2017 MS 75D - Battery Pack degrading much faster than previous generations

[n8vision]

I've had my car just over 1 year (bought in Nov 2017). It was a service loaner with 5000 miles on it and displayed 252 miles of rated range @ 100% back then. That's 97.3% of original capacity -- acceptable.

Fast forward just over a year, now 30k miles total, and I now get 236 miles at 100%. If you believe rated range is based on a constant calc, not driving style, that's 91.1% of original capacity, and it's continuing to trend down a little every few months. I don't supercharge often, or let it get below 20% often (these events happen maybe 10-20 times a year).

The service center says rated range adapts to driving behavior. I don't believe them, but is this really true? Has this changed in later generations? Or is it still based on a wet Wh/M for the later generations of car and the SC is deflecting my valid concern.

When I look at data from previous generations of MS (60, 85, etc), everyone seems to be in Lala land about their battery - stating they've only seen 3-7% in hundreds of thousands of miles and years later. What's up with the 75D? If my trend continues I'd be tempted to sell the car before it gets worse, and get a M3. I doubt Tesla will care unless my battery actually fails. Perhaps I should intentionally run it into the ground within warranty to get a replacement? It's a weird dynamic because I want to love my car, but I don't love 10% degradation per year.

Curious to hear if other owners have similar concerns, particularly those with 75 / 75D / 90Ds.

 

[ewoodrick]

The odds are that your battery isn't degraded, just the way that you are looking at it.
Slow charge to 100% and run down to 20% a time or two and see what it says.

 

[BerTX]

I've had my car just over 1 year (bought in Nov 2017). It was a service loaner with 5000 miles on it and displayed 252 miles of rated range @ 100% back then. That's 97.3% of original capacity -- acceptable.

Fast forward just over a year, now 30k miles total, and I now get 236 miles at 100%. If you believe rated range is based on a constant calc, not driving style, that's 91.1% of original capacity, and it's continuing to trend down a little every few months. I don't supercharge often, or let it get below 20% often (these events happen maybe 10-20 times a year).

The service center says rated range adapts to driving behavior. I don't believe them, but is this really true? Has this changed in later generations? Or is it still based on a wet Wh/M for the later generations of car and the SC is deflecting my valid concern.

When I look at data from previous generations of MS (60, 85, etc), everyone seems to be in Lala land about their battery - stating they've only seen 3-7% in hundreds of thousands of miles and years later. What's up with the 75D? If my trend continues I'd be tempted to sell the car before it gets worse, and get a M3. I doubt Tesla will care unless my battery actually fails. Perhaps I should intentionally run it into the ground within warranty to get a replacement? It's a weird dynamic because I want to love my car, but I don't love 10% degradation per year.

Curious to hear if other owners have similar concerns, particularly those with 75 / 75D / 90Ds.

There are a lot of factors here. Your car was a loaner, so it is questionable as to how much care was taken in the battery maintenance as far as charging is concerned. It is possible they just set it to 100% every night to be ready for the next day. On weekends, it may have sat that way.

Past data shows that the batteries degrade more early in their life then level off. Yours has degraded more than my 2016 in less time. My unsubstantiated view is that the car loses some range in my admittedly mild winter, then recovers some, but not all, in the summer. Remember that just looking at Rated Range to assess battery is very inaccurate (definitely not within the "91.1%" accuracy level you use). It shows trends, not true degradation, and reports inaccuracies in the measurement of battery status as well as degradation, so it is hard to tell the difference.

As to the SC telling you the RR is driver related, that is apparently a corporate misinformation that is Tesla's policy to spread. I thought it was just misinformed personnel, but it is too pervasive an occurrence. File it under "Don't automatically believe what Tesla tells you" and move on.

As far as intentionally doing things to cause battery issues, you might want to read the warranty, which specifically addresses this, and remember that Tesla is watching everything you do. And especially don't talk about doing it on a public forum.

 

[ucmndd]

It’s not unheard of with the 75s. I started a thread on this topic a year ago maybe. My Dec 2016 75 with 70,000 miles was on a similar curve, but did level off substantially in the last year. I’m now at about the same 9-10% degradation you are as reported by rated range.

 

[n8vision]

It’s not unheard of with the 75s. I started a thread on this topic a year ago maybe. My Dec 2016 75 with 70,000 miles was on a similar curve, but did level off substantially in the last year. I’m now at about the same 9-10% degradation you are as reported by rated range.

Thanks for this. Gives me some hope. That said, two owners (S75, S90D) have reported 12-14% degradation in another thread I started.

 

[n8vision]

The odds are that your battery isn't degraded, just the way that you are looking at it.
Slow charge to 100% and run down to 20% a time or two and see what it says.

I will do this and report back, to dispel those who think it's BMS drift. I highly doubt the reading will change. If it doesn't, what would be the suggested next steps?

 

[MP3Mike]

I will do this and report back, to dispel those who think it's BMS drift. I highly doubt the reading will change. If it doesn't, what would be the suggested next steps?

Given that there is no gradual capacity degradation warranty for the battery packs on the S&X there is nothing to do unless your battery fails or has a sudden capacity loss.

 

[ucmndd]

I will do this and report back, to dispel those who think it's BMS drift. I highly doubt the reading will change. If it doesn't, what would be the suggested next steps?

I've done this multiple times to address the common response that this is some sort of cell/battery balancing issue. It doesn't work. My rated range has gone one way and one way only - down.

 

[shred86]

I'd be curious what your battery is reporting in terms of actual capacity in kWh. I think there's too many unknowns with using rated range as a way to measure battery degradation. You can get the actual capacity in kWh with an app like TM-Spy, but it also requires an OBD2 adapter and bluetooth module. You can find more information on TM-Spy in this thread if you're interested. It's extremely easy to setup - I just did it a couple weeks ago when my adapter cable and bluetooth module came in.

Here's an example from my car (2015 85D with ~44k miles): 76.2 kWh actual capacity remaining.

The only thing I don't know if that number is showing total capacity or usable. I suspect total capacity. These are the approximate numbers for a new 85D: ~81.5 kWh total capacity, ~77.5 kWh usable. The 90D: ~85.8 kWh total capacity, 81.8 kWh usable.

 

[ThisIsTrue]

Just for another days point: I also have a 75D, from October 2016. I now have 56K miles, from many road trips (=lots of supercharging). I also occasionally slow charge to 100%, and rarely get much below 10%. My recent full charge showed 250 miles. As always, your mileage may vary....

 

[N..8]

I'd be curious what your battery is reporting in terms of actual capacity in kWh. I think there's too many unknowns with using rated range as a way to measure battery degradation. You can get the actual capacity in kWh with an app like TM-Spy, but it also requires an OBD2 adapter and bluetooth module. You can find more information on TM-Spy in this thread if you're interested. It's extremely easy to setup - I just did it a couple weeks ago when my adapter cable and bluetooth module came in.

Here's an example from my car (2015 85D with ~44k miles): 76.2 kWh actual capacity remaining.

The only thing I don't know if that number is showing total capacity or usable. I suspect total capacity. These are the approximate numbers for a new 85D: ~81.5 kWh total capacity, ~77.5 kWh usable. The 90D: ~85.8 kWh total capacity, 81.8 kWh usable.

Shred, TM-spy is showing total capacity, there is another thread on here that we are showing that. I had my S75 down to 1 mile indicated Rated miles and had TM-spy showing 4.3kWh left.

 

[hacer]

It’s not unheard of with the 75s. I started a thread on this topic a year ago maybe. My Dec 2016 75 with 70,000 miles was on a similar curve, but did level off substantially in the last year. I’m now at about the same 9-10% degradation you are as reported by rated range.

That is hopeful. My May (build) 2016 S75D with 31,700 miles is down to 232 miles rated range at 100% and it's had a very linear decent (vs mileage) the whole time. Theoretically (delivered as a 70D) it started at 259 miles range, so 10% degradation so far. I got one of the very first face-lift cars off the line with the new 75kWh battery. I think this was an early chemistry also used in the early 90D's and was not used for very long before they made further chemistry changes.

I have not abused my battery, it's normally charged to about 88% and rarely ever discharged below 20%. I have done quite a few road trips (my daily commute is less than 1 mile each way!) and probably have supercharged a little over 100 times. I'm really hoping the linear degradation will level off eventually.

 

[Electric700]

What are you charging to normally? I have mine (a 2014 85) set to a maximum of about 80%. I read this level might be better for the battery than 90%. I also generally charge it when it gets just below 40%. For trips I may charge to about 90% and go to 10 - 20%. 1 - 2 times a year I charge to 100%, but then I drive it immediately after the charge completes. I'm also at 264 miles for 100% versus 265 when new.

 

[shred86]

Here’s an example of a 2016 Model S 70D with 29k miles that I pulled the CAN bus data from:

100% charge advertised miles (new): 240
100% charge rated miles: 217

217/240 = 90.4%

If I’m just using rated ranges to try to estimate battery degradation (which I don’t really recommend), this would suggest this vehicle has a 9.6% degradation in battery capacity.

New kWh: 70 (assuming software limits exactly at 70, since it’s actually a 75 kWh pack)
Current kWh: 67.3

67.3/70 = 96.1%

I have no idea how the estimated range works, but I’d imagine it does take some factors into account over time and will adjust based on whatever algorithm Tesla is using. We’ve also seen users report different estimated ranges after updates, which I suspect is from an update to that algorithm.

Side note:This vehicle was showing the displayed percentage being ~3% higher than the actual state of charge (coming from the CAN bus). Normally, the actual state of charge is ~4% higher than the displayed percentage, so I’d suspect the vehicle would actually shut down before reaching 0% indicated. This would be an example of where letting the battery get to a low SOC then charge up to 100%, repeated a few times, might help resync the displayed battery percentage.

Bottom line, I probably wouldn’t worry too much unless you see a sudden drop in displayed range or abnormal battery behavior. If you really want to know the degradation, you would have to measure the total capacity when it’s new and compare it against current capacity.

 

[Drlev]

I’m going to chime in here too and hope folks can provide some context. My December 2017 75D now has just about 20,000 miles and my rated range is down to 243 miles. This seems substantial given my mileage. A further dive into the data shows my max battery capacity at this point is 69.4 kWh. It’s the steady decline that concerns me most. I’ve done a modest amount of supercharging during about 5 road trips and charge to 80% every night when the weather is warm and 90% during the winter.

 

[N..8]

Drlev, I also have a Dec 2017 S75 with RWD. I have 13.5k mileage and my pack is sitting at 70.8 kWh. I'm sure I will drop to what you have in the next few k's. On occasion I've seen my pack show 70.1 then after I charge it goes back to 70.8 so it's ready to drop to the lower level soon.

 

[BigD0g]

I’m going to chime in here too and hope folks can provide some context. My December 2017 75D now has just about 20,000 miles and my rated range is down to 243 miles. This seems substantial given my mileage. A further dive into the data shows my max battery capacity at this point is 69.4 kWh. It’s the steady decline that concerns me most. I’ve done a modest amount of supercharging during about 5 road trips and charge to 80% every night when the weather is warm and 90% during the winter.

Keep in mind, your car did not start at 75 kW, i'd hazard a bet almost nobody's has, most of us got cars with between 70 - 73 kW battery's when brand new @wk057 has a large thread on this issue and the Tesla untruths about battery capacity. Only the 100's are at least 100 or better batteries when delivered, this is a fact.

 

[Drlev]

Drlev, I also have a Dec 2017 S75 with RWD. I have 13.5k mileage and my pack is sitting at 70.8 kWh. I'm sure I will drop to what you have in the next few k's. On occasion I've seen my pack show 70.1 then after I charge it goes back to 70.8 so it's ready to drop to the lower level soon.

And now after driving this morning it’s at 68.7 kWh.

 

[shred86]

Keep in mind, your car did not start at 75 kW, i'd hazard a bet almost nobody's has, most of us got cars with between 70 - 73 kW battery's when brand new @wk057 has a large thread on this issue and the Tesla untruths about battery capacity. Only the 100's are at least 100 or better batteries when delivered, this is a fact.

I’m pretty sure he’s measuring total capacity, which the 75/75D is supposedly 75 kWh total, 72.6 kWh usable, according to the findings from wk057. TM-Spy shows total capacity.

And now after driving this morning it’s at 68.7 kWh.

It will increase as the battery temperature increases, to a certain point. I’ve also noticed mine increase from 75.5 to 76.2.

 

[shred86]

I’m going to chime in here too and hope folks can provide some context. My December 2017 75D now has just about 20,000 miles and my rated range is down to 243 miles. This seems substantial given my mileage. A further dive into the data shows my max battery capacity at this point is 69.4 kWh. It’s the steady decline that concerns me most. I’ve done a modest amount of supercharging during about 5 road trips and charge to 80% every night when the weather is warm and 90% during the winter.

I’m sure you already know this but just remember the biggest drop in battery degradation usually happens early on then it starts to slow down.