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Help understanding battery read-out 2017 MX 90D via App

Maxitt

Member
Oct 9, 2021
8
11
New York
Hi everybody,

Been an Tesla fan for a long time and after looking at Tesla's for an equally long time we finally saved up enough to pull the trigger and go forward to buy one. So also a good opportunity to join the club :).

But need some advice on understanding how to read the battery read-out, which the seller provided to me. He had an app for this, which provided a large range of information and the salesperson said the car had about 92% capacity remaining and could drive about 220-300 miles on a full charge . After looking at the data myself I am not sure this is correct so please your opinion on what the real remaining capacity, degradation and real range is.
% charge of the battary pack at moment of measurement was 84%

App data
BMS max discharge: 362 kwh
BMS max charge: 88.5 kwh
Nominal full pack: 72.9 kwh
Nominal remaining: 19,2 kwh
Expected remaining: 37.3kwh
Ideal remaining: 77.8 kwh
To charge complete: 0.40 kwh
Usable: 19.2 kwh
Rated range: 220 miles
Ideal range: 175 miles
Full rated range: 430 miles
Full ideal range: 341 miles
DC-DC efficiency: 90.6%
SOC: 26.3%
SOC expected: 51.2%
SOC min: 84.5%
SOC IU: 83.4%

Cells are all balanced with a range of 4.045 - 4.054 vc, imbalance is 9.15 mV.
Car has been charged 85% AC and 15% DC

Seller calculated the battery capacity by taking the ideal remaining capacity/Tesla reported capacity= 77.8/85.8 kwh). But I think he should have taken the nominal full pack and divide that by the factory capacity (72.9/85.8) which would give a capacity of 85%.
More concerning to me is the rated range of 220 miles and ideal range of 175 miles. The seller told me this is for the current charge of 84%.

I've added the original screenshots for some of the data for those who want to see themselves.

Below is some background info and some more elements I found for the people who want to read a bit more and provide some more insights, which would be really appreciated.

So a little background: It concerns a 2017 MX90D with about 120K miles on it. The car drives fine and is fully loaded with MCU2 (it has Netflix :) ), CCS upgrade and FSD, with HW 3.0 already installed.

Noticable problems:
The is a tremor at high speeds on the highway, but I am thinking this is due to a balancing issue of one of the tires. The right back tire has extreme inner tire wear (2-3 mm inner tire vs 4-5 mm outer tire, all the other tires are fine).
There is also a significant tremor when around 30 mph when in high suspension. Not there when in standard height suspension. Had the Tesla SC look at this, but they said it is not a problem and a replacement could be done for about 2K.
Some "corrosion" at a corner of the Falcon wing and back spoiler.
Creaking of right Falcon wing door when opening and closing, the door is slightly aligned to the back. Not as bad as Optimus Prime from Bjorn (if you ever watched his video's), but still there.

Any help is much appreciated here. Max
 

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Maxitt

Member
Oct 9, 2021
8
11
New York
Just have to add, which I found very confusing:
I did drive it to the Tesla SC to get it checked out, which took about an hour and also checked out the car inside out when I left the dealer. Sure this would have caused some consumption, but am surprised this did not show up on the consumption screen of the car.

According to the computer the consumption since charging was: 33.6 kwh, average consumption 365 Wh/mile on a distance of 92 miles (2x46 mile)
Percentage on screen went from 84% to about 30%. This would mean that 50% battery would only be 62 kwh and not 72.9, unless the test at Tesla Sc and my having a look at it and testing the doors was not taken along by the system and drained about 5 kwh in 2 hours time.
 

Harvey Danger

Member
Mar 2, 2021
365
269
The Pacific Northwest
Maybe just post some pictures of the dashboard (toggling between distance displayed and energy displayed) and center display energy app (with 'average range' and '30 miles' selected).

The numbers provided in the screenshots do appear to come from the car's CAN bus.

But that app does't look like exactly like my "ScanMyTesla" UI so I'm not sure what I'm looking at. If it's not ScanMyTesla then I'm not familiar with how CAN bus data is decoded or reported by that app.

In fact even if it is ScanMyTesla, they may have changed things. The value for SOC in your screenshots is exactly NominalRemaining divided by NominalFullPack. ScanMyTesla used to do this calculation differently (subtracting a buffer from both numbers before performing the division). Not sure what I'm looking at here.

[Just for historical background: Tesla's BMS still puts some numbers on the CAN bus even though the BMS does not actually use them any more. These numbers are still useful but they are "legacy" numbers that may or may not be mean the same thing as what their original data labels implied. ScanMyTesla derives other useful numbers with simple calculations. It reports all the numbers side by side without distinguishing which are observed and which are made-up. These numbers are documented on ScanMyTesla's website. Currently their site links to this spreadsheet which you may find helpful if you want to "go down the rabbit hole" : Scan My Tesla readings ]

Anyway you are correct to focus on NominalFullPack; In the old days I would have said this car supposedly had 82.25 kWh when new , ie 257 rated miles (advertised range) * 320 Wh per rated mi (fixed constant chosen by Tesla and supposedly derived from EPA testing). I'm not sure where you got 85.8.

So if the current value of NominalFullPack shown in your screenshot means what it used to mean, then 72.9/82.25 is 88.6% of its advertised capacity (whether your particular car had a battery that was better or worse than that when shipped is not knowable). 11.4% degradation after 5 years and 120K miles is about what I would expect, neither better nor worse. If NominalFullPack in your screen shot has already had a 4kWh buffer removed, then your degradation is rather better, more like 7% . Maybe a real expert who is up to date on these things can clarify.

As for the shudder, search this site for "shudder" and do some more reading. Yes this can be repaired, no your car is no longer covered by its original 4 year warranty, and so yes it will cost you somewhere around $2k out of pocket. For 2017 ('pre-raven') X's, reports have been positive about the latest fix provided by Tesla. (In previous years this issue was not easily remediated and service centers provided only temporary fixes. Now they seem to have a better solution.)
 
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Maxitt

Member
Oct 9, 2021
8
11
New York
Maybe just post some pictures of the dashboard (toggling between distance displayed and energy displayed) and center display energy app (with 'average range' and '30 miles' selected).

The numbers provided in the screenshots do appear to come from the car's CAN bus.

But that app does't look like exactly like my "ScanMyTesla" UI so I'm not sure what I'm looking at. If it's not ScanMyTesla then I'm not familiar with how CAN bus data is decoded or reported by that app.

In fact even if it is ScanMyTesla, they may have changed things. The value for SOC in your screenshots is exactly NominalRemaining divided by NominalFullPack. ScanMyTesla used to do this calculation differently (subtracting a buffer from both numbers before performing the division). Not sure what I'm looking at here.

[Just for historical background: Tesla's BMS still puts some numbers on the CAN bus even though the BMS does not actually use them any more. These numbers are still useful but they are "legacy" numbers that may or may not be mean the same thing as what their original data labels implied. ScanMyTesla derives other useful numbers with simple calculations. It reports all the numbers side by side without distinguishing which are observed and which are made-up. These numbers are documented on ScanMyTesla's website. Currently their site links to this spreadsheet which you may find helpful if you want to "go down the rabbit hole" : Scan My Tesla readings ]

Anyway you are correct to focus on NominalFullPack; In the old days I would have said this car supposedly had 82.25 kWh when new , ie 257 rated miles (advertised range) * 320 Wh per rated mi (fixed constant chosen by Tesla and supposedly derived from EPA testing). I'm not sure where you got 85.8.

So if the current value of NominalFullPack shown in your screenshot means what it used to mean, then 72.9/82.25 is 88.6% of its advertised capacity (whether your particular car had a battery that was better or worse than that when shipped is not knowable). 11.4% degradation after 5 years and 120K miles is about what I would expect, neither better nor worse. If NominalFullPack in your screen shot has already had a 4kWh buffer removed, then your degradation is rather better, more like 7% . Maybe a real expert who is up to date on these things can clarify.

As for the shudder, search this site for "shudder" and do some more reading. Yes this can be repaired, no your car is no longer covered by its original 4 year warranty, and so yes it will cost you somewhere around $2k out of pocket. For 2017 ('pre-raven') X's, reports have been positive about the latest fix provided by Tesla. (In previous years this issue was not easily remediated and service centers provided only temporary fixes. Now they seem to have a better solution.)
Thanks Harvey, was already worried this was the case. Saw your reply too late unfortunately.

Bought the car already, so will test it the next few days by charging it to near 100% and driving it to single digits and see if the pack is indeed getting the range/consumption which one would expect from a 72.9 kwh or a 77.8 kwh.

What is the better solution by the way? The SC just provided the option for replacing the half shafts and stated this would be a temporary fix only.
 

Harvey Danger

Member
Mar 2, 2021
365
269
The Pacific Northwest
For shudder, first check to confirm you feel the shudder *during acceleration *. If you are experiencing constant vibration at all speeds you may have balancing or alignment issues, as you said. Or you may have a combination of those issues *and* shudder.

If you do experience an alarming vibration shaking the entire car and making a loud sound while performing a max-power acceleration from 20 to 50 mph, you have shudder. Have a service center perform the replacements specified in SB-21-39-001.

Pay close attention. SB-19-39-001 was the previous fix, the name looks similar but the parts are different. Get ..21 not ..19. Review the discussion at News for Model X owners with the dreaded shudder

As for battery health, take the same three pictures as shown below (the fourth picture just shows where to find the control to make the necessary change to the display setting) and post them here. Make sure you take all the pictures at the same time. Don't take them on different days.

Also not sure why you would need a CCS upgrade if the car will stay in NY?
 

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