How I Recovered Half of my Battery's Lost Capacity

[Klownicle]

Fellow Houstonian here. I get random talk saying my battery is fine too. Kinda sucks when I've tried everything and a 90% charge sits at 259 or so on my LR RWD M3

90% LR RWD M3 2018 @ 252. Car was "supposed" to be 325, tho bought with 310. I wonder how they factor that in with the warranty? I feel your pain and compound it. Drops 5-10miles every 5-10k miles. I await 30% for warranty. I'm at 57k miles. Coming from other long term electric cars I've been quite disappointed with Tesla's performance. Tesla's checked mine out in the past and they've told me the same thing. All is normal according to fleet data. Yeah all is crappy more like it.

I already adhere to the rules of this thread for my habits, so hasn't been any improvement, just a steady decline.

 

[AlanSubie4Life]

Also even by Teslafi standards 12% is not normal. The average for 30k km is around 5-6% atm.

Umm...we are 100% in agreement -that’s exactly what I just said... (12% about 2-3sigma out - that would be consistent with a typical spread of between 13% and 0% with an average around 6%.). Roughly speaking.

ok, what if your car degrades to 29% now. are you happy with that, because"it is normal" on your 1 year old car?

No that wouldn’t be normal. That would be a clear outlier. There is normal (6% typically, maybe as much as 12-15%, which is also normal, though nearly the worst case, as I have consistently said when indicating it is normal), and abnormal. And anyone seeing this much has had their battery replaced (typically there are other problems). Even in Model S degradation was fastest initially. It’s TBD what the slope of degradation will look like after 3 years for Model 3.

tesla has not been truthful about how much range degradation their vehicles have.

nowhere on teslas websites does it state that after a year you get 70km less rated range after a year.

I think Tesla should be more straightforward about this. But they have a 30% warranty, so it’s reasonable to expect that you’ll be around 15-25% capacity loss after 8 years or so. I’m not a Tesla apologist. It’ll be better when batteries last longer.

 

[Yankees]

90% LR RWD M3 2018 @ 252. Car was "supposed" to be 325, tho bought with 310. I wonder how they factor that in with the warranty? I feel your pain and compound it. Drops 5-10miles every 5-10k miles. I await 30% for warranty. I'm at 57k miles. Coming from other long term electric cars I've been quite disappointed with Tesla's performance. Tesla's checked mine out in the past and they've told me the same thing. All is normal according to fleet data. Yeah all is crappy more like it.

I already adhere to the rules of this thread for my habits, so hasn't been any improvement, just a steady decline.

I don't think most 2018 cars got the 325 "upgrade" — ours (September?) didn't. I had a December '18 P3D+ too that never got the upgrade either.

How are your supercharging habits? Regardless of what I read, I can see in the data that SCing thrashes the battery. As is expected when you're forcing a chemical reaction that fast. I recently had the pleasure of using a V3 and saw 250kW with my own eyes in my own car. I was giggling like a child thinking of what was going on, but at the same time I was cringing thinking of how my battery was being hit in the head with a baseball bat. Thankfully (for the battery, not so much for practicality) the peak rate only lasted for about 30-45s (and, as this was "a big charge" to skip an SC stop, it still took ~35 min).

I think that the true range of these cars when driving speed limit +5 should be stated as whatever they list now -30%[1]. So my 310 RM car should really be listed as 215 RM — wouldn't it be great to actually exceed that once in a while? There is also the phantom drain, it's just different technology that works differently. Reducing the inflated current claims would cover all of this stuff and be much closer to real world expectations. The problem is that they wouldn't be able to convince new-to-EV customers, as we all know the first thing they ask is "how far can it go?" I almost feel dirty when I recite the EPA rating[2] as I know full-well it won't get that in the real world. I do quickly explain that "but, you don't want to go the longest distance, you want to make more frequent stops because of the way batteries charge — you want to charge in the fast sweet spot."

All of this said, because it's technology that works completely differently with different parameters, I would still rather have the Teslas even the way they are now (and they're always improving), than not have them. Probably the best thing is to stop looking at these stats so often and check once in a while to see if you need to do a warranty claim. I love the cars, I love the way they drive, I love the EV life that comes with it (maybe not so much the waiting for supercharging on a roadtrip, but with young kids frequent stops are fine.. for now; it's not the stop that I mind, it's the length of the stop -- I can only eat so much junk food ).

Edit: all this said, I did have my second longest drive in my car's history a few days ago, 222 miles heading east between the Deming, NM and Van Horn, TX SuperChargers (skipping El Paso). Average speed was 69 MPH, max speed 83 MPH, 76% battery usage (96%->20%), 97.6% efficiency. Not too shabby! But, tailwind-assisted, and I did keep a light foot.

---
[1] Again, TX has 75-80 MPH speed *limits* in most places, and 85 MPH on a few select highways. Regular traffic goes faster than the limit, including semis sometimes (not really safe, but they do it).. you don't want to be the slow car semis have to pass at these speeds, for safety.
[2] Ironically, I feel a bit better as current cars are rated quite a bit higher than my 2018 310 RM, so when I say "you can go 300 miles on a full charge if you really want to, but that's not the best way" I don't feel that bad anymore.

 

[AlanSubie4Life]

I had a December '18 P3D+ too that never got the upgrade either.

There was no increase for the 2018 P3D+. It only applied to LR RWD. Possibly not all of them as you say (it’s hard to say without detailed data - it was possible to get the range upgrade but never go above 310 rated miles, for example 293 rated miles -> 307 rated miles).

 

[KenC]

I don't think most 2018 cars got the 325 "upgrade" — ours (September?) didn't. I had a December '18 P3D+ too that never got the upgrade either.

How are your supercharging habits? Regardless of what I read, I can see in the data that SCing thrashes the battery. As is expected when you're forcing a chemical reaction that fast. I recently had the pleasure of using a V3 and saw 250kW with my own eyes in my own car. I was giggling like a child thinking of what was going on, but at the same time I was cringing thinking of how my battery was being hit in the head with a baseball bat. Thankfully (for the battery, not so much for practicality) the peak rate only lasted for about 30-45s (and, as this was "a big charge" to skip an SC stop, it still took ~35 min).

I think that the true range of these cars when driving speed limit +5 should be stated as whatever they list now -30%[1]. So my 310 RM car should really be listed as 215 RM — wouldn't it be great to actually exceed that once in a while? There is also the phantom drain, it's just different technology that works differently. Reducing the inflated current claims would cover all of this stuff and be much closer to real world expectations. The problem is that they wouldn't be able to convince new-to-EV customers, as we all know the first thing they ask is "how far can it go?" I almost feel dirty when I recite the EPA rating[2] as I know full-well it won't get that in the real world. I do quickly explain that "but, you don't want to go the longest distance, you want to make more frequent stops because of the way batteries charge — you want to charge in the fast sweet spot."

All of this said, because it's technology that works completely differently with different parameters, I would still rather have the Teslas even the way they are now (and they're always improving), than not have them. Probably the best thing is to stop looking at these stats so often and check once in a while to see if you need to do a warranty claim. I love the cars, I love the way they drive, I love the EV life that comes with it (maybe not so much the waiting for supercharging on a roadtrip, but with young kids frequent stops are fine.. for now; it's not the stop that I mind, it's the length of the stop -- I can only eat so much junk food ).

Edit: all this said, I did have my second longest drive in my car's history a few days ago, 222 miles heading east between the Deming, NM and Van Horn, TX SuperChargers (skipping El Paso). Average speed was 69 MPH, max speed 83 MPH, 76% battery usage (96%->20%), 97.6% efficiency. Not too shabby! But, tailwind-assisted, and I did keep a light foot.

---
[1] Again, TX has 75-80 MPH speed *limits* in most places, and 85 MPH on a few select highways. Regular traffic goes faster than the limit, including semis sometimes (not really safe, but they do it).. you don't want to be the slow car semis have to pass at these speeds, for safety.
[2] Ironically, I feel a bit better as current cars are rated quite a bit higher than my 2018 310 RM, so when I say "you can go 300 miles on a full charge if you really want to, but that's not the best way" I don't feel that bad anymore.

No doubt EVs need to be driven differently than ICE, so it takes a little education and habit change. Because the SC sweet-spot is between about 10 and 60% SOC, that's half a battery, which is roughly 110 to 150 miles. Thus, as long as superchargers are placed in that range on your trip, you just drive as fast as you like and do your 10 to 15 minute charge. Around here, the SC placement seems optimal for a LR, but less-so for smaller battery sizes. And some areas of the country, SC placement may be less optimal and requires a bit of planning. But for my area, I haven't noticed any real change from driving an ICE. My regular trips all take me the same amount of time it has for the last 40 years.

I do wish Tesla would do a better job educating people on how to right-size their choice of battery. Factor in deg, factor in speed and cold, test simulations for their most common trips. They really ought to buy ABRP.

 

[Dave EV]

How are your supercharging habits? Regardless of what I read, I can see in the data that SCing thrashes the battery. As is expected when you're forcing a chemical reaction that fast. I recently had the pleasure of using a V3 and saw 250kW with my own eyes in my own car. I was giggling like a child thinking of what was going on, but at the same time I was cringing thinking of how my battery was being hit in the head with a baseball bat. Thankfully (for the battery, not so much for practicality) the peak rate only lasted for about 30-45s (and, as this was "a big charge" to skip an SC stop, it still took ~35 min).

Yes - for that reason, I do wish that Tesla had the option of reducing Supercharger speed to somewhere between 70-90% of peak allowable charging speeds to minimize Supercharger induced capacity loss. This would be an across the-board reduction in speed of what is allowable at that SOC/temperature. I suspect that a small reduction in speeds might result in a significant reduction in rate of capacity loss. This would be important for people who can't charge at home and have to rely on Supercharging. It is also nice for that scenario when you are grabbing some food and you know it'll take longer than how fast the car charges.

If the Supercharger is full, you would want to disable this feature to maximize throughput and open up spaces for other people to charge.

No doubt EVs need to be driven differently than ICE, so it takes a little education and habit change. Because the SC sweet-spot is between about 10 and 60% SOC, that's half a battery, which is roughly 110 to 150 miles. Thus, as long as superchargers are placed in that range on your trip, you just drive as fast as you like and do your 10 to 15 minute charge.

It's interesting - on road trips, I have found that sometimes you want to charge faster than what the car/Supercharger can handle, but other times it's too fast. See above.

Back on topic, my 2018 LR RWD is currently sitting around 300 mi estimated range after 24k miles (have not driven much in the last year). I mostly charge to 70%, then recharge at ~30%. In the last year, I've been charging to either 50% or 60%. Indicated max range dropped quickly the first few months of COVID when it spent a lot of time between 30-50%, but has stabilized in the 295-300 mi range. Currently the cells have about 8 mV of imbalance in the middle of the SOC range.

If the 10% loss of range is real, it's a bit worse than what I was expecting after seeing Model S capacity loss reports w/the 85 kWh battery, but I do expect it to flatten out at this point. But this far better than my last EV which was down 16-18% after a similar amount of time/miles.

 

[SageBrush]

Back on topic, my 2018 LR RWD is currently sitting around 300 mi estimated range after 24k miles (have not driven much in the last year). I mostly charge to 70%, then recharge at ~30%. In the last year, I've been charging to either 50% or 60%. Indicated max range dropped quickly the first few months of COVID when it spent a lot of time between 30-50%, but has stabilized in the 295-300 mi range. Currently the cells have about 8 mV of imbalance in the middle of the SOC range.

Our cars are twins and our charging routines very similar. Mostly my displayed range extrapolated to 100% SoC is ~ 312 miles +/- about 1%
I see 4 - 6 mV in the pack via SMT.

How much degradation has there been ? Well, that is almost a philosophical question since there arguably different reasonable ways to calculate based on the capacity of a new battery, the existence of some variation in battery capacity from the factory, and the known 'settling in' period of Li-x technology. My most confident statement is to start from capacity/range after a year and follow the trend thereafter. FWIW though, my car arrived with 312 miles displayed, and bumped up to 316 miles after the Tesla update in late 2018 that supposedly displayed hidden range up to 325 miles. So my contention is that my pack was about 316 miles when 6 months old, and about 312 miles now.

I was a bit bummed that I never saw 325 miles, but the pack has been rock solid and the degradation curve for the past two years is negligible. Here's hoping it stays that way.

 

[Yankees]

Yes - for that reason, I do wish that Tesla had the option of reducing Supercharger speed to somewhere between 70-90% of peak allowable charging speeds to minimize Supercharger induced capacity loss. This would be an across the-board reduction in speed of what is allowable at that SOC/temperature. I suspect that a small reduction in speeds might result in a significant reduction in rate of capacity loss. This would be important for people who can't charge at home and have to rely on Supercharging. It is also nice for that scenario when you are grabbing some food and you know it'll take longer than how fast the car charges.

While this is a good idea for the current cars, it's not a long term solution because even faster charging is what's needed. I think a change in bat chem is what's really needed to not be affected by fast charging and deep cycles and number of cycles as much. I believe their LFP batteries for mass-market models like the 3/Y/S/X non-Plaid, perhaps even the CT, could help with this, at the cost of energy density (=more mass).

I was a bit bummed that I never saw 325 miles, but the pack has been rock solid and the degradation curve for the past two years is negligible. Here's hoping it stays that way.

I thought the same of my pack! It sat at 309ish for the longest time, for years.. then took an abrupt nosedive into the abyss (well.. went from sub 0.3% to over 5% deg as of today). Nothing of note happened around that time, no SuperCharging, nothing, just some software upgrades.

 

[Candleflame]

While this is a good idea for the current cars, it's not a long term solution because even faster charging is what's needed. I think a change in bat chem is what's really needed to not be affected by fast charging and deep cycles and number of cycles as much. I believe their LFP batteries for mass-market models like the 3/Y/S/X non-Plaid, perhaps even the CT, could help with this, at the cost of energy density (=more mass).

I thought the same of my pack! It sat at 309ish for the longest time, for years.. then took an abrupt nosedive into the abyss (well.. went from sub 0.3% to over 5% deg as of today). Nothing of note happened around that time, no SuperCharging, nothing, just some software upgrades.

im sure lfp batteries will be used in all teslas. they have clear advantages in longevity and ability to be repeatedly charged to 100% which makes MORE than up for the small amount of reduced capacity.

 

[scottf200]

I've seen the service manual excerpt for the model 3 posted a few times. The BMS starts balancing at voltage above 4.0

Quick G-Sheet to double check what SoC that would be.

 

[Candleflame]

I thought that cells get balanced below 90% already and that the 90% was a myth?

 

[scottf200]

I thought that cells get balanced below 90% already and that the 90% was a myth?

Maybe ... I was just going by the person saying they saw excerpts from the service manual about the voltage of 4.0.

 

[Candleflame]

Maybe ... I was just going by the person saying they saw excerpts from the service manual about the voltage of 4.0.

Is there any proof of that though? I.e. someone who does have a bit of cell imbalance keeping their car below i.e. 90% and see if it still balances? Interestingly most if not all cars seem to be in good balance anyway ie. Less than 1% rangeloss suggesting that the car may have other ways to balance the pack than the bleeder circuits.... Or possibly a 100% charge is enough to instantly rebalance the pack.

Also i seem to recall that some owners who do refer to the 4v limit state that their car reads above 4v already in the high 70s%...

 

[SageBrush]

Quick G-Sheet to double check what SoC that would be.

Is there a presumption of a SoC and Voltage linear relationship in your sheet ?

 

[scottf200]

Is there any proof of that though? I.e. someone who does have a bit of cell imbalance keeping their car below i.e. 90% and see if it still balances? Interestingly most if not all cars seem to be in good balance anyway ie. Less than 1% rangeloss suggesting that the car may have other ways to balance the pack than the bleeder circuits.... Or possibly a 100% charge is enough to instantly rebalance the pack.

Also i seem to recall that some owners who do refer to the 4v limit state that their car reads above 4v already in the high 70s%...

Is there a presumption of a SoC and Voltage linear relationship in your sheet ?

Certainly it is not. I was just doing something simple to see where the 4v fell. Various sources show charts of volts vs SOC. If 4v is reasonably accurate then it could happen at a lower SOC. Sorry for any confusion I've added.

I have ScanMyTesla so I could grab this data and chart it but I'm sure that has been done many times. Tesla appears to have tweaked their battery chemistry/content over the years so it certainly varies because of that. i.e. I had a 2016 90 X that I think is different from my current 2017 100 X. Certainly different on MYs of the 3/Y too.

Below via: 41. LCO, LFP, NMC... CRYPTIC LIVES OF THE CATHODE - Qnovo

 

[scottf200]

...
This means that the S/X BMS can run the calibration computations a lot easier and lot more often than the Model 3. 15-20 minutes with the contactor open is enough to get a set of OCV readings. This can happen while you're out shopping or at work, allowing the BMS to get OCV readings while the battery is at various states of charge, both high and low. This is great data for the BMS, and lets it run a good calibration fairly often.

On the Model 3, this doesn't happen. With frequent small trips, no OCV readings ever get taken because the voltage doesn't stabilize before you drive the car again. Also, many of us continuously run Sentry mode whenever we're not at home, and Sentry mode keeps the contactor engaged, thus no OCV readings can be taken no matter how long you wait. For many Model 3's, the only time OCV readings get taken is at home after a battery charge is completed, as that is the only time the car gets to open the contactor and sleep. Finally, 3 hours later, OCV readings get taken.

But that means that the OCV readings are ALWAYS at your battery charge level. If you always charge to 80%, then the only data the BMS is repeatedly collecting is 80% OCV readings. This isn't enough data to make the calibration computation accurate. So even though the readings are getting taken, and the calibration computation is being periodically run, the accuracy of the BMS never improves, and the estimated capacity vs. actual capacity continues to drift apart.
...

Something that changed since this post is that there is a charging at a departure time built-in option. This means if your drive/usage is varying by the day of the week (workdays or work from home days or whatever) ... then your car will sit at the previous drives ending SOC % until the time the car calculates it needs to start charging to meet your 'departure time'.

This adds an *automatic* variance to the OCV readings which gives the BMS more variables for the calibration computations. So even if you pay a fixed rate for your kWh you can get benefit to using 'Scheduled Departure'. I'm in a TOU variable rate *but* the price/kWh is lowest until about 5am. That is when I set my departure time to every day. It usually ends around 4:30am.

Scheduled Departure: For any location, such as Home, you can simply plug in Model [S/3/X/Y] and select a time for when you want your vehicle to be ready to drive. Once your specified time is set, Model [S/3/X/Y] prepares itself by determining the best time to start charging to optimize energy costs, Battery longevity, and ensure charging completes in time for your drive. Your vehicle also preconditions the cabin to a comfortable temperature and warms the Battery. To set up a scheduled departure time, go to Charging > Scheduled Departure > Schedule and follow the onscreen instructions to customize your schedule.

 

[El joe]

I don't think most 2018 cars got the 325 "upgrade" — ours (September?) didn't. I had a December '18 P3D+ too that never got the upgrade either.

I've wondered about this. I bought my 2018 LR AWD used last October and at most, my range is somewhere between 297 and 300. That would be a decent-sized drop from a 325 max with upgrade but if it's just a drop from 310, I'm not too worried.

 

[KenC]

I've wondered about this. I bought my 2018 LR AWD used last October and at most, my range is somewhere between 297 and 300. That would be a decent-sized drop from a 325 max with upgrade but if it's just a drop from 310, I'm not too worried.

The range bump didn't apply to our 2018 LR-AWD models. 310 is it.

 

[El joe]

The range bump didn't apply to our 2018 LR-AWD models. 310 is it.

Thanks for the clarification!

 

[Candleflame]

Thanks for the clarification!

Afaik its not a range bump anyway. The awd jsut got uprated and the performance downrated or more to say the 20 inch wheels got downrated. If you put 18 inch wheels on and change them in the menu it goes back up.