TeslaFi battery report range increase of over 10 miles after update ?

[Alset2]

Just wondering if this is normal? I have the E battery so I thought I missed out on the LR+ .

It came after my charge today - and I updated to 2020.28.5 this morning before the charge.

It jumped from 348 yesterday to 363 today (its been hovering in the 350 - 348 range for a month or so)

Any thoughts?

And here I thought I had bad degradation ...lol

Neil

 

[serendipitous]

It's normal but don't get too excited. Do you have a LR (non-Plus?). If so 363 seems low, but either way - the change in 2020.8.5 was to the fixed EPA consumption figure that's used to generate your miles remaining display. The BMS takes the estimated kWh capacity of the pack, divides it by this constant, and presents the result as your range if you have your display set to miles instead of percentage. That constant was around 288Wh/mi in my -E pack MS Performance, and it appears it's been changed to 282Wh/mi.

There's no actual change in range or efficiency as a result of this change - it's just catching up to a slightly improved EPA rating for the same car. When sold, my car was rated at 345 miles of range, and they later updated it to 348, but mine never reflected that adjusted constant. I believe even new cars sold when it said 348 continued to use/show the old constant as well.

The only real result of this change is to make it harder to track ongoing battery degradation via apps like TeslaFi According to ScanMyTesla, my pack has a nominal full capacity of 95.5kWh now, and 5kWh of buffer, so 90.5 usable. I only received my cable recently so I don't know what it was when new, but it appears recent packs no longer had the 102.4 expected capacity of the earlier ones - possibly a reflection of more conservative battery management they could get away with now that efficiency is so improved on Ravens.

 

[Alset2]

Thank you for the reply.

i have always thought it a little low .It is A LR (non +) with 21" wheels
My last SMT was beginning of July and it had NOM BAT at 94.2%
About 6 weeks earlier it was at 95.1

I bought car with 600 miles on it and got SMT 3 months after I got the car (95.1%)
The very 1st Teslafi report I got it was right at 360 miles range , it then has continued to drop and has been hovering at 350 miles.

I guess at the end of the day 10 miles does not really matter, I just would like to know that I have healthy battery

Thanks again

 

[Pluturi]

Glad (sort of) to hear I’m not alone. I got SMT after 2000 miles on my 2020 MS Raven (battery pack E) and it says my nominal pack is 96. I was bummed because I expected the 102.4, and I thought something was wrong with the car.

 

[Alset2]

Yes, Ive done a LOT of reading and it seems that the 100kw packs are pretty good in general .
I just feel like almost 6% degradation is on the high side...maybe?? IDK lol

I am also starting to think that the BMS reading for NOM BAT CAP maybe a bit dynamic in the sense that it can vary a percent or so just because...I have no proof of this (maybe wishful thinking).

I also have never checked it at a high charge .I'm always checking it at 70-80% and some post I read lead me to think maybe state of charge can affect the NOM BAT CAP percentage reading some??

So then I think about this...1% is about 3 miles??? so I laugh at myself spending all of this energy worrying about 3 or 4 miles lol

My real concern is if this trend continues and I lose 15% in 2 years...that would be distressing .

But I got what I got so I will deal with it.
However , I really do enjoy learning about these things, I find it all very interesting .

 

[Pluturi]

Agree 100%. I’m unwilling to deep cycle the battery just to see if that improves it as some have claimed, but I did take it up to 100% SOC once and it had no effect on the nominal. Everything I’ve seen says that degradation is high at the beginning and then levels off, so I’m not going to worry about the longer term (too much).

 

[serendipitous]

i have always thought it a little low .It is A LR (non +) with 21" wheels
My last SMT was beginning of July and it had NOM BAT at 94.2%

Two questions - when you say nom bat at 94.2%, do you mean Nominal Full Pack Capacity of 94.2kWh? I don't see the "Full Pack Capacity When New" signal on the CANBUS like the Model 3 has, so I don't know how SMT would calculate a % of capacity. I do see mine vary a bit. It was 95.3 when I first got my SMT cable, and rose to 95.5 after letting it get low and charging to full and letting it balance for a while at 100%. In one weird instance it dropped to 90.4 after I'd come home at very low charge, charged a little, and then the car suddenly decided it gained ~10% (as though the projected full capacity dropped) while not charging as the car cooled down. So it's definitely dynamic as the BMS does its best to estimate capacity.

And second, could you or anyone else confirm whether cars with 21" wheels actually show different Miles Remaining figures than the base 19" wheels? I'm curious whether it actually uses a different EPA figure when calculating. I bought mine with 19" wheels, and my range reflected roughly the 345 mile range expected. I replaced them with (non-OEM) 21" wheels and used the Wheel Configuration setting to change them to 21s, but my range calculation inside (and what TeslaFi receives via the API) still uses the same factor as before.

 

[Twiglett]

This is why I have such an issue with TeslaFi calling it a battery degradation report when it's nothing of the sort.

 

[Pluturi]

And second, could you or anyone else confirm whether cars with 21" wheels actually show different Miles Remaining figures than the base 19" wheels? I'm curious whether it actually uses a different EPA figure when calculating. I bought mine with 19" wheels, and my range reflected roughly the 345 mile range expected.

I can give one data point. I changed from 19” to Tesla 21” and had the service center confirm the updated configuration I put in the car. My expected range didn’t change.

 

[Alset2]

Two questions - when you say nom bat at 94.2%, do you mean Nominal Full Pack Capacity of 94.2kWh? I don't see the "Full Pack Capacity When New" signal on the CANBUS like the Model 3 has, so I don't know how SMT would calculate a % of capacity. I do see mine vary a bit. It was 95.3 when I first got my SMT cable, and rose to 95.5 after letting it get low and charging to full and letting it balance for a while at 100%. In one weird instance it dropped to 90.4 after I'd come home at very low charge, charged a little, and then the car suddenly decided it gained ~10% (as though the projected full capacity dropped) while not charging as the car cooled down. So it's definitely dynamic as the BMS does its best to estimate capacity.

And second, could you or anyone else confirm whether cars with 21" wheels actually show different Miles Remaining figures than the base 19" wheels? I'm curious whether it actually uses a different EPA figure when calculating. I bought mine with 19" wheels, and my range reflected roughly the 345 mile range expected. I replaced them with (non-OEM) 21" wheels and used the Wheel Configuration setting to change them to 21s, but my range calculation inside (and what TeslaFi receives via the API) still uses the same factor as before.

Here, I will attach my SMT screenshot because I think I am using wrong terminology

But yes, am referring to the NOM FULL PACK

As far as 19" vs 21" im not sure. My car was rated at 373 miles but was told by sales that the 21" knock some off . My projected range via Tesla app and TeslaFI were in the low 360s mile range a few months ago.

I am pretty sure that when I got the car the Tesla app was showing the same 363-364 miles at 100% (projected) .

The one below was my 1st scan back on May 15th :

 

[serendipitous]

Here, I will attach my SMT screenshot because I think I am using wrong terminology

Gotcha. Thanks. I believe your car was also 370 rated (with 19" wheels) just prior to the website change that took it to 373 (and mine to 348), so I think that's the factor they were using at the time of your May snapshot. So it looks like Tesla does not use different constants for the EPA range/estimated mileage based on wheel selection.

Furthermore, I believe the SOC display when set to distance is based upon the full capacity including the buffer/reserve based on a couple datapoints I captured - the math doesn't seem to work if it was using the Usable capacity. When set to %, the SOC display excludes the buffer ([Usable - Buffer] / [Nominal Full - Buffer]). Also of note is that our cars have 5kWh of buffer whereas older ones always had 4kWh.

And to confirm, yes you're looking at the right thing (Nominal Full Pack) but just using the wrong units - it's kWh, not %. So your battery back in May had 95.1kWh, a little less than mine does (I'm at ~13k miles, about 10 months), and even less now. Looks like the "ideal" factory full capacity for our packs is around 98kWh.

If you frequently keep the car in a tight battery range (e.g. 50%-80%) then I would bet you don't actually have such significant degradation (which still isn't too bad), but rather the BMS has just drifted off on its estimate of capacity - there's no real way to tell how much capacity a battery has from a single measurement of voltage, so the BMS has to do coulomb counting and other magic to estimate the voltage vs capacity curve, which is non-linear to add further difficulty. Although it likely won't change anything in practice, you could drain down to 5% and do a full charge and probably increase your full pack estimate as the BMS recalculates how much energy it took to drain the voltage down to its lower threshold and fill it back up.

 

[Alset2]

Gotcha. Thanks. I believe your car was also 370 rated (with 19" wheels) just prior to the website change that took it to 373 (and mine to 348), so I think that's the factor they were using at the time of your May snapshot. So it looks like Tesla does not use different constants for the EPA range/estimated mileage based on wheel selection.

Furthermore, I believe the SOC display when set to distance is based upon the full capacity including the buffer/reserve based on a couple datapoints I captured - the math doesn't seem to work if it was using the Usable capacity. When set to %, the SOC display excludes the buffer ([Usable - Buffer] / [Nominal Full - Buffer]). Also of note is that our cars have 5kWh of buffer whereas older ones always had 4kWh.

And to confirm, yes you're looking at the right thing (Nominal Full Pack) but just using the wrong units - it's kWh, not %. So your battery back in May had 95.1kWh, a little less than mine does (I'm at ~13k miles, about 10 months), and even less now. Looks like the "ideal" factory full capacity for our packs is around 98kWh.

If you frequently keep the car in a tight battery range (e.g. 50%-80%) then I would bet you don't actually have such significant degradation (which still isn't too bad), but rather the BMS has just drifted off on its estimate of capacity - there's no real way to tell how much capacity a battery has from a single measurement of voltage, so the BMS has to do coulomb counting and other magic to estimate the voltage vs capacity curve, which is non-linear to add further difficulty. Although it likely won't change anything in practice, you could drain down to 5% and do a full charge and probably increase your full pack estimate as the BMS recalculates how much energy it took to drain the voltage down to its lower threshold and fill it back up.

Duhhh...LOL I knew we were talking about KWh ....sorry about that % confusion ...heck, if you cant laugh at yourself, you're missing the best joke in town, right?

Anyway, I actually do stay in a very constrained charge range , usually less than 10% . At least once or twice a week I get it down to 50 or 60% . And then once or twice a month I go down to 20% (just my travel habits, not on purpose) . I keep it charged to 80% normally although for a while I was charging to 95% when I first got the car because I thought it helped balance the cells, but I have settled on 80% unless going on a trip.

My office is only 3KWhs away so I use 6 per day most of the time . I also charge every day except for weekends .

Honestly, I don't think I want to waste a 100% charge just to get . (point) 5 Kwhs showing in my nominal battery reading, Id rather save those charges for when they are needed. BUT , next time i need one I will check SMT and see what happens.
As of now I have simply decided to log a SMT screenshot once a month for both my S and my wife's M3 .I take a screen shot and then put them in a folder that logs date a mileage (for 3)

I will probably put together a spread sheet after I get a few months data just to consume more of my brain...lol-I like spread sheets and data, what cna i say??

Thanks for the reply and info.

 

[ran349]

Duhhh...LOL I knew we were talking about KWh ....sorry about that % confusion ...heck, if you cant laugh at yourself, you're missing the best joke in town, right?

Anyway, I actually do stay in a very constrained charge range , usually less than 10% . At least once or twice a week I get it down to 50 or 60% . And then once or twice a month I go down to 20% (just my travel habits, not on purpose) . I keep it charged to 80% normally although for a while I was charging to 95% when I first got the car because I thought it helped balance the cells, but I have settled on 80% unless going on a trip.

My office is only 3KWhs away so I use 6 per day most of the time . I also charge every day except for weekends .

Honestly, I don't think I want to waste a 100% charge just to get . (point) 5 Kwhs showing in my nominal battery reading, Id rather save those charges for when they are needed. BUT , next time i need one I will check SMT and see what happens.
As of now I have simply decided to log a SMT screenshot once a month for both my S and my wife's M3 .I take a screen shot and then put them in a folder that logs date a mileage (for 3)

I will probably put together a spread sheet after I get a few months data just to consume more of my brain...lol-I like spread sheets and data, what cna i say??

Thanks for the reply and info.

From your second screenshot above it looks like your charge constant( the factor that converts NomFullPack to rated miles), is .270, since 95.1/.270 = 352.22, which your car reports as 352 rated miles.

It sounds like recently they changed that constant value since you have more rated miles now.
Could you post an SMT screenshot of your current configuration to see what they changed the constant value to that now gives you more rated miles?

 

[Alset2]

It sounds like recently they changed that constant value since you have more rated miles now.
Could you post an SMT screenshot of your current configuration to see what they changed the constant value to that now gives you more rated miles?[/QUOTE]

Here is one from a few minutes ago , does this help answer your question?

 

[ran349]

It sounds like recently they changed that constant value since you have more rated miles now.
Could you post an SMT screenshot of your current configuration to see what they changed the constant value to that now gives you more rated miles?

Here is one from a few minutes ago , does this help answer your question?

Thanks but it needs to show the rated miles value also in order to do the calculation.
That is, it needs to show the full rated range value along with the nominal full pack value.

 

[Alset2]

ok, ill pull another one tomorrow .

Thanks again

 

[Alset2]

Here we go, I pulled this one from the BATTERY tab . It shows ATW down rated range

 

[ran349]

Here we go, I pulled this one from the BATTERY tab . It shows ATW down rated range

View attachment 570300

Not quite right. You need to show full rated range.

 

[serendipitous]

Not quite right. You need to show full rated range.

It's good enough. His new constant is 69400Wh/282mi = 246Wh/Mile. (It's nominal minus buffer - the usable capacity, that's used for the Rated Range math)

This compares to his earlier shot which was 69300Wh / 271 miles = 255 or 256 Wh/Mile.

 

[ran349]

It's good enough. His new constant is 69400Wh/282mi = 246Wh/Mile. (It's nominal minus buffer - the usable capacity, that's used for the Rated Range math)

This compares to his earlier shot which was 69300Wh / 271 miles = 255 or 256 Wh/Mile.

That's not correct. The rated range constant is equal to full pack divided by full rated miles. That is the actual constant that Tesla uses in their firmware when calculating rated miles. It is an exact number that never changes, unless Tesla changes it in the firmware, which it looks like they did in his case.