Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

[AlanSubie4Life]

Hmm, I have a 2020 stealth with 19s. Before the update I had 310 and now it's 299 ish. Are you basically saying that now the estimated range is taking the tires into account since they are less efficient?

Yes, but additionally it MAY be that you have more energy. The way to check is to switch your wheel configuration to 18” temporarily and see what your estimated 100% is (it will be around 314 for you - which is actually closer to 317 in the old units of rated miles - the new miles with 18” contain slightly more energy than the old miles (248Wh vs 245Wh). So you’ve probably been gifted 7 miles of range for Christmas. Merry Christmas!

 

[rtshefe]

Hmm, I have a 2020 stealth with 19s. Before the update I had 310 and now it's 299 ish. Are you basically saying that now the estimated range is taking the tires into account since they are less efficient?

yes...thats exactly the case.

My energy graph shows the rated range line in different locations based on the wheels I chose in the setup. So now the p3d with 20" wheels is rated at around 293-294 miles...19 inches are around 299 rated miles and I think the aero 18 are 310ish still (actually showed 313 when I switched it on my car)

 

[12jdlovins]

Yes, but additionally it MAY be that you have more energy. The way to check is to switch your wheel configuration to 18” temporarily and see what your estimated 100% is (it will be around 314 for you - which is actually closer to 317 in the old units of rated miles - the new miles with 18” contain slightly more energy than the old miles (248Wh vs 245Wh). So you’ve probably been gifted 7 miles of range for Christmas. Merry Christmas!

(I have the heat on so I think the miles are actually off by 1-2 since between pictures I lost a mile.)
Okay so I just went into my car and switched it to 18 aeros and this is what I got.
234 miles at 75% charge.

So that is 312 at 100%.

And then 19s is..
224 miles at at 75%

Which is 299.

 

[AlanSubie4Life]

(I have the heat on so I think the miles are actually off by 1-2 since between pictures I lost a mile.)
Okay so I just went into my car and switched it to 18 aeros and this is what I got.
234 miles at 75% charge.
View attachment 495215

So that is 312 at 100%.

And then 19s is..
224 miles at at 75%
View attachment 495219

Which is 299.

And most relevant: according to the energy consumption screen you have 58kWh available at this 75% charge which extrapolates to 77.2kWh. Previously this extrapolated to 76kWh for your car. There is some margin for error on this number - other pictures I have seen suggest closer to 77.5kWh (though it depends on the car of course), but it depends on the accuracy of your reported 75% number (e.g. is it closer to 74.5% or closer to 75.5%) - makes a difference of up to about 3 miles or 0.7kWh.

In any case you have more range - your charge constant with 18” wheels is now 58kWh/234rmi = 248Wh/rmi, and previously this value was 245Wh/rmi.

* instead of more range, Tesla may have also just inflated the kWh (made them contain less actual energy) - which would mean no change. But it’s super hard to establish that, so I am assuming they did not change that.

 

[12jdlovins]

And most relevant: according to the energy consumption screen you have 58kWh available at this 75% charge which extrapolates to 77.2kWh. Previously this extrapolated to 76kWh for your car. There is some margin for error on this number - other pictures I have seen suggest closer to 77.5kWh (though it depends on the car of course), but it depends on the accuracy of your reported 75% number (e.g. is it closer to 74.5% or closer to 75.5%) - makes a difference of up to about 3 miles or 0.7kWh.

I did have tesla do a battery health check on my car yesterday since i was trying to figure out what happened and she said my car is at 219 Ah from the initial 230 with just a little over 1k miles on the car which is apparently within 0.3% of the average, not sure in what direction though.

Could you please show the calculations for how you got 77.2kWh? I would love to understand this stuff more.

 

[AlanSubie4Life]

she said my car is at 219 Ah from the initial 230 with just a little over 1k miles

I’m not sure what that means but I tend to not believe it. (219Ah*350V = 76.6kWh but that’s a bad way to measure this...and I don’t believe the 230Ah number in this context)

The calculation is the standard formula for the energy screen:

Charge Const = Recent Efficiency * Projected Range / Rated Miles Remaining


Recent efficiency * Projected range just tells you how much energy is left in your battery according to the BMS. It’s the same as using a CAN bus reader. You can also divide that number by your current SoC % to get an estimate of your full battery capacity. You will see this number reduce over time.

I have a post explaining this elsewhere but I need to update it with the new info which is why I am not linking to it.

312 miles is 316 miles in the old system so you’ve been gifted roughly 6-7 miles.

Except for the Energy Trip page predictions, it does not matter which wheels you select. You should select the ones that are on your car in most cases...unless you are doing something like running PS4S on 18”, in which case you should probably select 19” or 20” for a better match to reality and better trip arrival % predictions. That trip predictor uses the wheel configuration (which affects rolling resistance and aero) internally to adjust its estimates.

It’ll be cool if Tesla can provide us the ability to construct our own wheel model at some point since some people have a lot of frustrations when they are running really inefficient wheels.

 

[12jdlovins]

I’m not sure what that means but I tend to not believe it.

The calculation is the standard formula for the energy screen:

Charge Const = Recent Efficiency * Projected Range / Rated Miles Remaining


Recent efficiency * Projected range just tells you how much energy is left in your battery according to the BMS. It’s the same as using a CAN bus reader. You can also divide that number by your current SoC % to get an estimate of your full battery capacity. You will see this number reduce over time.

I have a post explaining this elsewhere but I need to update it with the new info which is why I am not linking to it.

312 miles is 316 miles in the old system so you’ve been gifted roughly 6-7 miles.

Thank you very much for the information, I definitely have a better understanding and will have to dive deeper to really understand it more. it's just funny how losing 10 miles is actually an increase hah. I can finally stop freaking out about it.

 

[QS01]

Separately, the constant used is now dependent on wheel selection, so selecting different wheels on 2020 Dual Motors seems to change the displayed range. (It has never behaved this way before, though the wheel selection DID affect the Energy Trip estimates and projections.). So now all is consistent. If you select 18” wheels it appears that 100% range will exceed 310 rated miles (about 314).

this seems to support what I’m seeing in my P3D- as after the update I’m seeing 282 mile estimated range at 90% charge.

 

[AlanSubie4Life]

282 mile estimated range at 90% charge.

Good to hear. This is equivalent to 282rmi (new) * (248Wh/rmi (new)) / 245Wh/rmi (old)) = 285.5 rmi (old)

So about 286 rated miles under the old system.

 

[QS01]

Good to hear. This is equivalent to 282rmi (new) * (248Wh/rmi (new)) / 245Wh/rmi (old)) = 285.5 rmi (old)

So about 286 rated miles under the old system.

Prior to the update I was getting 279 on a 90% charge. 310 at 100%. (My M3 is a month old)

 

[AlanSubie4Life]

310 at 100%. (My M3 is a month old)

So now you have the equivalent of:

282rmi (new) /0.9 * 248/245 = 317 rmi (old)

So 7 more rated miles (1.7kWh) when viewed in the old system.

 

[Ryanide]

So if I only drive 20-30 miles a day, is it fine to charge every 4th or 5th day? Is there any reason to charge it every night if I don’t plan on needing the extended range?

 

[pdx_m3s]

So if I only drive 20-30 miles a day, is it fine to charge every 4th or 5th day? Is there any reason to charge it every night if I don’t plan on needing the extended range?

I typed out a long response to this question and then realized it’s pointless and will just derail the thread. This same question gets asked daily on this forum and always ends up in roundabout arguments. I’m not taking the bait. Please search.

 

[AlanSubie4Life]

I typed out a long response to this question and then realized it’s pointless and will just derail the thread.

That is funny. I did exactly the same thing.

 

[insaneoctane]

Anyone with OBDII / ScanMyTesla access care to share their "nominal full pack" readings? Mine is reading 70.5 kWh. I just got the reader, so I don't have previous readings, but my API logged range vs SOC has dropped more in the last few months / firmwares than it did in the previous year+ and 30K miles!

 

[AlanSubie4Life]

70.5 kWh.

If I recall correctly you have an LR RWD. If so you should see a projected 100% of about 301 rated miles. Is that right?

You should be able to reasonably accurately compare with others using the rated miles. SMT is not really needed for that alone (though it provides a bunch of other cool info), as long as you are careful to compare the same vehicle type; e.g. AWD miles can’t be compared to LR RWD.

You had at least 76kWh available originally when the car was new I think (though for LR RWD it is slightly less clear what was originally available, due to the change from 310 to 325 which made more capacity visible). Might have been as much as 77kWh even.

Anyway this result is a bit on the low side (though normal) and in Southern California temp would only be a very small factor unless you live in a frost-prone area.

What does SMT say is the max voltage difference? And did your weird exponentially decaying rated miles after parking issue go away? Would be interesting to check this imbalance over time if that issue is still happening. SMT might be good for that.

 

[insaneoctane]

If I recall correctly you have an LR RWD. If so you should see a projected 100% of about 301 rated miles. Is that right?

You should be able to reasonably accurately compare with others using the rated miles. SMT is not really needed for that alone (though it provides a bunch of other cool info), as long as you are careful to compare the same vehicle type; e.g. AWD miles can’t be compared to LR RWD.

You had at least 76kWh available originally when the car was new I think (though for LR RWD it is slightly less clear what was originally available, due to the change from 310 to 325 which made more capacity visible). Might have been as much as 77kWh even.

Anyway this result is a bit on the low side (though normal) and in Southern California temp would only be a very small factor unless you live in a frost-prone area.

What does SMT say is the max voltage difference? And did your weird exponentially decaying rated miles after parking issue go away? Would be interesting to check this imbalance over time if that issue is still happening. SMT might be good for that.

It was up to 71.5 this morning. Strange that it moves around so much on me. Even stranger is that my nominal full pack capacity INCREASES as my car sits in the parking lot and loses 12 miles of range (it went from 71.5 when I parked to 71.7 one hour later after losing the 12 miles of range this morning)!! Check out my other post here for more info...…

 

[golfleep]

Anyone with OBDII / ScanMyTesla access care to share their "nominal full pack" readings? Mine is reading 70.5 kWh. I just got the reader, so I don't have previous readings, but my API logged range vs SOC has dropped more in the last few months / firmwares than it did in the previous year+ and 30K miles!

I have a LR AWD built in 9/19, and have had seen my rated miles drop pretty steadily since getting the car, and am currently sitting around 295 miles of rated range at 100%, with 4000 miles on the odometer. To try and better understand things, I started tracking nominal full pack with Scan My Tesla at the beginning of December. I had 74 kWh at the beginning of December with 3000 miles on the odometer. Today, with 4000 miles on the odometer, I have 72.8 kWh. The decline in my rated miles at 100% and nominal full pack values correlate very strongly when graphed out vs. time or mileage, and it seems likely that the two are calculated in a similar manner. Extrapolating the trendline for the nominal full pack curve backwards to when the car was purchased gives a nominal full pack of 76 kWh.

I live in the San Francisco Bay Area, and the car the garaged at night, so my max temp swings are about 50 to 80 degrees at most, so temps really aren't much of a factor. I'm willing to see how things fare over time, but I'm pretty sure my battery is going to be one of those that makes everyone else's batteries look good. It seems like a lot of change for such a short period of time (4 months, 4000 miles).

I have seen nominal full pack values on you tube (mostly on OBDII harness installation videos) range from 68-77 for LR Model 3's

 

[AlanSubie4Life]

It was up to 71.5 this morning. Strange that it moves around so much on me. Even stranger is that my nominal full pack capacity INCREASES as my car sits in the parking lot and loses 12 miles of range (it went from 71.5 when I parked to 71.7 one hour later after losing the 12 miles of range this morning)!! Check out my other post here for more info...…

You've definitely got a strange one. So at 71.7kWh it must look like 306 rated miles projected at a full charge using the app slider or whatever? I posted in your other thread about other things to plot. Seems like the right place to take up that discussion.

 

[KenC]

I have a LR AWD built in 9/19, and have had seen my rated miles drop pretty steadily since getting the car, and am currently sitting around 295 miles of rated range at 100%, with 4000 miles on the odometer. To try and better understand things, I started tracking nominal full pack with Scan My Tesla at the beginning of December. I had 74 kWh at the beginning of December with 3000 miles on the odometer. Today, with 4000 miles on the odometer, I have 72.8 kWh. The decline in my rated miles at 100% and nominal full pack values correlate very strongly when graphed out vs. time or mileage, and it seems likely that the two are calculated in a similar manner. Extrapolating the trendline for the nominal full pack curve backwards to when the car was purchased gives a nominal full pack of 76 kWh.

I live in the San Francisco Bay Area, and the car the garaged at night, so my max temp swings are about 50 to 80 degrees at most, so temps really aren't much of a factor. I'm willing to see how things fare over time, but I'm pretty sure my battery is going to be one of those that makes everyone else's batteries look good. It seems like a lot of change for such a short period of time (4 months, 4000 miles).

I have seen nominal full pack values on you tube (mostly on OBDII harness installation videos) range from 68-77 for LR Model 3's

What's your charging regimen?