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Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health
- Thread starter KK_RedM3
- Start date
voip-ninja
Give me some sugar baby
Ok so I have not gotten any further follow up from the SA of my local S.C. (I asked about a BMS reset a few days ago) but something odd did happen today.
I did a much longer drive than I normally do, traveling about 140 miles round trip with several hours at my destination. It was mostly highway driving at 70-75 MPH and the car reported energy efficiency of about 250 kWh/m for the trip.
I left my house with 89% battery and returned with it just ticking down to 34%. I remember this because on the way home I kept seeing the estimated range at destination flip between 34 and 35%.
Now here’s the interesting/odd thing. I had to depart again before charging the battery. I got into the car after about 40 minutes and perplexingly the car showed 39% battery. It soon ticked down to 38% but lasted to 37% after my 7-8 mile errand was run.
strange.....
car charging now, it’s been showing 260 miles at 90% so I will check when charging is done and see what is being displayed.
I did a much longer drive than I normally do, traveling about 140 miles round trip with several hours at my destination. It was mostly highway driving at 70-75 MPH and the car reported energy efficiency of about 250 kWh/m for the trip.
I left my house with 89% battery and returned with it just ticking down to 34%. I remember this because on the way home I kept seeing the estimated range at destination flip between 34 and 35%.
Now here’s the interesting/odd thing. I had to depart again before charging the battery. I got into the car after about 40 minutes and perplexingly the car showed 39% battery. It soon ticked down to 38% but lasted to 37% after my 7-8 mile errand was run.
strange.....
car charging now, it’s been showing 260 miles at 90% so I will check when charging is done and see what is being displayed.
SammichLover
Banned
A phantom 5% of capacity popping back in like that would be somewhat inline with needing to take the battery down low to recalibrate the BMS for the battery.
So I hadn't taken my battery back to 100% for quite some time, and haven't had the display on Distance for about as long. I think I've not taken it about 90% SOC since July towards the the end of my Canada trip. I've only put on about 7K miles since then. I happened to recharge to 100% two days ago, I was planning on doing a lot of driving over the day, and out of curiosity switched to Distance (it had been holding just under 300 miles for quite some time) before I saw any of this and nearly dropped a brink when it said 282 miles.
To hang some numbers on that, I was still at approximately 298 mi for 100% SOC (where it had plateaued since about 15K miles) at about 38K miles and now just short of 45K miles it has fallen off a cliff. That's definitely something other than normal degradation going on.
So I guess I'm going to be watching this all rather closely.
voip-ninja
Give me some sugar baby
mikeshyu
Member
Mine at 90% is at 262. Took delivery 09/2018. At that time 90% was around 280ish.
Yup to the last three posts. Mine is a year-old Sept car too. Of course we all used to show about 280 miles at 90%.... and now 260 is sounding pretty good to me! I just finished charging to 90% and am staring at 252 estimated miles. I have lots of driving planned for this weekend, so I might as well do at least one 100% charge, and a good drain. Really sucks that this would be required though. Degrading the battery in purpose in order to get the CAC back on track is troubling.
... Then don't do it.
It's reporting a conservative (safe) estimate. Eventually, you may need a long discharge cycle naturally, and it will adjust itself. Why "degrade the battery" just to make the estimate less conservative?
And yes, it will still be an estimate, not your "true" range or "correct" range. It's ALWAYS an estimate, and will be different from reality depending on how and where you drive.
There is a quite frustrating but fundamental misunderstanding within the ownership community on how Tesla calculates range, (Instant, Average, etc.) While re-calibrating and 'balancing' the battery pack for sure has its merits, everyone NEED's to stop living by the range counter like it's the oxygen you need to breathe. This number is FAR from exact. It's a GUESTIMATE based on how you drive, recent and long term, weather, etc. Just like a good ol' gas car, the HARDER you drive, the LESS range you will have, and this among MANY other factors can effect your cars range GUESTIMATE. Yes, batteries degrade, but EVERYONE puts different loads on their car. Everyone WEIGHS different amounts. Some people consistently drive with 4 people in the car, some people never have more than two. Everyone needs to CHILLLLLLLLLLLLL
boiler81
Member
Or maybe Tesla needs to provide owners an quarterly battery health report since they are collecting all our data, and be transparent when they degrade the usable battery capacity to owners vehicles via OTA updates.
Stellavator
Member
You are totally misunderstanding the issue. Folks are not talking about the actual range you get based on driving habits. Folks here are talking about the rated miles, which is a direct calculation from battery kWh based on the 240 Wh/mi. When that decreases, it implies that the battery actually is losing capacity. That is the concern. And I agree that it would all be a lot easier if Tesla would simply issue an official explanation, rather than leaving everyone to the forums for more and more frustrating anecdote and conjecture.
But dude, you are far too angry about this. If you are so troubled by the conversation, then please, stop reading it.
yerEVan
Active Member
I think when looking at the battery percentage instead of miles, it would be cool to have a tenth decimal. If it shows 233 miles instead of rounding it to 230 then it would be cool to have 82.0% or 82.9% (instead of just 82%) so I know I have 3 more miles (.9% equals ~3 miles) compared to when it would show the old way.
If it shows miles and not “rounded miles by 3 miles”, then a tenth of a percent would equal that same measure.
If it shows miles and not “rounded miles by 3 miles”, then a tenth of a percent would equal that same measure.
Good point. And while we are asking for relatively simple updates to the display... why must we choose to show one or the other: SOC % or the estimated range? Why not have them both shown without needing to dig into the menu to change them? Or at least, why not just tap that number being displayed and have it cycle to the other (currently tapping it takes you to the charge screen which isn't quite as useful since you have at least two other easy ways to get to that screen.)
No.... this is still simply false.... That's exactly what folks think they are talking about, albeit incorrectly. kWh/mi is still a calculation. Every single person's kWh/mi is variably different. This is not a concrete, finite, static, precise number. Yes, battery degradation over time is a real thing. I think we all understand that. But again, what your car displays to you as range is an estimate which is variable to a multitude of external factors ie: vehicle load, terrain, environmental factors, temperature, passenger/driver weight. kWh/mi is a statistic that changes and evolves. If yours is decreasing, this is not wholly due simply to degradation. You also have to take into all of the other factors, exampled above, into account and the car averages out over time and settles into you as a user. Hence why some people have little to no degradation, and some people have more! Some people have a lower kWh/mi value, and some people have higher! I am not the angry one, it seems like all of you fussing around about your kWh/mi statistics are the angry ones!
I am glad that you don't have the issue being discussed, or at least are not bothered by it. If the "fussing" from others is not useful to you, I hope you can quietly allow those of us who DO find it useful to use this thread for the purpose of discussion of the topic.
yerEVan
Active Member
I 2nd this. If there is a pattern of excessive degradation of the batteries inside the pack, and people here can discuss it, then I find this thread very useful to monitor. Since degradation is a real thing and if people are finding that their battery is only giving them 91% of charge at 100% charging after less than a year, then that is a legit concern, and I’m learning from people here on this thread.
You have the ability to just simply shut the soundproof door that leads to this thread/room, and leave us all “cry” in peace, I guess.
I wonder if the 3 battery packs are significantly different from X or S, in that The degradation or calculation of rated range/percentage is more affected with the 3 batteries. I have an X that is slightly older than my 2018 3, and it has a 4 mile loss of range (which is pretty negligible), but have 18 mile loss of range on the 3 (292 miles at 100%).
My 3 started to drop off instantly at around 6500 miles. But honestly, i don’t even have that many miles on the Model X so i guess i need to wait and see.
Maybe a subscription service... 99/year seems reasonable for that kind of service.... but you have no real evidence of the latter
This is fundamentally inaccurate. The rated range that is displayed on the left side of the screen in the Model 3 is just that: rated range. It's based on a fix kWh/m which may or may not apply to everyone in every circumstance but it is not adjusted for variances in average kwh/m consumption. This is how Tesla has always measured it and it's frankly misleading at best because you're right: most people don't see that because of cold weather, because of wider tires, because of driving habits, etc.
My old i3 displayed the range correctly and would always fluctuate based on an average of driving habits and recent consumption. I never saw the full range on that car because I drove the car aggressively and it adjusted it's ranged based on that driving.
To be clear though, Tesla does not do that. Tesla bases their range on a specific kWh/m rating and times that by the available capacity in the battery to come up with the estimated range. Example: I drive the snot out of my car but still charge fully to 325 miles.
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