Right, I was mis-remembering that, thinking the NCA cars were 262 and we just got their leftover window stickers. Now that I think about it, there was a rumor that Tesla was going to software-unlock some of the buffer in the early LFP cars to increase the 253 mile range to 262 miles. That never happened, so the prevalence of the 262 number for those cars is even more confusing.
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Model 3 SR+ LFP Battery Range, Degradation, etc Discussion
- Thread starter Baluchi
- Start date
Right, I was mis-remembering that, thinking the NCA cars were 262 and we just got their leftover window stickers. Now that I think about it, there was a rumor that Tesla was going to software-unlock some of the buffer in the early LFP cars to increase the 253 mile range to 262 miles. That never happened, so the prevalence of the 262 number for those cars is even more confusing.
It does.
It tell us what we have been saying, that Tessies ”usable capacity” includes the buffer.
We know that Nominal full pack is the the total capacity including the buffer.
AlanSubie4Life
Efficiency Obsessed Member
For completeness, prior info points to 54.7kWh for the degradation threshold. So that would be 216Wh/mi for the charging constant. (So line on the Energy Screen would be at around 221Wh/mi.)
Is your US made SR+ LFP charging to 253 or 262?
In the European LFP vehicle, I understand that the rated energy per mile is essentially identical to the US NCA vehicle. So I do not believe there is any reason to believe that the US LFP vehicle will be different. It appears the US and European vehicles both already have the increased capacity...
teslamotorsclub.com
51.9/54.7*253rmi = 240rmi so that checks out as well.
Interestingly I couldn't find any EPA documents for this specific vehicle. They must exist but maybe I missed them.
Just some more data on the 45 psi experiment. The trip meter I reset after increasing tire psi from 42 to 45 has now registered around 2500 miles, and for those miles indicates a usage of 220 wh per mile. (It was at 221 wh per mile covering a 14-month period immediately previous to this latest trip meter and with tires inflated to 42 psi.) So right now l’m still thinking either the change to 45 psi didn’t change the wh usage much at all, or more likely, dialed the usage down by 2 or 3 wh, most of which was negated by more aggressive driving on my part over the past 4 months…
The way to test it would be to drive a ~50 -100 mile round trip with the TP set at what ever it is now and then reduce it by 3PSI and rerun the test drive. I assume you mean 42 and 45PSI 'cold'?
Yes 42-45 would be the pressure cold. I totally agree with your test but am too lazy to go the trouble. But I will keep it mind and when real life at some point is already compelling me to drive something similar to what you are saying, I will post again!
PianoAl
Active Member
I've seen significant differences in efficiency for no reason that I can see. For example, for the 23 mile drive I just took with a surfboard on the rack, it was 324 wh/mile*. For a seven hour drive with the same surfboard, it was 250 wh/mile. 280 for the last several thousand miles.
IOW, it's hard to test accurately.
*I did floor it at one point.
Ii have to appreciate the final asterisk point! I floored it yesterday for approximately 1.5 seconds, and occasional outbursts like like that can only be smoothed out over the course of longer time periods and distances, from my point of view.
How much flak do you absorb because of being a surfing Tesla owner in what I assume is a fishing/ logging (or state prison) oriented rural area with freezing cold ocean water? Do you catch more flak for driving a Tesla or more flak for surfing?
Don't rely on the cars display of range to change in proportion to actual battery degradation and real loss of range. My 2016 Model S has had a large loss (~30%) of actual battery capacity and actual range. Meanwhile, the cars display of range has only diminished 5% to 10%. I would make sure that your "Tessie" app isn't using the same erroneous data before trusting its values.
AlanSubie4Life
Efficiency Obsessed Member
Do you have the details on this? I have no idea how 2016 vehicles and Model S vehicles dealt with capacity loss, whether used a top buffer, or used a degradation threshold like Model 3/Y (and new Model S), etc.
I have seen numerous posts on different locations about model S getting stranded, because they lost the last 10-30 miles very quick and then the cars stopped.
It do not seem extremely unusual that this happens.
If it do, it most probably comes from a overestimate from the BMS.
In @Peter Lucas case it looks very much.
I would not guess the real loss is 30%, knowing what is needed to achieve 30% loss.
I have idea of a technique to calculate the real capacity. Using SMT (Scan My Tesla) makes it very exact but it can be done without, only using the screen also.
Charge to 70-100% or so. Not important.
Let the car sleep one hour after the charge. No Sentry, no peeking in the app, no doors opened etc. Let it sleep.
Note the indicated SOC % and maybe also the indicated range.
Then drive at least 30% indicated, (50% or more if possible without SMT, but make sure not to run it dry).
When the drive is finished and the car is in park, note the new SOC % and indicated range.
Again, let the car sleep one hour. No Sentry, no peeking in the app etc.
After this, note the SOC% and the indicated range.
The SOC will be messured by the cell Voltage during/after the sleep, and the correct SOC will be shown.
The initial sleep after the charge/before the drive is to ensure that the initial SOC is correct by cell voltage measurement.
The sleep after the drive is to, again get the cell voltage measured SOC.
If the BMS overestimates the capacity, the BMS estimate* when parking will be a higher SOC than the correct and a clear drop will happen.
If a drive use 50% indicated SOC (example, starting at 80% and ending at 30%) from a 100kWh estimated capacity the used energy is 50kWh (for now, disregard the buffer). We can read the used energy on the screen.
After sleeping one hour after the drive, the displayed SOC is for example 28%, we now know that the 50kWh used energy is about 52% of the capacity.
50/0.52 = 96.2kWh. In this case the car estimates the capacity to about 50/0.5= 100kWh but the real capacity is close to 96 kWh.
Without SMT we only have SOC in whole percent but this will give the big picture and its also possible to increase the resolution by using displayed range, km is more exakt than miles.
*) SOC can not be messured correctly other than very approximate during a drive as the battery voltage droop during load.
The shown SOC during a drive is a estimate from “initial SOC —> initial energy minus used energy which is then converted to SOC by using the estimated capacity (nominal full pack).
I do not know the 2016 but for the 2023 the buffer, and everything else works just like the M3.
There is a different approach to cell balancing I believe though, or the cells are worse. I see higher imbalance in general when parked (not the “always 4mV” as my M3P). On the other hand, I have seen 4mV during constant speed on AP, so less imbalance at load.
I have a friend with a ’18 S, I will che k it put with SMT to see if things are much different. ( I doubt it is).
ucmndd
Well-Known Member
This person has been parroting this narrative for at least a few years now without any particular substantiation. They are generally attributing phantom range loss to their inability to achieve rated consumption and bar-napkin calculations for battery capacity. You can browse their recent post history to get a feeling for the general argument.
zoomer0056
Active Member
Are you sure about this? If so, you qualify for a new battery.
I highly doubt this is the case unless you a.) exclusively supercharge, b.) have driven well over 500,000km or simply abuse the battery (which imo would be an effort).
Also it’s extremely hard to determine actual capacity loss - the range indicator in the car is NOT accurate for this. Drive the car from full to flat, but I wouldn’t recommend that either.
PianoAl
Active Member
Surprisingly little for either. I've been coal rolled only once.
Once I was taking the board off the car at a spot in Crescent City, and a passing guy said, "Living the dream!"
That helped me appreciate my life.
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Well, its not extremely hard.
The indicated range is a measure of the battery capacity, and is directly coupled to the BMS estimate of the battery capacity.
The BMS is quite good at estimating the capacity. It can be off from time to time, bit in general its not that bad on this.
( for older cars with possible higher degradation I do not know of there is a ”hide degradation feature” or something like that).
I had my BMS fairly off about one year ago. I was quite sure about the battery capacity
and to check I made a 100-0% drive, which was spot on with my estimate.
(Theres no danger doing a 100-0%, except it should be performed at not too high speed, so it will take some time.
My new S started of very low 95.3kWh (out of 99.4kWh full pack when new) and I was
able to calculate the capacity to 98kWh, plus minus a few 1/10kWh.
After a little usage, the BMS calculated capacity has now Climbed to 97.9-98.0kWh.
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