How I Recovered Half of my Battery's Lost Capacity

[AlanSubie4Life]

But maybe the cellular connection is not stable and that is causing the Teslamate graph showing the many online/sleep cycles

Yeah, the car does not keep a record of what it has been doing (that is accessible to API anyway), AFAIK. I’d just look at the proxy for a log in the car on the new energy screen, observed over long intervals. If the car is sleeping reliably you’ll have very low losses tabulated for Park. To avoid confusion maybe ignore the first 5-10 hours (look at where it is at after 5-10 hours and then do deltas from there).

The 12V monitor is great though. Very unambiguous - and it DOES have a memory (30 days or so and the full historical record is kept in the phone assuming you check it more than once every 30 days - or set it up to automatically download when in range).

 

[**BatteryLow**]

Yeah, the car does not keep a record of what it has been doing (that is accessible to API anyway), AFAIK. I’d just look at the proxy for a log in the car on the new energy screen, observed over long intervals. If the car is sleeping reliably you’ll have very low losses tabulated for Park. To avoid confusion maybe ignore the first 5-10 hours (look at where it is at after 5-10 hours and then do deltas from there).

The 12V monitor is great though. Very unambiguous - and it DOES have a memory (30 days or so and the full historical record is kept in the phone assuming you check it more than once every 30 days - or set it up to automatically download when in range).

Is the 12V monitor in the energy screen? Or is that the cheap 12V monitor you were referring to in your previous post?

 

[Flybyglass]

Is the 12V monitor in the energy screen? Or is that the cheap 12V monitor you were referring to in your previous post?

Try this. You can read it without waking car.

Amazon.com

 

[AlanSubie4Life]

Is the 12V monitor in the energy screen? Or is that the cheap 12V monitor you were referring to in your previous post?

There’s the monitor/logging on the screen (can definitely use this, just requires some care to eliminate transient effects). And then there is the actual 12V monitor device (many near identical devices available, like the above). Either one is fine. Whatever works best for you.

 

[johnny_cakes]

Are people still trying this technique proposed by OP and does it still work?

 

[mcbanan]

It works. I bought a 2019 LR AWD last summer, and the estimated range showed 460 km/ 285 miles. A year later it says 480km/ 298 miles. I also suggest following @AAKEE ´s advices on charging limits etc. in the range loss over time thread.

 

[Dvdarb]

You also have a new “Reset SoC” button in service mode. Didn’t tried it myself but I assume it will delete all statistic data on OCV.

 

[johnny_cakes]

It works. I bought a 2019 LR AWD last summer, and the estimated range showed 460 km/ 285 miles. A year later it says 480km/ 298 miles. I also suggest following @AAKEE ´s advices on charging limits etc. in the range loss over time thread.

Thanks for sharing. Curious what your charging habits are to balance the low SoC strategy for battery health and letting the car sleep at different SoC for BMS calibration.

 

[mcbanan]

Thanks for sharing. Curious what your charging habits are to balance the low SoC strategy for battery health and letting the car sleep at different SoC for BMS calibration.

Well we have two electric cars and one charger, so it kinda works itself out.

I charge only to 55% unless i need more for a roadtrip.

And since the other car needs the charger more often than the Tesla, it usually sits with 5-55% SOC.

Before I go on a roadtrip I ramp up the charge over a couple of days so that the BMS gets readings between 55-90%. And right before i leave I charge all the way to 100%.

 

[Paige111]

Thank you for this explanation, hopefully this is the issue with my battery. My commute has been shorter the past 10 months, yet my battery has drained > twice as fast than when my commute was approx 1hr. Plus I always have sentry on. Will try to charge my car @ various levels, hopefully this will fix range. Mine dropped 36 mls with 16.5K mls/18 months, so hopefully range will improve, thanks

 

[johnny_cakes]

Before I go on a roadtrip I ramp up the charge over a couple of days so that the BMS gets readings between 55-90%. And right before i leave I charge all the way to 100%.

What changes do you notice when you ramp up the charge over a couple of days? Does the BMS start reporting a higher max range? I may try this if it only takes a couple of days.

 

[AAKEE]

What changes do you notice when you ramp up the charge over a couple of days? Does the BMS start reporting a higher max range? I may try this if it only takes a couple of days.

I do not do like that (I know the question was for @mcbanan), I use low SOC as much as possible and charge once to the needed SOC shortly before the drive.

Yesterday we had a plan to leave for my mother in law, a 250km + drive, and needed to drive some at artival as well.
I did a calculation by mental arithmetic about when to set ut to charge, in the end it ended up finisched 30 min before we left.

Appearently it works quite well:

 

[M1NA]

So long story short, turn off sentry mode so the car can sleep for 6+ hours undisturbed while at work or at home overnight, so the BMS can sample the voltage over a range of SOC's, then charge it to 95% a few times and briefly to 100%.

Should we do this with 2023 model 3 as well?

 

[Perscitus]

You also have a new “Reset SoC” button in service mode. Didn’t tried it myself but I assume it will delete all statistic data on OCV.

Ah yes the PROC_HVBMS_X_RESET-SOC proc.

HVB contactors must be open for this to work, I havent found a way to keep the car powered on with them in an open state and with the car in service mode with gateway unlocked... dont want to risk bricking anything or having all powered by the LVB.

Sadly the service manual talks nothing of this recent addition to the service mode GUI.

 

[AAKEE]

Ah yes the PROC_HVBMS_X_RESET-SOC proc.

HVB contactors must be open for this to work, I havent found a way to keep the car powered on with them in an open state and with the car in service mode with gateway unlocked... dont want to risk bricking anything or having all powered by the LVB.

Sadly the service manual talks nothing of this recent addition to the service mode GUI.

View attachment 935145

Also, the SOC only will be reset As it seems. Not the calculations for nominal full pack.

 

[johnny_cakes]

I do not do like that (I know the question was for @mcbanan), I use low SOC as much as possible and charge once to the needed SOC shortly before the drive.

Yesterday we had a plan to leave for my mother in law, a 250km + drive, and needed to drive some at artival as well.
I did a calculation by mental arithmetic about when to set ut to charge, in the end it ended up finisched 30 min before we left.

View attachment 935078

Appearently it works quite well:
View attachment 935082

Yes, I'm a big fan of your strategy and I've been advocating it. It sounds like @mcbanan is a fan as well but with a little bit of BMS tuning here and there, so I was trying to get more information about that.

 

[mcbanan]

Yes, I'm a big fan of your strategy and I've been advocating it. It sounds like @mcbanan is a fan as well but with a little bit of BMS tuning here and there, so I was trying to get more information about that.

Like I said its just so that the BMS gets data from 55% and up, once in a while, since I rarely charge above that. Probably not necessary

 

[Bubbatech]

I have a Model 3 LR, delivered during early 2020. It has about 30,000 miles and, to date, has been absolutely trouble free. Since the beginning, I have tended to keep the charge limit between 70-90% and very rarely let the charge state fall below 50%. My commute round trip is 19 miles with an altitude change of 400ft, so the average round trip uses approximately 6%. By April of this year, my calculated maximum range was 262 miles, which I thought was relatively poor, approaching SR+ territory. I pinged Tesla service, which responded, ultimately saying (paraphrased) "There is nothing you can do. It will continue to drop and when it reaches the threshold of 70% of rated range, we will take care of it". I did not believe him. Given the way I was charging the car and that I am a "light" driver (bordering on driving like an old fart), I doubted that I was looking at a hardware issue. I reasoned that the BMS has to use some combination of regression, a moving average, and God knows what else to come up with a value, with general order number one being "thou shalt not strand the driver by estimating more range than is available". So I decided to change my charging regime by simply using the middle 50%, running from 75% to 25% (ish) figuring that this would provide a wider range of data points for calculation. This meant not always plugging the car in once the state reached below 50%. With this regime, the calculated range steadily increased after that and is now at 296 - 299 miles. I did not expect that large a change figuring, if I was right, that it might go up as high as 285 or so, but it is still continuing to creep up. I believe the rated range a the time I purchased the car was about 321 (?) miles. If so, then the difference between the rating and the current estimate is 7-8%, well within the expected decrease that I would see at 3 years or so. It has been fun gaming the estimate to see if I could change it. I did not expect it to be so simple and effective. I have no idea how generally applicable this strategy might be.

 

[KenC]

What made you decide to never run it below 50% to begin with?

 

[NeverGoingBack]

Try charging it up to 100%. I think that is one of the keys to BMS calibration.

I’ve seen my estimated full charge range jump (up) significantly after doing that.