@dmurphy wasnt addressing that part to you specifically, but to the multitude of people who "rail at the wind" about lost range they are not actually driving.
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Sad sad battery
- Thread starter KetchupKilla
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@dmurphy wasnt addressing that part to you specifically, but to the multitude of people who "rail at the wind" about lost range they are not actually driving.
Oh, I totally get that. Which is why I rarely even read these kinds of threads at all anymore
There's certainly some loss (as there is with *any* battery) - but that's not a direct correlation with what the range estimator shows. I know you understand that -- so no, my second half wasn't directed at you, at all! Sorry if I didn't clarify - that's just general grousing.
The estimation is exactly that - an estimate - and the quicker we (as a community) accept that and move on, the better life is. You're absolutely right - if there's 100 of us, there's 300 usage patterns; anything trying to attribute how we use these vehicles to actual battery capacity is mostly just guessing. There's a few things we can do to try to get the BMS to recalibrate its estimate, but -- it's all still an estimate.
What happened at 4800 miles? Was that a blue snowflake day? If so, seems to imply that the data is temp-related? Anyhow, the charge to 90% only helps with cell imbalance. If charging to 90% doesn't seem to have changed anything, then perhaps the problem is just BMS drift, and not any real loss of capacity. What's your normal charge routine? There doesn't seem to be any rhyme or reason why some people have issues and others don't. People with perfect range, some charge to 90% everyday, and some charge to 60%. The only thing I'd do is change up whatever you're doing, and hope as the temps warm, that the BMS drift, starts to drift up.
I was keeping it at 80% plugging in every day. I rarely drove it any day monday-friday. It would sit at 80%
You're in Massachusetts, I'm in Maine. We face similar ambient conditions. I've looked at your date from August to March, and matched it with my data in blue. Notice the big drop. That was a series of blue snowflake days for me when the temps hit 15F and below. Ours match. Also notice the general shape of our curves. The same. I've overlaid temp data on my chart, in red. Notice how well the rated range correlates with the temp. If you ever have doubts about your rated range, just use the data from the car, by toggling the display between miles and SOC, then do the math. When I do that, I always get between 308 and 312 miles. The data from Stats, in my case, is wrong, because it's using the wrong SOC api, "usable SOC". The car uses the other one.
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Some 3rdparty apps, like Stats and apparently TeslaFi, use the SOC api that is temp-dependent. The car itself uses the other SOC api. Why? dunno. And, if you want to see a whole year's worth of temp related rated range, here's my full chart. August 2019 to now, is only the rightmost 1/3rd. As you can see, I got my car in December of 2018, rated range low, then Summer 2019, rated range 310miles, then Winter 2019, rated range drops, but you can see, it's now creeping back up. It's totally temp-dependent:
This is marginally better for the battery, but worse for BMS drift. I suspected that you were doing this (most people who have teslafi have done tons of reading on this forum and the general guidance here is that its "best" for the battery to keep it at 80% instead of 90%.
This IS marginally better, but we dont know how much. Conversely, there is also some thinking that the voltage between 30% and 80% looks the same to the BMS and only charging above 80% allows the BMS to start to balance. I have also seem threads where the pack balances SLOWLY, over time, while plugged in and set to 90%.
Since you dont drive much you are a prime candidate to test this (and remember I keep my car at 90% at all times so its not like I am telling you to be some out of box guinea pig). Set it to 90% and leave it there. Plug it in every time your car is in the garage (dont run it down, and charge it back up, dont charge it sometimes to 90% for like a week, get frustrated that nothing is changing, and then change).
Set it to 90% and leave it there for like a month. Drive it whenever you drive it, but leave it set to 90% and let it charge and top up back to 90%. Start this today, and see if by May 1st you havent gained some of that mileage back.
I'll give it a shot and see what happens. Just took the car out for a 32 mile drive with the fam just to get out of the house and see the world. Unfortunately I do not have a garage but I have a wall charger outside so it's plugged back in to 90%. We will see how it goes.
AlanSubie4Life
Efficiency Obsessed Member
It is interesting. Ever since the Great American Shutdown started, I have left my car plugged in at 90%. And I gained back a few miles (went from 300 to 304 at a true 100% charge). So going weeks without using the car did seem to do something. It's also a bit warmer, etc. So no idea whether it is just a transient thing or semi-permanent.
Anyway, 1kWh more energy is not nothing. Not huge - probably just 1/4 of my capacity loss or so, but still significant.
I do use percentage. I made sure I clarified that in my first post to avoid this.just to add - you really will feel better to set the car on percentage instead of range.
When driving use the range estimator if you need the safety net of reassurance that you will make it there
I still prefer miles on the display because 1) it is more granular and 2) it at least tells me what the car thinks it has in terms of capacity. I can charge my old smartwatch to 100% too but that doesn't mean it's going to stay on for more than 30 minutes. Let's not derail though
just so you all know, there is some data about how the BMS works in the tesla service manual. it's pretty clear, and with SMT, you can look at max/min cell group imbalance.
If you have a cell imbalance above .005v, the BMS does enable top balancing of the pack above 85% SOC, and the service manual does recommend to leave the car at or above 85% to enable top balancing of the pack.
doing this long term, and always charging to 90% is not the best way to manage the battery life, it's still a lithium ion battery after all, and degrades faster at elevated voltage, especially at higher temperature.
The way I'm planning to manage this is to monitor cell imbalance with tesLAX/ScanMyTesla for the min/max brick voltage and if it goes over .5mV, then I may balance the pack by charging over 90% for a day or so. I think the service manual indicated that 24 hours of pack balancing can reduce imbalance by .1mV, but would need to verity.
If required I could copy/paste the BMS information from the service manual to settle all of this nonsense about how the damn pack works.
If you have a cell imbalance above .005v, the BMS does enable top balancing of the pack above 85% SOC, and the service manual does recommend to leave the car at or above 85% to enable top balancing of the pack.
doing this long term, and always charging to 90% is not the best way to manage the battery life, it's still a lithium ion battery after all, and degrades faster at elevated voltage, especially at higher temperature.
The way I'm planning to manage this is to monitor cell imbalance with tesLAX/ScanMyTesla for the min/max brick voltage and if it goes over .5mV, then I may balance the pack by charging over 90% for a day or so. I think the service manual indicated that 24 hours of pack balancing can reduce imbalance by .1mV, but would need to verity.
If required I could copy/paste the BMS information from the service manual to settle all of this nonsense about how the damn pack works.
It’s in the Theory of Operation guide too, and everything you’ve said is accurate.
I’m still in the “90% and forget about it” camp because that theoretical difference between holding at 80% and 90% is so minimal over the long haul, it’s not worth my brain cell power to think about. I just get in the car and go. Don’t usually bump against the high end of the range on my trips anyway, so it’s all academic for me anyway.
rincewind
Member
^^^^^ This. I do the same. I've had the car for 5,000 miles now and have never once thought for more than a few seconds about range. On the few road trips I've done, I've always planned the appropriate charging stops and don't then worry about it. 90%+ of my driving trips are short journeys of less than 50 miles. I do a 300 miler once a month approx. Always charge to 90% at home, I have the display set to %age and don't give it any thought space. Just enjoy the car.
hill
high fiber member
V3 charging is nice - right now . . . but once the max voltage / charge speed death knell algorithm goes off - it will likely feel much worse than it does from those experiencing it from the old 85-90kWh battery pack owner's POV.I'm actually worse off than you, so at least you're not alone! A little over 6 months of ownership, 7200 miles, range @ 100% is estimated at 289. Tired all the usual maneuvers to recalibrate, with no benefit. Just slow and steady degradation. Supposedly it plateaus at some point, but haven't seen any evidence of it yet
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I'll try to keep this short and simple.
I bought my car in September. I charge to 100% for longer trips about once a month. About 1,000 miles in my full charge was showing around 294. I wasn't happy, but based on what I read in these forums it was normal. I regularly charge to 90% and let it drop to 30-40. Not because of a scientific formula. It's just a comfortable routine that I got into.
By Christmas it was up to 308 and has remained there since.
Go out for a drive when your 100 percent charge shows 290's. You'll get the expected 300 miles if you drive efficiently. Stated range is just stated range. Ballpark estimate.
I bought my car in September. I charge to 100% for longer trips about once a month. About 1,000 miles in my full charge was showing around 294. I wasn't happy, but based on what I read in these forums it was normal. I regularly charge to 90% and let it drop to 30-40. Not because of a scientific formula. It's just a comfortable routine that I got into.
By Christmas it was up to 308 and has remained there since.
Go out for a drive when your 100 percent charge shows 290's. You'll get the expected 300 miles if you drive efficiently. Stated range is just stated range. Ballpark estimate.
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