Yeah, it doesn't do that. It's lying. PM me your email and I'll send he Excel file.True nominal zero is below dashboard zero, just like an ICE car has gas left in the tank below the “E” line. Nominal zero does not include anti-brick buffer, they don’t let you go below nominal zero. They use the EPA number minus a ~5% all the way down, so that there is a ~5% amount available to drive after the dash says zero.
A quick chart to illustrate this. It should look very familiar.
Numbers approximated based on rough memory of people posting, but this is a quick 15-second attempt to chart what’s going on and what people (like @AWDtsla recently) are interpreting as “many fudge factors” that are in fact likely just 3 simple lines.. Two are parallel with the same slope, the other declines more steeply.
y-axis is range (miles) remaining, x-axis is energy (kWh) used, starting at 0 for 100% SoC, ending at 55-ish.
To explain the constants in this example loosely based on Model 3 SR+ (based on recollection),
Again, chart just meant to be a rough, quick, illustrative example, but roughly uses correct-ish numbers IIRC.
- 240 represents EPA range displayed at 100% SoC before any pack energy used.
- -(1/.219) represents consumption of 219 Wh/mi, in mi/kWh (slope is y/x aka mi/kWh on this chart)
- -(1/.208) represents a worse* consumption of 208 Wh/mi, in mi/kWh used to tick down the displayed miles more quickly to build up a buffer to use below dashboard zero (this is 219 - 5%).
- (1-0.05) represents setting aside 5% of the range to save for below dashboard zero (208 Wh/mi is the same 95% of 219 Wh/mi, I should have used 219*(1-0.05) for consistency actually instead of 208). The stats apps call this “usable” it looks like, but I believe a more accurate term is “above dashboard zero”. We’ve seen that there is much more usable beyond this “zero”. Nominal is all usable and the EPA test used it all until nominal zero where the hidden anti-brick buffer kicks in.
*Worse here is a “better” or lower consumption #, meaning you’d have to drive at that better-than-rated rate to see the displayed miles above zero tick down at the same rate as real miles driven.
View attachment 429270
View attachment 429271
Source of charts: Click here to recreate yourself for your own car in Wolfram Alpha and you can play around with the constants I described above to make your own version.
[EDIT: I updated that link with 219*(1-0.05) used instead of 208 so it’s easier to plunk in your own numbers by changing 240 to your range, and 219 to your car’s internal consumption constant number in Wh/mi, and the end kWh from 53 to 75 or 100 or whatever. Original link for above charts here]
Note that attempting to divide “displayed miles remaining” by underlying pack energy isn’t fruitful here. You need to use “consumed displayed miles” instead.
The formula for kWh (x) from miles (y), based on:
y = 240 - (1/.208)x,is:
x = (240 - y) miles * 208 Wh/miSo for above numbers, if I see “100 displayed miles” remaining, I take that away from 240, so I’ve used 140 * 208 Wh/mi = 29.1 kWh. The pack should show (nominal 100% capacity in kWh) minus (29.1 kWh used) as the remaining kWh, say 52.5 - 29.1 = 23.4.
If you do it like this, it should be linear, reproducible, and no multiple fudge factors.
If you instead go: 100 * 208 = 20.8 kWh, or 100 * 219 = 21.9 kWh you don’t get the right answer, and might think “this fudge factor is changing the whole way down, I need to use 234 now?!”
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This is why you can't get 'rated range'
- Thread starter David99
- Start date
The only explanation is that for the EPA testing, they allowed the test car to go lower than dash zero and use up that 4kw buffer. OR they had special software that set zero at nominal remaining=zero. If it was the latter, you may recall a certain company that just got in trouble for fudging a certain test.....
darth_vad3r
Well-Known Sith
Our cars can go below dash zero too. Lots of posts about this. I linked one above showing -7% on the energy chart.
Elon said 5 to 15 miles range usable below zero here:
https://mobile.twitter.com/elonmusk/status/1000456410944061440
That was spring 2018. More recently April 2019 said a more conservative “5 miles past zero”:
https://mobile.twitter.com/elonmusk/status/1120227783735566336
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That seems normal, right? Larger battery, larger buffer?
Also, I thought wk057 found some 100kw packs were up at 100.5 and 101kwh before the buffer?
Wk057 said his 100kWh battery had a 4kWh buffer and there are others who have posted they have 4 I'm pretty sure. He made a big deal (saying they finally meet the nameplate capacity) that the battery is 102 nominal with a 4 buffer for 98 usable, but mine is about 98 nominal with a 5 buffer for 93 usable.
My car is using 295 Wh/mile for range calculation, and 93/.295 = 315 the advertised range. But if wk057 had 98 kWh his would have a 332 mile range in a p100d. I thought the p100d was rated higher than 295 Wh/mile.
Some others with a 100kWh pack with a 4kWh buffer
Model X 100D not 100kWh battery
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aerodyne
2 of 3 EV's - Defect Free!
Very useful thread, although it took some repeating of key points to convince some...
One thing I would like to emphasize is that Tesla's approach for rated range can also be used to mask degradation.
Using S85D numbers, 30% degradation on a nominal 81.5 KwH pack leaves 57.05KwH remaining. Minus the 4 KwH buffer, is only 53.05 usable. That is a 35% reduction in usable capacity.
It is an interesting "coincidence" that the M3 with the 30% degradation warranty no longer shows the full and usable pack sizes on the CAN bus...
So, a SC could reject a warranty claim in this situation .
One thing I would like to emphasize is that Tesla's approach for rated range can also be used to mask degradation.
Using S85D numbers, 30% degradation on a nominal 81.5 KwH pack leaves 57.05KwH remaining. Minus the 4 KwH buffer, is only 53.05 usable. That is a 35% reduction in usable capacity.
It is an interesting "coincidence" that the M3 with the 30% degradation warranty no longer shows the full and usable pack sizes on the CAN bus...
So, a SC could reject a warranty claim in this situation .
The CAN bus does show the full pack and buffer size for the M3, so it's just a subtraction to get the usable value. So it's hard to say why they don't show the usable value directly. They're not really hiding anything.
I don't know if Tesla ever defined exactly what 30% degradation means, so I think you just have to assume it would mean 30% reduction in original rated miles at 100%. But they should clarify that.
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aerodyne
2 of 3 EV's - Defect Free!
Sorry, not an M3 owner, it was reported that the M3 did not show the buffer, and I did not fact check.
If they do define degradation based on RM, and if RM is only attainable by using the buffer, I would cry foul...
I still support and love Tesla, as it was in 2015. Not the Tesla post 2018.
If they do define degradation based on RM, and if RM is only attainable by using the buffer, I would cry foul...
I still support and love Tesla, as it was in 2015. Not the Tesla post 2018.
aerodyne
2 of 3 EV's - Defect Free!
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