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

[Remonster]

Hello Everone,

I am somewhat frustrated with my tesla and I need support to understand what I am doing wrong. So I bought a 2020 tesla model 3 standard range plus rear-wheel drive with 5,295 miles.

I supercharged my car to 90%/212 miles. I drove10 miles back home and my charge went down to 81%/193 miles. Why is that? Why is my charge going down so quick?

I already took of cabin overheat protection, sentry mode. I put my car on chill mode. Idk what else to do.

My avr energy is almost 400.

Can someone please support me or give me tips on this.


This is the second time since friday that i charge my car to 90 percent. I did charge it back on friday.

If I had to speculate, this is the AC kicking into overdrive to keep your battery cool. The battery cooling loop is connected to the AC system with a heat exchanger and if it gets extra spicey the AC system will work to keep both the battery and cabin cool.

This is especially true after supercharging, when the battery gets extra toasty from all the watts being slammed into it.

I'm not actually certain what a Model 3's AC system can pull in terms of watts, but if I had to speculate it would be appropriate around 300-400W considering cabin size and motor thermal loads.

 

[AAKEE]

An Update on my 2021 march Model 3 P with 82.1 Pana Batt.
The rollercoaster continues.
View attachment 847533

I would perform a 100-0% drive to find the real battery capacity.
When done, You know your batt capacity and can disregard the BMS rollercoaster.

I recently did a 100-0% drive. I did because it was since long planned. My BMS had a overestimation for long time which changed to a underestimate. Both ways about 2kWh wrong. This was not the reason for the 100-0% test. But the result is interresting.
I had my own capacity calculation that needed a better check point than the BMS.

A 100-0 drive should be performed at not too high speed, as high speed causes heat loss from the battery that we csn not really estimate. Some 90-100 kph / 55-60 mph should be good as the car will use about enough power to load the battery cells with about 0.2C (the same as the standard for battery cell specs).

I have a M3P and did get 75.15kWh out of the battery, with 3.8kwh left. Parked at 0.27% SOC pöus the buffer.
So this means the capacity is about 78.95kWh.
(My drive was split, 240km in the morning then a 8hrs parking at work and then 278km drive. Best to do it in a single drive, to reduce losses during the parking.

Now I know the capacity. As a side note, it is spot on with my calculations.

I also know that the degradation will be slow from now on, so I couldnt care less about BMS being in different moods.

 

[Rocky_H]

I'm not actually certain what a Model 3's AC system can pull in terms of watts, but if I had to speculate it would be appropriate around 300-400W considering cabin size and motor thermal loads.

Oh, it's quite a bit more than that. 300-400 W can be used just from the car sitting on and the main computer being active, even if the AC isn't running at all. It's at least a couple of kW from heavy air conditioning.

 

[MP3Mike]

Oh, it's quite a bit more than that. 300-400 W can be used just from the car sitting on and the main computer being active, even if the AC isn't running at all. It's at least a couple of kW from heavy air conditioning.

I think it is closer to 6kW. I know it is more than 4kW, as when I am hooked to 4kW shore power and I precondition my vehicle the SoC goes down, as the AC can't provide all of the power that the HVAC is using.

 

[KenC]

Hello Everone,

I am somewhat frustrated with my tesla and I need support to understand what I am doing wrong. So I bought a 2020 tesla model 3 standard range plus rear-wheel drive with 5,295 miles.

I supercharged my car to 90%/212 miles. I drove10 miles back home and my charge went down to 81%/193 miles. Why is that? Why is my charge going down so quick?

I already took of cabin overheat protection, sentry mode. I put my car on chill mode. Idk what else to do.

My avr energy is almost 400.

Can someone please support me or give me tips on this.


This is the second time since friday that i charge my car to 90 percent. I did charge it back on friday.

It's 100F in your screen image. Overheat and Sentry are not going to affect your Consumption while you're driving, so those graphs won't reflect it. Your consumption seems high, but your speed, 70mph is not fast, I'd guess 235Wh/mile consumption without AC. And once you get on surface streets, your consumption should also be below 250Wh/mile.

I would test without running the AC, or run it as little as possible, and see your consumption.

Also, if you use ABRP, register for free, it will calibrate your car's consumption at 65mph. You should be between 200 and 250Wh/mile.

 

[AlanSubie4Life]

I think it is closer to 6kW. I know it is more than 4kW, as when I am hooked to 4kW shore power and I precondition my vehicle the SoC goes down, as the AC can't provide all of the power that the HVAC is using.

Yes, this is a good way to estimate, run it on LO open loop and check the charge rate on a high power charger and should be able to get a very good estimate that way.

I’ve not done it before. Surprised it is that high (I always figured a couple kW since it seems to have quite a bit less impact than heat which is something like 7kW). But maybe it is! Though it can run the heater as well when running the AC (which allegedly does not happen when you run it in LO). And that would be relevant to the OP, he was probably not running open loop.

Anyway I replied to the OP with the estimates and it doesn’t have to be quite that high to explain his results. But no further response. Shouting into the void.

 

[AlanSubie4Life]

Your consumption seems high, but your speed, 70mph is not fast,

Maybe I screwed it up but looked more like 20mph average speed.

 

[AlanSubie4Life]

Maybe I screwed it up but looked more like 20mph average speed.

Glad to see 9mi/26min is not ~20mph, and has received a disagree (actually 22mph). Am I missing something?

Does @phonetele226 know all? Please enlighten!

 

[AlanSubie4Life]

Yes, this is a good way to estimate, run it on LO open loop and check the charge rate on a high power charger and should be able to get a very good estimate that way.

I’ve not done it before. Surprised it is that high (I always figured a couple kW since it seems to have quite a bit less impact than heat which is something like 7kW). But maybe it is! Though it can run the heater as well when running the AC (which allegedly does not happen when you run it in LO). And that would be relevant to the OP, he was probably not running open loop.

Anyway I replied to the OP with the estimates and it doesn’t have to be quite that high to explain his results. But no further response. Shouting into the void.

Thanks for the info @MP3Mike.

I normally charge at 35.5mi/hr (it toggles between 35 and 36mi/hr). I believe these are actual displayed mi/hr (meaning they represent the actual rate at which displayed miles are expected to be added), so for my vehicle 234Wh/mi*35.5mi/hr = 8.307kW (which divided by the 0.88 efficiency I likely see is 9440W input (I see 40A @ 237V which is 9480W so that's pretty close)). These numbers are just to calibrate what the screen is telling us. (234Wh/mi is my actual energy content per displayed mile, while 245Wh/mi is my charging constant.)

Anyway I turned on the AC to LO, with windows open, and let it settle out (I think my fan speed was set quite high, though I didn't check). It went as low as 18mi/hr briefly, but once settled after about 1 minute was at 21mi/hr.

So that is 35.5mi/hr-21mi/hr = 14.5mi/hr. So that is 14.5mi/hr*234Wh/mi = 3.4kW. (So that is fan + AC.) So you're definitely right about the power. Of course these are all DC numbers. (I didn't try settings other than LO which may be higher if they also engage heat, which is what I have heard but not confirmed.)

I hadn't realized it could be quite that high (this is for a 2018 Model 3 Performance; heat pump vehicles may be somewhat different but should be similar because they have to accomplish the same function). But reviewing the analysis , that means that if the OP had the AC set to LO, open loop, with high fan speed, at 22mph average speed, that would add 3.4kW/22mph = 155Wh/mi to his average consumption. Of course steady state with windows closed, etc, it should be lower, but it might take a while to cool down a car that has been baking in the sun, and this was not a long trip.

So the baseline for that speed would be around 170Wh/mi-200Wh/mi (just a guess for that speed and vehicle), so that takes it to a minimum of 325Wh/mi, and as much as 355Wh/mi. So it wouldn't take a very large incline at all over 9 miles to get to 400Wh/mi. (45Wh/mi*9mi / ~1.6kWh/1000ft = ~250ft).

We'll never know the situation though; the poster has disappeared. But in general no mysteries here.

 

[3sr+buyer]

My avr energy is almost 400.

Was it a hot day when you had the AC blasting while sitting in traffic?

 

[AlanSubie4Life]

Was it a hot day when you had the AC blasting while sitting in traffic?

It was 100 degrees. See pic.

 

[ay221]

Should I charge my Tesla every day and night? | Optiwatt

What are the pros and cons of frequent charging? We took a look at all the factors, so you don’t have to, and here is what we found.

getoptiwatt.com

This article states that the less charging one does the better. bigger cycles vs daily small cycles.

 

[KenC]

Should I charge my Tesla every day and night? | Optiwatt

What are the pros and cons of frequent charging? We took a look at all the factors, so you don’t have to, and here is what we found.

getoptiwatt.com

This article states that the less charging one does the better. bigger cycles vs daily small cycles.

Interesting. I didn't see a source for the chart where he states a 20% Depth of Discharge results in more full charges than 10% DoD. Seems to go against other commonly cited research. Plus, it's non-intuitive, since in general, it's sequential, 20% is better than 40% which is better than 60%, which is better than 80%, which is better than 100%. Having 20% be better than 10%, is a bit of an outlier.

 

[STS-134]

I'm not actually certain what a Model 3's AC system can pull in terms of watts, but if I had to speculate it would be appropriate around 300-400W considering cabin size and motor thermal loads.

It's way more than that. I connected my car to my WC with the doors open and HVAC still running and I saw 8A@240V, about 2 kW. I can't directly monitor power draw in my Tesla but I can in my PHEV and the compressor in that car consumes about 1.5-2.5 kW, once the cabin reaches the set temperature. If the cabin is far above the set temperature (like after the vehicle has been parked), the compressor will consume up to 4 kW.

2 kW after the cabin reaches the set point seems like a fairly good estimate. It's probably even higher if the sun is beating down on that glass roof.

 

[AAKEE]

Should I charge my Tesla every day and night? | Optiwatt

What are the pros and cons of frequent charging? We took a look at all the factors, so you don’t have to, and here is what we found.

getoptiwatt.com

This article states that the less charging one does the better. bigger cycles vs daily small cycles.

Well, would you call a journalist or a real doctor when youvget ill?

They are wrong on many points in your link.

The marked part is….simply not true at all.

The marked part is also….not true.

The smaller the cycles the longer the battery will hold up. There is a lot more research than the only one batteryuniversity got their data, from where it looks like the opti-something people got their data.

This is what one needs to know:
- Charge often (daily)
- Do not charge to a higher SOC than needed.
-Charge shortly before the drive if possible, like the morning before the drive instead when arriving at home the day before.
-Leave the car with low SOC if it not is to be used for a period.

Thats it.


The basics, in short:
-The lower the SOC, the happier the battery is.
- The lower the temperature, the better.
-High SOC + high ambient temps for long time causes higher wear.
The smaller the cycles, the better.
The lower in SOC the cycles is placed the better.

 

[brkaus]

Well, would you call a journalist or a real doctor when youvget ill?

In 1990? Or 2022?

 

[AAKEE]

Interesting. I didn't see a source for the chart where he states a 20% Depth of Discharge results in more full charges than 10% DoD. Seems to go against other commonly cited research. Plus, it's non-intuitive, since in general, it's sequential, 20% is better than 40% which is better than 60%, which is better than 80%, which is better than 100%. Having 20% be better than 10%, is a bit of an outlier.

That article is filled by some Bs mixed with data similar to batteryuniversity. They refer to a very low number of research. Some of the research parts(data, graphs) they use is not correct. This is showed by a lot of other research reports.

Like I wrote earlier, would you go to a journalist or a real doctor when ill?

Most articles I have seen is done by people that did not learn enough about the subject and then try to write about it. It doesnt turn out well to learn people about something you do not know.
There is a few very bad statements in the article.

 

[Steve446]

An Update on my 2021 march Model 3 P with 82.1 Pana Batt.
The rollercoaster continues.
View attachment 847533

That's amazing. I am surprised by the magnitude of the peak-trough. My own car LR 2021 is doing something similar but not anything close to this wave height. I'll plot out my SMT data (close to 12 months age now) over the next couple of days. Question, have you done a BMS calibration or is this just, well, happening?

 

[conv90]

I would perform a 100-0% drive to find the real battery capacity.
When done, You know your batt capacity and can disregard the BMS rollercoaster.

I recently did a 100-0% drive. I did because it was since long planned. My BMS had a overestimation for long time which changed to a underestimate. Both ways about 2kWh wrong. This was not the reason for the 100-0% test. But the result is interresting.
I had my own capacity calculation that needed a better check point than the BMS.

A 100-0 drive should be performed at not too high speed, as high speed causes heat loss from the battery that we csn not really estimate. Some 90-100 kph / 55-60 mph should be good as the car will use about enough power to load the battery cells with about 0.2C (the same as the standard for battery cell specs).

I have a M3P and did get 75.15kWh out of the battery, with 3.8kwh left. Parked at 0.27% SOC pöus the buffer.
So this means the capacity is about 78.95kWh.
(My drive was split, 240km in the morning then a 8hrs parking at work and then 278km drive. Best to do it in a single drive, to reduce losses during the parking.

Now I know the capacity. As a side note, it is spot on with my calculations.

I also know that the degradation will be slow from now on, so I couldnt care less about BMS being in different moods.

Thanks @AAKEE .
Yes, you are right but i can't do it (yes I can, but if I have not a really need to do a long trip there is no a good reason to waste 500km or 75 kWh).
But even thinking to try it, I see a pair of uncertainties.
In my opinion it has to be performed whithout a stop. so in a real single run.
Because I have always this kind of behavoir:
When I charge it, I have this situation when I have the first stop (and first deep sleep):
The percentage raises.
Example: I charge to 60 or 65 (it's an example) , I stop for the first time at 50% . When (whtout Sentry... etc) I take it again, the % is 90% of the times MORE than 50%.
Say 52%. This is something that has to do with BMS .
There are 2 scenarios in my 2021 M3P 82.1 kWh batt on this:
1) The % went to 52% from 50% and the range in km rises accordingly (example left at 240 km at 50% and then at 249-250 at 52%)
This first scenario is usually when the NFP is in a UPperiod trend .
SO in this case what the BMS is doing?
This phenomenon i'ts sometimes so big that sometimes I made 50 km ("since last recharge" screen), AND the tripmeter says that I used only 5kWh (since last charge), like if the car can do 10km every kWh!
2) The % went to 52% and the range in km stay the same or more likely it increased less than expected (example left at 240 km at 50% and then at 245 at 52%). This reflects to NFP that goes down.
This 2nd scenario is usually when the NFP is in a period where it is going down trend.

This happens usually at the first and or sometimes 2nd sleep and when usually at around 50%.

When I use the car in the next days I progressively see the car loosing range accordingly with %. (so in a normal linear way).
BUT when at about 37-30% I have usually the opposite scenario when left parked for some hours:
The percentage is 35% , i take it back the car after rest at 33%.
So, when the NFP is in a UP-trend period, the range in km looses LESS than the percentage drop, and, when the NFP is in a down-trend period, the the range in km looses MORE than the percentage drop.

Another uncertainty is the fact that even using SMT resetting the trip (so to see the real consumption during the attempt to go from 100% to 0%) is that when you are at 0% or near 0% , SMT can say that you have still 3,8kWh left (just to use your example).
But who knows if this data is corrrect? (I think this data is still derived from BMS extimation).
It can be 4 kWh or 5 or 6 or 2 or 1 kWh. If the BMS is not calibrated.

The las time I discharged to -2,50% and usable remaining -1,80% and nominal remaining at only 1,60kWh, the cells where all well OVER 3.00.
If I remember 3.01x to 2,99x , letting me think that there are more left than only 1,60 kWh.

What I want to say is that even performing a 100 to 0% trip there is always some parameter strictly connected to the BMS calibration.

 

[AAKEE]

Thanks @AAKEE .

In my opinion it has to be performed whithout a stop. so in a real single run.

The best is a single run as the car could waist a bit energy parked.

Because I have always this kind of behavoir:
When I charge it, I have this situation when I have the first stop (and first deep sleep):
The percentage raises.

This is a result of the BMS being of track and underestimating the battery capacity (and this does not affect a 100-0% drive)

When driving the car (BMS) use the last SOC and reduce the SOC number with the consumed energy. If the car thinks the capacity is lower each used KWh will reduce the screen SOC little more than the real number.
For example, the BMS thinks 78kWh.
A drive from 100% with 39kwh used will result in 50% on screen SOC.
When the car goes to sleep the BMS will
measure the real
SOC by measuring the battery voltage.
The real SOC will be more than 50% as only 39 of 80kwh was used. The real SOC should be 51.25%, which the voltage measurement will show. After the sleep, the Soc is adjusted on the screen.

Energy can never occur in a battery during a pause/when parked, so the only thing that can happen is that the measured battery capacity show a lower number than the real
Capacity.

My BMS went in to a underestimation. I see the same behavoir with SOC increasing after a drive now. I did not have this
before.