Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

[KenC]

Hey guys, No offense intended but are there any real battery engineers here? I am not but I have been driving EVs for 15 years and have read a lot. Tesla may have cutting edge-state-of-the-art tech that makes my past observations obsolete (?) As I understand it; it is a challenge for the computer to calculate exact range/SOC of a battery especially while sitting--under load is somewhat easier.

Variable 1--Somebody just now = page 56 brought up seasonal temperatures affecting 100% calculations.
Variable 2--I think even Tesla confirmed the standard technique of now and then draining a pack then charging to 100% to recalibrate the battery and the SOC computer.

If these two things are true they could explain some of our discrepancies--no?

2018 M3 Dual

Just to clarify Variable 1, if you were referring to my post. I was talking about 3rd-party apps that use the SOC api that is temperature dependent. There's another SOC api that is not temp dependent, and that's the one the car actually uses.

Having said that, it's thought that temperature change, contributes to BMS drift, but that's different than what my post was referring to. Mine is about the SOC api that 3rd party apps seem to like to use. Why? Dunno. I've told the Stats developer, but he doesn't seem to get it.

 

[ran349]

Just to clarify Variable 1, if you were referring to my post. I was talking about 3rd-party apps that use the SOC api that is temperature dependent. There's another SOC api that is not temp dependent, and that's the one the car actually uses.

Having said that, it's thought that temperature change, contributes to BMS drift, but that's different than what my post was referring to. Mine is about the SOC api that 3rd party apps seem to like to use. Why? Dunno. I've told the Stats developer, but he doesn't seem to get it.

It's interesting how the different developers for these 3rd party apps look at things. I informed the developer of the api app I use, Remote Tesla, about the discrepancy with the SOC percent reading, and he changed it on the next update, so now it always matches the car reading.

Why not use what the car uses? That is what I would ask the Stats developer.

 

[KenC]

It's interesting how the different developers for these 3rd party apps look at things. I informed the developer of the api app I use, Remote Tesla, about the discrepancy with the SOC percent reading, and he changed it on the next update, so now it always matches the car reading.

Why not use what the car uses? That is what I would ask the Stats developer.

LOL, I posted the last graph with explanation to the developer's twitter feed, a week ago, after the developer and Stats users were posting charts of their Rated Range increasing. Of course, it's due to the temperature rising, so I posted my last graph to show them. Crickets.

 

[mrgoogle]

I have the Model 3 SR (not plus), so I have an EPA of 220 miles- and what I’ve looked up online-50kwh battery. I picked it up in March, and I have noticed I’m not getting anywhere near the EPA (or whats stated when charged to 100% - 219miles)

I read somewhere charging it to 100% once might help and ‘reset’ the battery, so I did that two days ago. I traveled 141 miles and it ran me down to 12%. Details from the car provide I’m doing 229 Wh/mi and used 32kWh....doesn’t seem right that I came down to 12% at those stats. I used sentry mode for 2 hours.

So what amount of miles do you get with 18aero set in the car?

I managed to loose the sr+ lottery, ours is -12% and I only get 208-211 miles best case (so warm battery! Even when Preheated for hours) I am still pissed Tesla just doesn’t do anything about it.

I take great care of the car but -12% is a big noticeable loss, a drive to my parents is when I always miss a few % to make a round trip because of it, really annoying.

SR non plus got better range...

 

[VT_EE]

22-month old Model 3 LR RWD with 32000 miles. I've gained 6-7 miles of range in the last couple of months which may be the result of temperature or a few charging sessions to 90%. I charged to 100% today for the first time in 6+ months, and the car estimatied 310miles of range. That is less than 5% loss after almost 2 years. Not bad IMO.

 

[pdx_m3s]

After exactly 1 year and 5,300 miles, sitting at exactly 5% degradation (228 miles @ 90%). I've never supercharged or charged the car to 100%, because I haven't needed to.

 

[dmurphy]

16,288 miles; 13.5 month old Model 3 LR AWD. "Set it and forget it" at 90% since day one. If it's home, it's charging.

90% charge: 275 miles
100% charge: 306 miles
Was 309 miles at new.

I don't do a damn thing to "manage" my charging except plug it in. Set and forget.

 

[MarcG]

16,288 miles; 13.5 month old Model 3 LR AWD. "Set it and forget it" at 90% since day one. If it's home, it's charging.

90% charge: 275 miles
100% charge: 306 miles
Was 309 miles at new.

I don't do a damn thing to "manage" my charging except plug it in. Set and forget.

Impressive. How much, if any, supercharging (or DC charging) have you done?

 

[dmurphy]

Impressive. How much, if any, supercharging (or DC charging) have you done?

Not much. No DC other than Superchargers, and even that, fairly minimal. Hard to total based on minutes, but here's all the Supercharging I've ever done:

4/20/19: 30 minutes
5/3/19: 47 minutes
5/4/19: 9 minutes
5/5/19: 64 minutes (2 stops)
8/1/19: 44 minutes
12/7/19: 7 kWh
5/31/20: 24 kWh

Now, that said - I was hovering at around 302mi at full (which is perfectly acceptable as well) - but after that 5/31/2020 Supercharging session, it's showing 306. Wonder if the pre-warming got the BMS back into some calibration or another?

Maybe an occasional warming/supercharging session exercises the battery in a way the usual charge-drive cycle doesn't?

 

[MarcG]

I doubt pre-SC warming does anything to calibrate. Charging to close to 100% usually does, but it's not great for the battery as it ironically creates more degradation.

Supercharging more often than not does accelerate degradation, so your low SC usage correlates to your low degradation. My car has similar age and mileage to yours and is showing around 299 miles full (was 310 new), but have supercharged a lot (about 35% of my total charging).

 

[v8eater]

2019 LR AWD 18 Aero without covers 22,600 as of this morning.

Charged to 80% most of the time. Daily use gets it down to about 59%. Charged to 100% 7 times.


Range @ 100% charge is now 271.

The range dropped the first time from 308 to 297 Dec 24th when I installed 2019.40.2.1. Range dropped 295 to 282 on 27 March when I installed 2020.12. Range dropped again from 282 to 271 on 2 June when I installed 2020.16.2.1

What I hope is happening is a combination of two things, first charging the majority of time to 80% didn't allow the pack to balance. Second, because of an unbalanced pack, and new software for the BMS, my car now thinks it only has 271 miles of range @ 100%

I'm trying not to worry about this and have started charging the car to 90% daily. Moving cross country in three weeks so 3k miles of SC should help the BMS figure things out.

 

[ElectrekPanda]

According to my TeslaFi report, battery is improving in the last 6 months. I don't know what is affecting it. But I like it - it is back to where it was in January. Overall, just about 3% down from rated range after 16K miles of driving.

 

[KenC]

According to my TeslaFi report, battery is improving in the last 6 months. I don't know what is affecting it. But I like it - it is back to where it was in January. Overall, just about 3% down from rated range after 16K miles of driving.
View attachment 548258

Looks totally seasonal. My understanding is that TeslaFi uses the temp-dependent SOC api, just like Stats. So, within any degradation, and BMS drift, you'll also get temperature effects. Look at my Stats data, graphed with temperature, to see how closely my rated range matches temp:

 

[MickyMunch]

P3- with 34k miles. Bought in August 2019. Always use aero covers. Charge to 90% whenever home. Charged to 100% a handful of times, ~95% a couple dozen times. Quite a bit of supercharging, probably 12k miles worth. Range when new 309 miles. Now 291 miles. Average consumption 267Wh/mi mostly freeway driving and lots of cold winter in WI and MN. Since summer (4500 miles) I've averaged 249 Wh/mi.

Original tires are to the wear bars. Putting on Continental DWS 06s later this week which will affect consumption at least for 1k miles.

 

[dmurphy]

Looks totally seasonal. My understanding is that TeslaFi uses the temp-dependent SOC api, just like Stats. So, within any degradation, and BMS drift, you'll also get temperature effects. Look at my Stats data, graphed with temperature, to see how closely my rated range matches temp:

I agree. As it continues to warm up here in the Northeast, my expected range continues to climb.

After almost 17k miles, I’m basically back at brand-new capacity. With no overthinking - pull in the driveway, plug it in. That’s it.

 

[Celledral]

My SR+ has been going down during the winter, mind you this is in SoCal, so it's basically spring for some areas. I thought I would get a few miles back during the hotter season, but doesn' seem like it's happening. Been going down nonstop every week. Currently sitting at 218miles from the supposed 240, nearly a 10% degradation in a year with 19,000 miles. I even did a full 100% run down to 7% in a single trip and was only able to burn through 42kWh, which means I'm at a 6kwh battery degradation with buffer accounted for. Tesla says it's fine and closed my case after I shared with them my kWh usage.

 

[insaneoctane]

Looks totally seasonal. My understanding is that TeslaFi uses the temp-dependent SOC api, just like Stats. So, within any degradation, and BMS drift, you'll also get temperature effects. Look at my Stats data, graphed with temperature, to see how closely my rated range matches temp:
View attachment 548318

I manually overlayed temperature onto my data. It doesn't match as well as yours, but I'm definitely sold that temp is the main driver to predicted range and thus, 'short-term degradation'.

BTW, this chart covers ~0 mi on left and 50K on right
The big grey box is some missing data in my collection.

 

[KenC]

I manually overlayed temperature onto my data. It doesn't match as well as yours, but I'm definitely sold that temp is the main driver to predicted range and thus, 'short-term degradation'.
View attachment 550140

BTW, this chart covers ~0 mi on left and 50K on right
The big grey box is some missing data in my collection.

And, you're in SoCal, so cold temps are much, much less than in New England, and yet your rated range data still shows it's affected by seasonal temp swings.

 

[1.21GW]

I manually overlayed temperature onto my data. It doesn't match as well as yours, but I'm definitely sold that temp is the main driver to predicted range and thus, 'short-term degradation'.
View attachment 550140

BTW, this chart covers ~0 mi on left and 50K on right
The big grey box is some missing data in my collection.

Are you kidding me... the coldest it gets by you is about 60 degrees??

 

[insaneoctane]

Are you kidding me... the coldest it gets by you is about 60 degrees??

Not quite. This is daily high temp, so it get's colder at night/morning....