TeslaFi - Battery Degradation Reports (upload your data)

[gilscales]

While I did wait quite a while to get Teslafi, I noticed that when new I could get to 313 and even 314 once or twice when charging to 100%, at 18K to 19K miles it was down to 310, now from there you can see the trend is substantial down from the time the software update adjusted to the new calculations of 325 range (new), I showed 321 when the update was applied but have been seeing a more rapid decline since then

 

[Electroman]

i would guess the buffer should be more than 1.4 kWh you indicate.. more like 3.5+ kWh

 

[Sparky4life]

i would guess the buffer should be more than 1.4 kWh you indicate.. more like 3.5+ kWh

Could be, we know the total capacity based on the number of cells, but we don't really know the usable capacity since that is in software and could even change with a firmware update. To your point, I have also seen 74kWh usable quoted, which means (assuming no physical degradation):

if you average 239 Wh/mi you will get 310 miles on a full charge, and
if you average 228 Wh/mi you will get 325 miles on a full charge

It's hard to tell from the dashed 'rated' line on the energy display whether the constant is 239 or 242 (which it would be if the usable capacity was 75kWh).

 

[Sparky4life]

Sorry, the 'rated' line is solid, the dashed line is your current average.

 

[AlanSubie4Life]

if you average 239 Wh/mi you will get 310 miles on a full charge, and
if you average 228 Wh/mi you will get 325 miles on a full charge

While this is true (if your assumptions of available energy are true - remember the EPA test measured 78kWh available but of course some of that is the reserve):

These 239Wh/mi and 228Wh/mi numbers you quote may not be what the in-car display shows. The in-car display is just a meter and does not necessarily reflect actual consumption.

It’s confusing, and hard to know the actual numbers, for sure. But so far available evidence suggests 78kWh available from a new battery (this is very likely correct since it was an EPA measurement), and probably 76kWh or so are used by “0 miles” (no one knows exactly what the number is). And the meter in the car for such a discharge might show 73kWh used.

The Wh/rmi constant (using the in-car display) for the LR RWD is about 230Wh/rmi. For the AWD it is 230Wh/rmi (I have not checked it on the new firmware but I would think it has not changed).

 

[MaryAnning3]

How many of your total miles are from Supercharging? Does that seem to correlate at all with range?

 

[MaryAnning3]

Ah, okay I see the confusion. The car used to turn on and unfold the mirrors (like S/X) when you walked up before you ever pulled the door handle. That feature was called Walk Up Unlock (basically the opposite of Walk Away Lock). That feature/option is no longer present. Now to get the car to "turn on" you have to pull the door handle.

Thanks for that. I think I had walk up unlock for a week or two and then it went away. I thought maybe it was my imagination. Good choice to get rid of it. I like the way it is now.

 

[bijan]

Mine's in km., but about 28k miles and 6% degradation it seems. Was about 0% degradation at beginning of June and 22k miles.

 

[Thunder7ga]

All was going fine until about mid-April 2019...not sure what changed. Still doing OK, but the quick down spike is concerning.

Battery Report 8-11-2019

• Thunder7ga
• Aug 11, 2019

Battery Report 2

• Thunder7ga
• Aug 11, 2019

 

[Zoomit]

but the quick down spike is concerning.

It’s the slow declines that reflect the physics of Li-ion battery degradation. Quick spikes are artifacts of the prediction algorithm or changes to it. But yes, it is concerning that the code is not producing realistic results.

 

[rob.kibler]

I didn't see the jump from 310 miles to 325 miles, but I saw some improvement. I have charged to 100% maybe once. And I have let the charge get below 10 % maybe once. Odometer is at 20,067 miles.

 

[bijan]

Mine again in miles this time. Starting to get a little worried down to 290 from 310 originally. All in the past 2 months or so. Going to see what happens when the weather cools back down.

 

[JES2]

I'm down to 296 after one year. No supercharging. I'm in Texas, so it might be the heat for the last few months. I normally charge to 80% once the battery falls below 40%.

 

[EV-Tech Exp]

Some interesting trends emerging here. Anybody know if this TeslaFi data can be exported for us to start building up a database to do some analysis?

 

[bijan]

Some interesting trends emerging here. Anybody know if this TeslaFi data can be exported for us to start building up a database to do some analysis?

TeslaFi gives all the data points that are used in a table below the graph. It should be easy to just copy paste that into Excel.

Edit: here are the columns in the table:
Date, Charge %, Battery Range, Estimated Range At 100%, Odometer, Firmware Version, Outside Temperature

 

[TJFair]

I was very happy with my battery performance (2017 S100D) through 65K miles, then I saw a steep drop. I'm at 10% total loss now, and it's affecting my ability to take the car to rural destinations. Tesla says everything is normal, of course. A big selling point for me was the unlimited 8-year battery warranty and what my sales consultant said was a "replacement battery if you experience 10% degradation". Should have read the fine print (That's only for Model 3 batteries. Sorry!). I'm quickly moving from Raving Fan to Unhappy Camper. Too bad the range in the new Porsche Taycan is only 220 miles...

 

[RobC]

Doesnt the TeslaFi data just use the estimated range the car is providing? If so this is hardly scientific since we know how inaccurate the estimated range. It changes wildly based on numerous different variables and can even be affected by changes in the way it is calculated.

 

[bijan]

View attachment 452707
A big selling point for me was the unlimited 8-year battery warranty and what my sales consultant said was a "replacement battery if you experience 10% degradation". Should have read the fine print (That's only for Model 3 batteries. Sorry!).

It's 30% degradation guarantee for the model 3. As in they'll fix it if it drops below 70% capacity. But it's not 8 years unlimited. I think it's only 120k miles. I'm at 8% and 27k miles on my model 3.

 

[pdx_m3s]

Is it possible to estimate degradation without charging to 100%? E.g. dividing rated miles displayed by battery percentage displayed?

 

[scottf200]

Is it possible to estimate degradation without charging to 100%? E.g. dividing rated miles displayed by battery percentage displayed?

This is what TeslaFI.COM display is doing.

Example of my cut-n-paste of my date from it and then a re-calculated column.