-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Set Charging Percentage Wrong
- Thread starter Resist
- Start date
bo3bdar
Member
How about just set it from the car what you need daily and foget about it?
Because it's a concern if I charge to 100%. Is it right or not? Is it going to overcharge now? I don't get you guys making excuses for all these bugs and flaws. The idea is that the car is supposed to get better over time.
It used to be spot on every charge. I set to stop at 80%. When I see it the next day, it's 80%. Just tested this again, and have it set to stop at 80%. Notification in phone app said- stopped at 80%. Later today I checked it and it was 84%. This is using the 120V charger, so it's not exactly pushing the battery temperature or charging very hard.
When I charged using a Supercharger and drove 2 miles home- the charge rate it showed when I got home was the same as the next day. Doesn't seem heat related.
Last edited:
bo3bdar
Member
Off the top of my head, without checking any notes:
1) This thread- Charging is no longer consistent. Reported charge is always high the next door. Being off by 5% is a pretty big miss for charging a battery.
2) Opening the users manual crashes the head unit. Every time. Some people get max AC when it happens.
3) Head unit crashes on occasion while driving. This is totally unacceptable. Geeks don't care, normal people no longer trust the car.
4) Display map stuck for an entire drive. Showed car off in funny space, the middle of the bay. Not updating.
5) Phone UI stuck on for an entire drive. My phone calling... itself. Could not dismiss, could not cancel. Came back up after reboot.
6) Visualizations are totally useless, and now suck up a full 1/3 of my screen. Even when parked the map and browser are smaller now.
7) Visualizations are blinking and distracting in my peripheral vision. No way to turn it off, hide it, move it, shrink it. Zero options.
8) Speed limit indicators and speedometer are mixed up visually and just a mess now. Centered speedo made sense on the 'car' section.
9) Drive indicator on left edge is now small and grey on grey. Low contrast UI fad is far worse than it was.
10) Small fonts in the UI. So small I can't read them without reading glasses. Why the design hate for people without perfect vision?
11) Album Art for USB music no longer works at all.
12) Music used to pick up where it left off, mid song. For USB music this no longer works.
13) After an update, my passenger seat was folded completely flat crushing the back seat that was lowered.
14) Latest update to my car- failed. Tesla said it was an error on their end.
15) Sentry Mode viewer stopped responding to taps on the notification banner. Works at home, but not when out.
That's literally off the top of my head. I can find another 15 examples if I check my notes. There has never been a single drive I've made where the car didn't do something funny/unexpected. The software is glitchy and flaky and unpredictable. The designers could give a sh*t if the user experience has been degraded. The software is a critical aspect of the Tesla experience, and I've lost confidence in their ability to write good software.
The car is fun as hell to drive, but their software is just sad. Yeah, I'm a software dev, and my expectations are too high. Sue me.
Last edited:
Most on your list are none existing problems on our 2 year old M3. If you have so many freeze ups I would schedule Service visit! Other things on your list your opinion and doesn’t mean anything wrong with the car. LoL Tesla is Literally leader in car software I don’t know what are you talking about.
Last edited:
Exactly. People are just anal-retentive because they see a number.
No one cares when the fuel gauge goes to E but you still have like 2 gallons in the tank. Now the percentage meter is off one 1%, people lose their minds.
Last night I came home from a trip and my battery was at 26%, I set my Model 3 with firmware 2021.24.3 to stop charging at 50%. Today the battery was at 64% and still charging before I stopped it. What the heck?!
Has anyone else experienced this? I don't know if my BMS is out to lunch or what, but recently it never stops charging at what I set it to and certainly never kept charging this far past what I set it at.
Has anyone else experienced this? I don't know if my BMS is out to lunch or what, but recently it never stops charging at what I set it to and certainly never kept charging this far past what I set it at.
Last edited:
Tam
Well-Known Member
If you faithfully set and charge daily at 90%, the frequency of overshooting the target won't happen as much and is not as drastic.
I think BMS does the calculation based on the above parameter. If you deviate from that, the accuracy of the BMS might drift as in your case, to a giant 14% difference.
Your old number of 50% that you thought was 50% but actually, it's 64% that was miscalculated as the old 50%. The new 64% is the new corrected one.
Candleflame
Active Member
the overcharging from i.e. 70% -> 74% is a result of the BMS mapping being (significantly) off. This can happen with software updates but should technically correct itself after a while...
The car will map out a voltage vs watthour curve which it then translates to rated miles. In a brandnew vehicle this should always be correct as the computer already knows how many kwh are in a fresh new pack so there is no calculation involved as such - note that this is not fully true as the car notices a capacity above rated kms but the rated kms are clamped to a limit i.e. 499km regardless of the battery actually having 415km. Once degradation occurs it is up to the car to decide how many kwh or rated kms are in the pack.
The voltage reading is directly related to how many % of charge you have left in your battery, however the % displayed by the cars GUI is directly related to the rated kms/kwh the car thinks it has.
Voltage is tricky to read as the car needs to have no voltage fluctuations for a while so doesnt happen often in park but usually happens after 3h of sleeping. The car does occasionally do take voltage readings though while in park without sleeping. Voltage can of course be read during driving too but noone really knows how often the car actually does it and how it uses the obtained reading to adjust the % charge displayed while driving. The principal issue here is that i.e. flooring the throttle will lead to a large voltage drop but the car will not automatically knock of 10% of the battery and then restore that when lifting off the throttle. We do not that this voltage-drop gets limited at low SOC by the car limiting the power so you cannot undervolt individual cells and cause permanent damage. Once a voltage reading which the car feels is reliable it will update the % displayed on the car. We do know that once a certain LOW voltage is reached the car will shut itself off regardless of how many rated kms/% are left in the car. This usually leads to an immediate update of the % SOC. The best example of this is when old Model S/Xs with crappy batteries were driven down to 30% suddenly the SOC would drop rapidly to 0% in a few kms followed by emergency shutdown. Another example is driving a Model 3 with a warm battery in Alaska down to 6%. The car then cools down which lowers battery voltage especially under load so after 10min outside suddenly it only displays 0-1%.
Rated kms/kwh capacity is something the BMS calculates after a while and re-calculates as necessary. The user can see that info as rated kms. If you were to sneakily remove 100 cells from the car and bypass those the BMS will still show your original rated kms however voltage errors as I have described above will be more and more frequent until the BMS runs a recalibration to change the rated kms. The opposite is also true. People who have had battery pack replacements sometimes still see their old rated km value which obviously doesnt match the massive amounts of available energy so this causes the battery to sluggishly empty when low and undershoot when being charged up but eventually recalibrations will happen to update the voltage table vs the rated range table.
When you have 500km rated range and set your charge slider to 80%/400km the car will charge until the 400 rated kms are reached and then stop doing anything. It now waits for a voltage reading - if this reading i.e. 383.45335V or whatever does not match the 80% on the internal table then it will adjust the % to where it is correct. Can that mean that you are able to charge to 104%? - under normal circumstances the BMS should stop the charge if the cells all go above 4.2V (this can result in the SOC being stuck on 99%) however we do know that fleet Teslas have been able to do exactly that by supercharging from i.e. 5% to 100% without letting the BMS take a voltage reading. With the combination of uncertain discharge %, uncertain recharge %, voltage fluctuations due to fast supercharging and batteries heating up this indeed did lead to batteries being charged to 105% and very reduced lifespans and pack failures.
--
So basically plug your car in every day and charge to 85% or whatever and hopefully after a few weeks your rated range should update itself to match the internal voltage to SOC table.
The car will map out a voltage vs watthour curve which it then translates to rated miles. In a brandnew vehicle this should always be correct as the computer already knows how many kwh are in a fresh new pack so there is no calculation involved as such - note that this is not fully true as the car notices a capacity above rated kms but the rated kms are clamped to a limit i.e. 499km regardless of the battery actually having 415km. Once degradation occurs it is up to the car to decide how many kwh or rated kms are in the pack.
The voltage reading is directly related to how many % of charge you have left in your battery, however the % displayed by the cars GUI is directly related to the rated kms/kwh the car thinks it has.
Voltage is tricky to read as the car needs to have no voltage fluctuations for a while so doesnt happen often in park but usually happens after 3h of sleeping. The car does occasionally do take voltage readings though while in park without sleeping. Voltage can of course be read during driving too but noone really knows how often the car actually does it and how it uses the obtained reading to adjust the % charge displayed while driving. The principal issue here is that i.e. flooring the throttle will lead to a large voltage drop but the car will not automatically knock of 10% of the battery and then restore that when lifting off the throttle. We do not that this voltage-drop gets limited at low SOC by the car limiting the power so you cannot undervolt individual cells and cause permanent damage. Once a voltage reading which the car feels is reliable it will update the % displayed on the car. We do know that once a certain LOW voltage is reached the car will shut itself off regardless of how many rated kms/% are left in the car. This usually leads to an immediate update of the % SOC. The best example of this is when old Model S/Xs with crappy batteries were driven down to 30% suddenly the SOC would drop rapidly to 0% in a few kms followed by emergency shutdown. Another example is driving a Model 3 with a warm battery in Alaska down to 6%. The car then cools down which lowers battery voltage especially under load so after 10min outside suddenly it only displays 0-1%.
Rated kms/kwh capacity is something the BMS calculates after a while and re-calculates as necessary. The user can see that info as rated kms. If you were to sneakily remove 100 cells from the car and bypass those the BMS will still show your original rated kms however voltage errors as I have described above will be more and more frequent until the BMS runs a recalibration to change the rated kms. The opposite is also true. People who have had battery pack replacements sometimes still see their old rated km value which obviously doesnt match the massive amounts of available energy so this causes the battery to sluggishly empty when low and undershoot when being charged up but eventually recalibrations will happen to update the voltage table vs the rated range table.
When you have 500km rated range and set your charge slider to 80%/400km the car will charge until the 400 rated kms are reached and then stop doing anything. It now waits for a voltage reading - if this reading i.e. 383.45335V or whatever does not match the 80% on the internal table then it will adjust the % to where it is correct. Can that mean that you are able to charge to 104%? - under normal circumstances the BMS should stop the charge if the cells all go above 4.2V (this can result in the SOC being stuck on 99%) however we do know that fleet Teslas have been able to do exactly that by supercharging from i.e. 5% to 100% without letting the BMS take a voltage reading. With the combination of uncertain discharge %, uncertain recharge %, voltage fluctuations due to fast supercharging and batteries heating up this indeed did lead to batteries being charged to 105% and very reduced lifespans and pack failures.
--
So basically plug your car in every day and charge to 85% or whatever and hopefully after a few weeks your rated range should update itself to match the internal voltage to SOC table.
The problem with this overshooting thing, is that what if I want to charge to say 90% and it ends up at 100%. It wouldn't be good for my car to be sitting all night at 100%. How am I supposed to trust it to charge correctly now? It never used to do this and it didn't do it last year, but all of sudden this year it went all wacky.
Candleflame
Active Member
Yes thats why when my car sits at 60% all the time i dont suddenly charge to 90%. when i need it i charge to 85% first and then 90% the morning before i leave. The maximum i have ever seen has been 6%. 1 to 2% is common. 4% does happen occasionally.
I've had my MY LR for over 2 months, and I just assumed I was fat-fingering the charge limit setting on the touchscreen. It always seems to stop 1–4% higher than I thought I set it.
I noticed in the phone app that it shows a digital percentage, but the one time I used the phone app to set the percentage (when I forgot to set it before leaving the car), I was in a hurry the next morning and didn't pay attention to where it ended up.
I don't think 80% or 90% is some magic number, and if you exceed that by a few percentages, your battery will be ruined. As others in the thread have explained better than I could, measuring the state of charge cannot be done to pinpoint accuracy. I almost wonder if the newer software updates aren't being more accurate than they previously were. I'm a software developer, too, and I can easily envision that conversation in a planning session.
Engineer: "We can't be sure it's charged exactly to 80%."
Product manager: "Well, since we know the limit they set it to, when it's close, can we just stop charging, and show that limit as the SOC?"
Engineer: "Sure, we can do that."
I noticed in the phone app that it shows a digital percentage, but the one time I used the phone app to set the percentage (when I forgot to set it before leaving the car), I was in a hurry the next morning and didn't pay attention to where it ended up.
I don't think 80% or 90% is some magic number, and if you exceed that by a few percentages, your battery will be ruined. As others in the thread have explained better than I could, measuring the state of charge cannot be done to pinpoint accuracy. I almost wonder if the newer software updates aren't being more accurate than they previously were. I'm a software developer, too, and I can easily envision that conversation in a planning session.
Engineer: "We can't be sure it's charged exactly to 80%."
Product manager: "Well, since we know the limit they set it to, when it's close, can we just stop charging, and show that limit as the SOC?"
Engineer: "Sure, we can do that."
Candleflame
Active Member
Yeah you have had a bms miscalibration which hopefully should be better now. Not clear if software or hardware caused this...
Similar threads
