can actually “end” it multiple times to see if you get variations.
When I last tried this on a short trip I reset the “since” trip meter while on the highway as soon as I saw the km tick down, and then took note of the km and Wh/km when another km ticked down near the end of my highway route before slowing down and having high regen for the exit.
Using this I got lower numbers than you have though.
Display: 335 km -> 310 km, trip: 19.6 km,165 Wh/km
3234 Wh / 25 km = 129.36 Wh/km = 208.18 Wh/mi
(SR+)
I wonder if this technique yields different results across different ranges of SoC due to the car possibly adjusting the rated miles ticks differently.
AlanSubie4Life
Efficiency Obsessed Member
The problem with not going into park is as you know, the trip meter doesn't update continuously. So the update may not coincide with the rated miles decrease (it's likely to lead to a slight undercount on the Wh used). It's not necessarily a huge error, and becomes insignificant for a long run, of course. And a video of course makes it easier to pick a "good" datapoint.
I think there is very likely some SoC non-linearity. Though generally I've been pretty surprised how linear it has been for me.
jelloslug
Active Member
So are you just looking at the number on the screen or are you actually trying to drive 325 miles?
AlanSubie4Life
Efficiency Obsessed Member
On the upside it almost certainly makes no difference for you (you'd have to measure the Wh/rmi constant, as described above, to see - if that's low (like 220Wh/rmi or whatever - not 235Wh/rmi) AND you "only" have 312 rated miles at a full charge, you might have battery degradation - but I very much doubt that).
Anyway, unlikely to be a problem at all or have any impact on your actual range, unless you have also not received the motor drive efficiency update (unclear whether that might not be rolled out to all LR RWD VINs).
In fact, if you're at 312 rated miles for a full charge with 235Wh/rmi as your empirical constant for your car (only you can determine that), you have a great battery, and potentially better range than quite a few users - or at least the SoC estimation thinks so!
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darth_vad3r
Well-Known Sith
Ya, max 0.1km in my case over 25km ~0.66 Wh/km possible error. I think I actually saw the trip tick up 0.1km after seeing the km tick down.
Going into park leads to /more/ error on the “end km” not being near a rollover point IMO, so I think this method of on-the-fly start and end is more accurate than going to park. If I go to park, display will be farther from the theoretical X.499 it is at when we see it tick down since I have to drive a bit to park and that will likely involve regen too.
Trying to catch the displayed distance at a rollover is attempting to simulate the decimal point accuracy the trip meter is already giving us, narrowing a +/- 0.5km (or +/- 0.8km if you use miles
) down to maybe only +/- 0.1-0.2km on both start and end. If I then read the trip meter 0.1km too early or too late I’m in the same margin of error.My short-trip number is suspiciously close to exactly 95.0% of the number I have for the car’s charging Wh/km. This makes me think maybe there’s some 5% loss somewhere, or the car is pilfering 5% of the energy “used” in the display into the infamous “energy buffer” as you drive down the SoC for later use for any adjustments in SoC estimates and/or to drive below “dashboard zero”.
Ya, max 0.1km in my case over 25km ~0.66 Wh/km possible error. I think I actually saw the trip tick up 0.1km after seeing the km tick down.
Going into park leads to /more/ error on the “end km” not being near a rollover point IMO, so I think this method of on-the-fly start and end is more accurate than going to park. If I go to park, display will be farther from the theoretical X.499 it is at when we see it tick down since I have to drive a bit to park and that will likely involve regen too.
Trying to catch the displayed distance at a rollover is attempting to simulate the decimal point accuracy the trip meter is already giving us, narrowing a +/- 0.5km (or +/- 0.8km if you use miles
My short-trip number is suspiciously close to exactly 95.0% of the number I have for the car’s charging Wh/km. This makes me think maybe there’s some 5% loss somewhere, or the car is pilfering 5% of the energy “used” in the display into the infamous “energy buffer” as you drive down the SoC for later use for any adjustments in SoC estimates and/or to drive below “dashboard zero”.
Hey, curious...so when in miles, the Wh/mile updates every 1/10 of a mile. What is the update rate when in km?
darth_vad3r
Well-Known Sith
Every 0.1km tick update in the trip the Wh/km updates.
Internally the car is continuously tracking an odometer and a watt-hour-meter, it just updates the display with progressive “snapshots” as your distance increases.
Nice, so then any test I should do in km to give a little more accuracy, haha. I'll take every decimal point I can get!
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