Supercharging speeds have improved dramatically over the past decade. The graph below provides some perspective. In order of descending charge rate: 2018 Model 3 LR (Blue), 2015 Model S 85 kWh (Black), 2012 Model S 85 kWh (Red)
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Supercharging Speeds: Who, what, where, why, and when
- Thread starter wk057
- Start date
Your graph for these 2 models is way off the current charging speed. It is currently lower.
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just for interest, this is my supercharging speed since mid-2018 when I started using TeslaFi. the bluer the dot, the longer ago it happened:
You can see pretty clearly that it used to hit 120kW and stay there to about 20%, then fell away pretty gradually all the way to 85%, before dropping steeply to 100%, now it still starts at 120kW (sometimes even 125, but it rockets down to 90kW by about 15% and then falls away gradually to 90%. I've removed all the datapoints where I was sharing, or the battery was cold etc. to get rid of the noise.
You can see pretty clearly that it used to hit 120kW and stay there to about 20%, then fell away pretty gradually all the way to 85%, before dropping steeply to 100%, now it still starts at 120kW (sometimes even 125, but it rockets down to 90kW by about 15% and then falls away gradually to 90%. I've removed all the datapoints where I was sharing, or the battery was cold etc. to get rid of the noise.
Also - working out supercharger speed versus software version gives me this (across the full charge range)
i.e. 2019.16.1 was the fastest charging I ever had, and although it looks like 2020.48.37 might be an improvement against where we have been for the last year, I'm not holding my breath as it might just be based on 2 relatively good charges. My supercharging has been relatively limited in the last year so not that much data to go on.
| Software | Average charging time increase against best |
| 2018.26 3bbd9fd | 1% |
| 2018.32.4 040c866 | 2% |
| 2018.34.1 3dd3072 | 4% |
| 2018.42.3 eb373a0 | 12% |
| 2018.46.2 8f8dc1b | 10% |
| 2018.48.12.1 d6999f5 | 4% |
| 2019.4.2 6ed8818 | 2% |
| 2019.4.3 c63775a | 5% |
| 2019.12.1.1 4b1dd29 | 4% |
| 2019.16.1.1 697c2ff | 0% |
| 2019.20.1 9973c22 | 20% |
| 2019.20.4.2 66625e9 | 16% |
| 2019.28.2 320fba0 | 33% |
| 2019.32.2.1 9b8d6cd | 36% |
| 2019.32.12.2 58f3b76 | 27% |
| 2019.32.12.3 1b89dd1 | 28% |
| 2019.40.2.3 40ef2d4d | 38% |
| 2020.4.1 4a4ad401858 | 36% |
| 2020.24.6.11 3f98504 | 32% |
| 2020.48.12.1 3095698 | 37% |
| 2020.48.37.1 332984f | 26% |
jpvdheijn
Active Member
Very interesting the table you have created. The percentage increase are they based upon the best results of 2019.16.1? Is there also the factor environmental temperature here based upon your increases? That might give you a better comparison on charge times and environmental temperatures.
Helpfull chart!
Helpfull chart!
I don't think I have enough data to start using temperature as another variable for comparison, I don't do huge amounts of supercharging (only long trips) though pre-pandemic I was doing quite a lot of business miles. Supercharging is always mid-long journey though so battery is always running a good temperature.
That's roughly what my speeds were like and how they changed. I haven't taken a road trip in quite a while, though, so I don't know how the real-world experience has changed. How much time is this adding to actual travel? Like, is the extra time more like "I guess I had time for an ice cream" or is it more like "I'm going to be a day late"?
Gtech
Active Member
Yes, when battery is warm SuC speed is roughly the opposite of the SoC so 10% = 90kW, 50% = 50kW, 90% = 10kW...
airborne spoon
Active Member
i have to add about 50% time. so if it says 20 min to leave i add an extra 10 min and its about right. I take a lot of road trips, I've drawn 18,000kW of SC and 21,000kW of home charging. I love that free for life SC
What i do now, if the option is available is stop more often for shorter times. I can take my dog for a walk in 15 min but taking the dog for a 45 min walk is a PITA especially now that its getting warmer and the 115f days are coming soon. With the shorter stops i am still taking the normal 8 hours to complete my trip. I did it once using the tesla nav SC method and it took me about 9.25 hours for the same trip.
ALL the data points i have on that chart are with a warm battery and not on shared stalls and if it was on a urban charger i didn't collect the data point till the charge speed dropped to 70kW to maintain an accurate collection method. If i was driving in the cold or the extreme heat i would always check the data point to compare it with fair weather point to ensure the weather didn't play a role in the speed. and since the car does the on route warmup/cooldown for optimal SC speeds it seems to work quite well as charging in 20f was the same as charging in 110f and the same at 70f.
SmartElectric
Active Member
FYI, your chart is similar to the formula:
kW (supercharging power) = 110-SOC%
rate that I have seen in most 2012-2014 cars and is the same curve as my 2013 Model S had from factory in 2013 and continues to operate at today.
Might be interesting to chart in that way, it will look more like a straight line, sometimes straight lines look nicer than slopes (I'm kidding).
Will have to go back through this and do some specific responses at some point.
Suffice it to say, it turned out that fast charging was very bad for the 60/70/85 packs. It's an odd phenomenon also... as in, the damage done is virtually undetectable even at the cell level until it's too late. Once it's too late, the cell's IR goes up exponentially to the point where it just cant charge/discharge anymore (the failure section is over the course of about 100 cycles).
This actually eventually happened to all of my cells I had under supercharge-equivalent long-term testing, and I've sent some of them to a lab that was interested in the results to breakdown and analyze why this actually happened. Preliminary findings show some sort of insulating/isolating material is built up during high stress charges. Once that buildup crosses a threshold, further charging spreads it more quickly across the plates until the cell reaches the point where charging doesn't supply enough energy to produce/release this insulator. The actual material may be some additive that is precipitated or otherwise chemically produced. I don't really know. I'm also not a chemist. While I have a decent understanding of the principals involved, my terms are probably off here. Still waiting on more details (probably won't get any more info until next year).
The odd thing is that my own testing shows this to be very random. In my testing the first cells didn't show signs of the issue until well over 500,000 equivalent fast charge miles, and some reached around 900,000 fast charge miles. On the other hand, I have 20kW-equiv test cells with almost 2,000,000 miles of equivalent charges showing under 20% degradation, tapered to the point where I'd be surprised if they ever even fail... so fast charging is definitely a factor.
Tesla seems to have discovered this potential issue, ran the numbers on their end, and came up with new thresholds and metrics for how much fast charging to allow and at what levels on these "legacy" chemistries. Since about late 2019, the BMS firmware of all of the pre-100 pack vehicles has an algorithm to calculate fast charge and taper rates based on historical usage data. I've dissected it as best possible from a reverse engineering standpoint, and while the exact thresholds that cause a substantial decrease in charging speed can vary greatly based on different metrics, the maximum rates and best taper rates are much lower than what they could have been previously even on the best packs.
The worst possible output of the new function comes out to about 1/4C CC rate. (So, for an "85" pack that'd be about 19 kW since ~75 kWh real capacity / 4). The worst I've seen in the wild maxes out at 42 kW. This seems excessive.
What's odd (telling?) is that the old charge rate code section is what is used to output the estimated charge time remaining on these packs, even as of the latest code I've looked at (few months ago). This is why, for example, an 85 will start at say, 50 minutes remaining, and 90 minutes later say 20 minutes remaining. Estimates based on the real power data would be more accurate, but would show things like 2+ hours remaining on the screen of some of the worst impacted vehicles... which would probably be worse for PR than showing 30 minutes for 90 minutes.
Anyway... IMO, I think Tesla is being a little too CYA on this one. With the older charge profile, even under the worst conditions in my tests, cells didn't show issues until well past what you'd expect the life of a normal vehicle to be. So people still on older firmware charging faster on their 85s are not likely in any serious danger of having problems. (Barring unrelated BMS issues described elsewhere.)
To be very clear, the issues posed by this are not catastrophic failures (like fire, shorts, explosions, etc). The failures are essentially full degradation down to single digit % original capacity... which would never even happen in a real car anyway since the BMS would freak the heck out long before it got to that point.
Keep in mind that there are other minor factors that Tesla may be taking into account, such as the wear on older vehicle hardware (fast charge contactors or contacts in charge port connectors, for example) that I'm not fully aware of the details on. These definitely have an impact on the safety of fast charging, and there's no technical way for Tesla to measure these items in firmware to determine condition... so I could see them using a low-end real world test metric for that input data, resulting in lower charge rates.
I think Tesla should undo this particular change, since it impacts the usability of older vehicles greatly. I don't think they will, however, for a variety of reasons... not the least of which is that I'd guess it presently has a net positive effect on their bottom line.
TL;DR - Tesla slowed fast charging on pretty much every car produced before about 2017.
Suffice it to say, it turned out that fast charging was very bad for the 60/70/85 packs. It's an odd phenomenon also... as in, the damage done is virtually undetectable even at the cell level until it's too late. Once it's too late, the cell's IR goes up exponentially to the point where it just cant charge/discharge anymore (the failure section is over the course of about 100 cycles).
This actually eventually happened to all of my cells I had under supercharge-equivalent long-term testing, and I've sent some of them to a lab that was interested in the results to breakdown and analyze why this actually happened. Preliminary findings show some sort of insulating/isolating material is built up during high stress charges. Once that buildup crosses a threshold, further charging spreads it more quickly across the plates until the cell reaches the point where charging doesn't supply enough energy to produce/release this insulator. The actual material may be some additive that is precipitated or otherwise chemically produced. I don't really know. I'm also not a chemist. While I have a decent understanding of the principals involved, my terms are probably off here. Still waiting on more details (probably won't get any more info until next year).
The odd thing is that my own testing shows this to be very random. In my testing the first cells didn't show signs of the issue until well over 500,000 equivalent fast charge miles, and some reached around 900,000 fast charge miles. On the other hand, I have 20kW-equiv test cells with almost 2,000,000 miles of equivalent charges showing under 20% degradation, tapered to the point where I'd be surprised if they ever even fail... so fast charging is definitely a factor.
Tesla seems to have discovered this potential issue, ran the numbers on their end, and came up with new thresholds and metrics for how much fast charging to allow and at what levels on these "legacy" chemistries. Since about late 2019, the BMS firmware of all of the pre-100 pack vehicles has an algorithm to calculate fast charge and taper rates based on historical usage data. I've dissected it as best possible from a reverse engineering standpoint, and while the exact thresholds that cause a substantial decrease in charging speed can vary greatly based on different metrics, the maximum rates and best taper rates are much lower than what they could have been previously even on the best packs.
The worst possible output of the new function comes out to about 1/4C CC rate. (So, for an "85" pack that'd be about 19 kW since ~75 kWh real capacity / 4). The worst I've seen in the wild maxes out at 42 kW. This seems excessive.
What's odd (telling?) is that the old charge rate code section is what is used to output the estimated charge time remaining on these packs, even as of the latest code I've looked at (few months ago). This is why, for example, an 85 will start at say, 50 minutes remaining, and 90 minutes later say 20 minutes remaining. Estimates based on the real power data would be more accurate, but would show things like 2+ hours remaining on the screen of some of the worst impacted vehicles... which would probably be worse for PR than showing 30 minutes for 90 minutes.
Anyway... IMO, I think Tesla is being a little too CYA on this one. With the older charge profile, even under the worst conditions in my tests, cells didn't show issues until well past what you'd expect the life of a normal vehicle to be. So people still on older firmware charging faster on their 85s are not likely in any serious danger of having problems. (Barring unrelated BMS issues described elsewhere.)
To be very clear, the issues posed by this are not catastrophic failures (like fire, shorts, explosions, etc). The failures are essentially full degradation down to single digit % original capacity... which would never even happen in a real car anyway since the BMS would freak the heck out long before it got to that point.
Keep in mind that there are other minor factors that Tesla may be taking into account, such as the wear on older vehicle hardware (fast charge contactors or contacts in charge port connectors, for example) that I'm not fully aware of the details on. These definitely have an impact on the safety of fast charging, and there's no technical way for Tesla to measure these items in firmware to determine condition... so I could see them using a low-end real world test metric for that input data, resulting in lower charge rates.
I think Tesla should undo this particular change, since it impacts the usability of older vehicles greatly. I don't think they will, however, for a variety of reasons... not the least of which is that I'd guess it presently has a net positive effect on their bottom line.
TL;DR - Tesla slowed fast charging on pretty much every car produced before about 2017.
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The significant drop in supercharging speed is bad enough, but trying to hide it from the affected owners like that is just deceitful. It's not like the owners won't actually notice that the charging is taking much longer than estimated. Tesla must think we're all just a bunch of idiots.
BigNick
Infamous Fat Sweaty Guy
So Tesla might restore SC speeds in 2025, then, once all the 2016 and earlier cars have exceeded their 8 year warranty period?
Thanks , much appreciated information.
This is indeed sad for two reasons to me: 1) This eliminates any hope of restoration. I thought it would eventually also be restored like they did for the other batteries. 2) indeed keeping the old algorithm to display the estimated duration is cheating the customer.
That being said, I knew in 2015 that it was an adventure with a high risk (bankruptcy, new tech). And bottom line, the car is still doing quite ok, with a better than expected capacity left (90%).
Thanks for the Information, wk.
From your expertise, Is there any interrelation to the Battery Pumps and Powertrain Pump running at 100% for hours after charging to 78% SOC?
Any interrelation to the high vampire drain on firmware 2020.48 (on MCU1, not caused by MCU upgrade...) ?
Thank you!
From your expertise, Is there any interrelation to the Battery Pumps and Powertrain Pump running at 100% for hours after charging to 78% SOC?
Any interrelation to the high vampire drain on firmware 2020.48 (on MCU1, not caused by MCU upgrade...) ?
Thank you!
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