So Tesla engineering and service contacted me back. They are saying my pack appears healthy (they estimate much better than 240 rated) and that the main issue is with the algorithm for "some packs" is not right when calculating rated range. They think my charging habits are proper and that I haven't rangel charged very much. I was told an upcoming firmware update would improve the algorithm to a more realistic number in the near future and that my range degradation isn't what the numbers indicate. I will await the update. A "file" is open, and they are watching my specific numbers.
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mknox
Well-Known Member
Sorry if I missed it, but did they do this "over the air" or did a Service Center have to do some work?
I have thought with the number of used cars now popping up on the market that it would be useful to have some sort of battery health check data that the seller could provide. This is the big unknown and variable with EVs. It would be great if Tesla could provide some sort of diagnostic report, even if for a fee, to owners who are interested in selling (or just interested).
See?
And even that improved algorithm will have its own issues and 'degradation', no way around it.
Battery is not like a bottle with a fixed volume, its more like a balloon.
Range estimation is like trying to determine its volume by measuring surface tension.
I look forward to hearing the outcome of this firmware update. Did they ever tell you how many miles your refurbed A pack had on it at the time of the swap?
So what reason do you see that range numbers are not comparable between two cars with the same firmware and the same A battery? If you skim through this thread you will notice that 240 seems quite low even for an A battery. And compare that to what walla2 used to have (A battery with 260+ rated and only a few thousand miles). I see a clear distinction between the packs.
hans
P631
If that were true then they have done a very bad job of estimating it will take 1 minute since the normal taper should be more predictable.
Cottonwood
Roadster#433, Model S#S37
I tend to agree that it is the end of the taper curve. Besides, who cares if it takes 75 minutes to get to 99.6% SOC and another hour to get that last 0.4%. I'm guessing at plausible percentages and the 75 minutes is from the Tesla graph on the Tesla Motors Supercharger Page
As for bleed current, it is not much power. See Pics/Info: Inside the battery pack - Bleed Resistors. If we use that 0.1 Amp max bleed current and the nearly full battery Voltage of about 400 Volts, then max bleed power is about 40 Watts. At 240 Volts and 90% efficiency, that is an AC charge current of 0.19 Amps. During those last 15 to 60 minutes at the end of a 100% charge, I always see a few Amps on the 240 Volt AC or several hundred Watts; that is a lot more power than needed for just balancing, bleed power.
No, you don't see a clear distinction between packs but clear distinction between the numbers those (different?) range estimation algorithms spat out.
No two packs are driven and charged under exactly the same conditions and no two packs are made exactly the same.
There is only one somewhat reliable capacity estimation method:
1. discharge until some low cutoff voltage is reached
2. charge until some high cutoff voltage is reached
3. count Wh used between those low and high cutoff voltages
Those Wh are the upper limit on possible battery capacity. It can be less, but not more.
Now discharge the battery under some predetermined discharge profile #1 and count Wh 'extracted' until that low cutoff is reached again. You get capacity estimation #1.
Repeat with a different discharge profile #2 and again count Wh 'extracted'. You will get a different number of Wh. That is capacity estimation #2.
Repeat with yet another discharge profile #3 to get capacity estimation #3.
Repeat with discharge profile #1 at different temperature. You will reach to capacity estimation #4.
Etc.
See the problem?
And don't forget that by doing such measurements, battery degrades.
So, the only thing a rational man can do is to stop obsessing about 0,5% range differences. It means nothing and nothing at all. There is a computer in the model S that knows a bit more about the battery than "249 mile rated range". It will tell you when there is time to call Tesla.
265 miles range does not mean 265 mile range, it means
a) you will probably get to that town 200 miles away
b) you might get to that town 250 miles away
c) you probably wont be able to drive to that town 300 miles away
Just found out that I have the a pack. What has been determined the difference between them is?
hans
P631
Do you mean a 60KWh A pack? If so then I don't think there is much at all known about the differences with later 60 KWh packs. It is believed that the cells you have are similar to the ones inside the 85KWh B packs so they are not limited to lower supercharge rates like the 85KWh A packs.
Charging to 90% for a few weeks has pushed up my ideal range from 259 miles to 266 miles, and a 100% charge has gone from 288 miles to 296 miles. This is with range mode OFF. If I turn range mode ON, my range increases by 3-4 miles. That gets me the full 300 miles. So no degradation here after 14 months and 14,500 miles. Back in March my 100% charge hit 301 miles with range mode on, so it's the same as today.
40,000 +
90% 225 mi
Range 255 mi
A Battery
Many range charges
Many SC charges
otherwise 80 - 90%
90% 225 mi
Range 255 mi
A Battery
Many range charges
Many SC charges
otherwise 80 - 90%
glhs272
Unnamed plug faced villian
Latest 100% charge yields 206 miles rated range, although didn't quite charge to completion. Still, seems to be the first indication of measurable range loss at 34K miles.
taurusking
Member
Hi Guys
Newbie here...bought my MS only a week back
Had 6000 miles on it when I bought it..
Currently has 6500 miles or so
Rated range was 265 when I took delivery of the car
Yesterday when I range charged the car with 5 mins remaining the rated range was 263 miles
Today I charged to 90% and my rated range is 236 miles...usually when I charge to 90% the rated range is 240 miles
Questions:
My charging ends at 5am and when I checked this morning it was 9am ...so do you guys think that it would have dropped from 240 to 236 miles in 4 hours?
I will be using MS for long trips once every month ...is it o. k to range charge every month?
Yesterday when I was driving I noticed that my projected range was more than rated range...is that possible...I had about 50 miles left on the rated range when I reached home but projected range was 75 miles or so... which of this is more dependable?
Just wondering.
Thanks
Newbie here...bought my MS only a week back
Had 6000 miles on it when I bought it..
Currently has 6500 miles or so
Rated range was 265 when I took delivery of the car
Yesterday when I range charged the car with 5 mins remaining the rated range was 263 miles
Today I charged to 90% and my rated range is 236 miles...usually when I charge to 90% the rated range is 240 miles
Questions:
My charging ends at 5am and when I checked this morning it was 9am ...so do you guys think that it would have dropped from 240 to 236 miles in 4 hours?
I will be using MS for long trips once every month ...is it o. k to range charge every month?
Yesterday when I was driving I noticed that my projected range was more than rated range...is that possible...I had about 50 miles left on the rated range when I reached home but projected range was 75 miles or so... which of this is more dependable?
Just wondering.
Thanks
Last edited:
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