Model S90D Battery Degradation?

[ahkahn]

Mine still continues to lose range like crazy. Another 3 miles in the last few months. I reached out to Tesla support and they "ran diagnostics" on it, said everything looked fine, but they suggested maybe I take the car in to get looked at. So I just don't see a point in paying $99 or whatever their diagnostic fee is just to tell me the battery is within spec...

They also said that my car is consistent with others in the same age/mileage range....

 

[Peter Lucas]

Mine still continues to lose range like crazy. Another 3 miles in the last few months. I reached out to Tesla support and they "ran diagnostics" on it, said everything looked fine, but they suggested maybe I take the car in to get looked at. So I just don't see a point in paying $99 or whatever their diagnostic fee is just to tell me the battery is within spec...

They also said that my car is consistent with others in the same age/mileage range....

View attachment 501759

Where are you getting the numbers for your chart? The cars display of Rated Range extrapolated to full charge? Actual battery degradation may be greater than implied by the cars display of range.

 

[ahkahn]

Where are you getting the numbers for your chart? The cars display of Rated Range extrapolated to full charge? Actual battery degradation may be greater than implied by the cars display of range.

I use TeslaFi which has monitored my car since practically new. That is a battery report which logs every single charge, and if the charge isn't 100%, it will extrapolate the completed charge to 100%. So if it's a 90% charge (most of the time) it will divide by .9 to get a 100% figure, and then log it.

 

[Peter Lucas]

I use TeslaFi which has monitored my car since practically new. That is a battery report which logs every single charge, and if the charge isn't 100%, it will extrapolate the completed charge to 100%. So if it's a 90% charge (most of the time) it will divide by .9 to get a 100% figure, and then log it.

I have TeslaFi. It repeatedly reports "efficiency" of 65% to 75%.
(If I drive at the rated wh/mi it is 80-85%). The only times I get close to 100% efficiency are downhill trips. TeslaFi's efficiency calculation is a combination of driving efficiency and battery degradation. Because they mistakenly take the cars report of range as honest.

 

[ahkahn]

I have TeslaFi. It repeatedly reports "efficiency" of 65% to 75%.
(If I drive at the rated wh/mi it is 80-85%). The only times I get close to 100% efficiency are downhill trips. TeslaFi's efficiency calculation is a combination of driving efficiency and battery degradation. Because they mistakenly take the cars report of range as honest.

Are you sure you have the correct model that you own set in TeslaFi? My drives are always pretty close to accurate. Something just seems wrong with your car, Peter.

 

[Peter Lucas]

Are you sure you have the correct model that you own set in TeslaFi? My drives are always pretty close to accurate. Something just seems wrong with your car, Peter.

Yes, there is something wrong with my car. It has a degraded battery. The only reason that anyone else should be interested is because: 1) Tesla refuses to acknowledge this, and 2) The cars display of full charge range conceals rather reveals this degradation.

 

[nkohlimd]

Thanks all for your input. Is there a problem with the 90 battery. Planning on trading my 2013 p85 for a 2016 90d this Sat. current car has over 70000 miles and still charges to 283 full charge. What would be the minimum full charge I should accept when picking up the new used car. Seems like a loss if the 90d has less range than my current P85.

 

[ahkahn]

Thanks all for your input. Is there a problem with the 90 battery. Planning on trading my 2013 p85 for a 2016 90d this Sat. current car has over 70000 miles and still charges to 283 full charge. What would be the minimum full charge I should accept when picking up the new used car. Seems like a loss if the 90d has less range than my current P85.

P85 charging to 283? I didn't think they went that high new. If you're getting that on a P85, you'll never see a 90D used get that high.

 

[nkohlimd]

That's what I'm worried about - makes me think if I should even trade it in. Thanks for the advice.

 

[Peter Lucas]

Thanks all for your input. Is there a problem with the 90 battery. Planning on trading my 2013 p85 for a 2016 90d this Sat. current car has over 70000 miles and still charges to 283 full charge. What would be the minimum full charge I should accept when picking up the new used car. Seems like a loss if the 90d has less range than my current P85.

The problem is that the cars display of full charge range is not reliable. Either as an estimation of real range or as an indicator of battery degradation.
To determine battery condition/capacity you need to take the car on a long trip, driving modestly, and note the change in SOC. (The longer the trip, the more accurate the result will be) For example, if you drive the car from 80% SOC to 30%, and that got you 100 miles, then the full charge range is 100 miles divided by (80% minus 30%). 80% minus 30% is 50%. 50% is 0.5. So 100 miles divided by 0.5 is 200 miles. The car in that example would have a 200 mile full charge range. When new it was (about) 285 miles. Now you get to decide on how satisfied you are with that amount of battery degradation. And at what price.

 

[nkohlimd]

Thank you...always learn alot from these forums....

 

[supratachophobia]

The problem is that the cars display of full charge range is not reliable. Either as an estimation of real range or as an indicator of battery degradation.
To determine battery condition/capacity you need to take the car on a long trip, driving modestly, and note the change in SOC. (The longer the trip, the more accurate the result will be) For example, if you drive the car from 80% SOC to 30%, and that got you 100 miles, then the full charge range is 100 miles divided by (80% minus 30%). 80% minus 30% is 50%. 50% is 0.5. So 100 miles divided by 0.5 is 200 miles. The car in that example would have a 200 mile full charge range. When new it was (about) 285 miles. Now you get to decide on how satisfied you are with that amount of battery degradation. And at what price.

Actually, it's extremely accurate if you know the simple fact that Tesla is including the 4kw bottom end buffer in their full charge calculation. 0% on the dash means you've reached that 4kwh buffer. When they EPA tested, 0% was really 0%.

 

[ran349]

That's what I'm worried about - makes me think if I should even trade it in. Thanks for the advice.

If you are getting 283 miles, it's almost a certainty that you are displaying ideal miles, not rated miles.

 

[Peter Lucas]

Is there a good reason why no one uses the ‘Total energy’ data from the Trip menu? Isn’t that what we are supposed to compare in order to find true degradation? How much kWh the battery originally had to what capacity it is capable of now.

According to Jason-
“90D/P90D – ~85.8 kWh total capacity, 81.8 kWh usable“

So if I charged to ~80% and drove to ~30% (using 50% of the battery), assuming I had a brand new perfect 90 battery pack, ~40.9 kWh would display as Total Energy for that Trip.

Now try this on your 90D P90D

You are correct. I have been promoting this analysis for some time. But many owners don't get it. When you use the "khw used" values with change of SOC you can calculate the total usable battery capacity of your car. You need to use a significant portion of the battery to get reliable battery capacity. I have found that my 90D has a usable battery capacity of 72-73 kwh. That correlates to my greatly reduced range. The thing that is really disturbing is that the cars display of full charge range is almost like new. If I relied on the cars display of range as an indication of battery degradation, as most people do, I would have the wrong idea that my battery is just fine. Bottom line is that the cars display of full charge range conceals rather than reveals battery degradation.

 

[Peter Lucas]

Update: now at 43.5K miles
Range at 100% is 271-273
The key change is that max supercharge rate is now 93kW, consistent 8x at 5 different superchargers in April.

We are returning the car to Tesla under the Resale Value Guarantee in June. We plan to get a 370 mile rated range "Raven" Model S in August or September.

What are the details of Tesla's "Resale Value Guarantee" ?

 

[Peter Lucas]

Update: After the latest set of firmware updates my Model S's range dropped slightly. It's now showing 259 miles of range at 90%, implying 288 miles range at 100%, now at 17500 miles. I'm thinking this was impacted by the BMS changes Tesla introduced to S/X after the latest fire in a China parking ramp.

Have other 90D owners noticed a sudden drop with the latest software updates?

My early 2016 S 90D has a usable battery capacity of 72-73 kwh. And the reduced range that goes with that. Weird thing is that the cars display of full charge range is only down a little bit. (275 from 285 when new). The cars display of full charge range is NOT a reliable indicator of battery degradation.

 

[Peter Lucas]

Waiting for the hate mail...

I think the Tesla packs are really poor. My 2016 90d version 1 pack:
1. 80% charge 203 miles, real world miles 157 driving really slow, 327 watts/mi. (under delivers)
2. My 2019 egolf has a range of 125 miles, I get 150 real world miles out of it typically. (35.4 kw pack) (Over delivers)

My $100k Tesla(80% charge) and the $12k eGolf, deliver almost the same amount of real world miles. Granted they are totally different cars.

Agree. The battery in my early 2016 90D has only about 72-73 kwh usable. And that has been since the car was 6 months old. Usual range is about 200 miles (displays 275). Can get 220 miles if drive like an old lady.

 

[supratachophobia]

You are correct. I have been promoting this analysis for some time. But many owners don't get it. When you use the "khw used" values with change of SOC you can calculate the total usable battery capacity of your car. You need to use a significant portion of the battery to get reliable battery capacity. I have found that my 90D has a usable battery capacity of 72-73 kwh. That correlates to my greatly reduced range. The thing that is really disturbing is that the cars display of full charge range is almost like new. If I relied on the cars display of range as an indication of battery degradation, as most people do, I would have the wrong idea that my battery is just fine. Bottom line is that the cars display of full charge range conceals rather than reveals battery degradation.

This is because at full charge, the car includes the bottom 4kw brick protection in it's range calc. At least than 20%, it takes that 4kw away from the calc. 0 on the dash means 4kw left.

 

[Peter Lucas]

This is because at full charge, the car includes the bottom 4kw brick protection in it's range calc. At least than 20%, it takes that 4kw away from the calc. 0 on the dash means 4kw left.

A healthy "90" kwh battery should have about 82-84 kwh of usable energy due to top end charging limits and low voltage cut-off. So a "90" kwh battery that is only providing 72-73 kwh of usable energy is either defective, degraded, or has a BMS which is not operating normally.

 

[mrElbe]

A aside Note. The new warranties effective as of Jan. 29 2020 consider a battery to be within specs at or over 70% capacity. There is no mention how "capacity" is calculated.