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Guess O Meter Improvement

4898 Views 62 Replies 19 Participants Last post by Crwddyz, Dec 8, 2021

Rthardison

Discussion Starter · Dec 2, 2021

I suggest the GOM be converted to % battery charge instead of estimated miles left. We would still have maximum and minimum mile estimates. That gets us away from always saying the GOM is wrong. This would also keep me from trying to count bars with my eyes off the road. Haha
At least make it an option to see % charge instead of miles. In my opinion % charge is more meaningful than a mileage estimate which is always wrong due to so many variables. Hopefully GM will read this. Doubtful I know.

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Openair

· #41 · Dec 3, 2021

Herbie Bolt said:
I am unsure about your statement about the trend vector turning yellow or green, what am I missing here @AZBILL ?

With the enhanced dic and it's min, mean and max range estimates you will see a green trend bar grow from the mean towards the max estimate when you're getting better efficiency then previously or a yellow trend bar grow towards the min estimate when getting worse efficiency than the mean range estimate. This trend bar depicts moment to moment changes in efficiency.

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Herbie Bolt

· #42 · Dec 3, 2021

Openair said:
With the enhanced dic and it's min, mean and max range estimates you will see a green trend bar grow from the mean towards the max estimate when you're getting better efficiency then previously or a yellow trend bar grow towards the min estimate when getting worse efficiency than the mean range estimate. This trend bar depicts moment to moment changes in efficiency.

Thank you @Openair i haven’t noticed that, when you say enhanced DIC is that part of the software update or on newer models? Mine is a 2018.

Openair

· #43 · Dec 3, 2021

Herbie Bolt said:
Thank you @Openair i haven’t noticed that, when you say enhanced DIC is that part of the software update or on newer models? Mine is a 2018.

Mine is also a 2018. No update required. The dic has 3 modes that can be switched between from a menu on left. Classic, modern and enhanced. Changes the instantaneous consumption display style as well.

enslay

· #44 · Dec 3, 2021 (Edited)

Sean Nelson said:
I hope you understand that the efficiency number is averaged only over the distance since you last reset it and is strictly a measure of energy used vs miles driven.

C'mon man... how many times do I have to say this... I hope you understand how to compute efficiency manually.

enslay said:
Why doesn't this DIC thing really matter? Because the Infotainment system will report miles driven and kwh hours consumed. You can simply divide the two quantities to get miles/kwh... no issue right? And these values reset when you recharge.

I will further add that the energy reported in the Infotainment includes factors like HVAC. I'm sure you've seen the "Climate" breakdown of energy consumption. The manual efficiency calculation will capture those factors implicitly.

Sean Nelson said:
Meanwhile the range estimate is a much more speculative algorithm that attempts to predict the future by drawing on many factors including temperature, HVAC consumption, efficiency during previous driving cycles, etc. - and it's heavily biased by the very recent past.

I showed you the recent past (50 miles history). Explain the discrepancy... is it heavily biased by my consistent 4 miles/kwh efficiency in the last 50 miles (achievable only via regen!), or is it heavily biased by my 75 mph speed? I think this is obvious.

"Ironclad agreement" is an understatement. We're talking about a 50 mile range discrepancy. We're talking about a difference of 4 miles/kwh (manual calculation, Infotainment) vs 2.86 miles/kwh (Chevrolet).

Sean Nelson said:
But yes, the range estimate does take regen into account.

If it actually takes regen into account, explain the discrepancy in my numbers! Explain Chevrolet's numbers.

On the other hand, it could behave the same for you if it didn't take regen into account... because it could do something like this:

enslay said:
Although averaging max(0, energyConsumed) where energyConsumed < 0 is regen would have a similar effect as he posted.

Yeah, I don't know. All I know is Chevrolet's number is 2.86 miles/kwh and it aligns well with the GOM prediction. And I know that there's no way I could have 4 miles/kwh driving 75 mph for 20-30 minutes. Impossible without regen.

Sean Nelson said:
So of course you won't see ironclad agreement between past efficiency and predicted range - that's only to be expected since they're based on different data and are serving different purposes.

It's measuring the same data, and possibly using the same sensors and possibly augmenting it with other extra measurements (e.g. outside temperature). GOM is doing something DIFFERENT with that data.

I hope I've successfully empirically demonstrated that the GOM is NOT some simplistic rolling fuel calculation like found in DIC and Infotainment. It's a more sophisticated, in your words, speculative algorithm.

EDIT: Maybe the GOM is a Kalman filter

en.wikipedia.org

Kalman filter - Wikipedia

en.wikipedia.org

en.wikipedia.org

In a very strange way, it would be a kind of rolling average calculation. Just not with scalar values and weights.

I'll have to think if such a hypothetical Kalman filter can have consistent behavior between both of our observations.

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Herbie Bolt

· #45 · Dec 3, 2021

Openair said:
Mine is also a 2018. No update required. The dic has 3 modes that can be switched between from a menu on left. Classic, modern and enhanced. Changes the instantaneous consumption display style as well.

Thanks again, I’ll go for a drive today look for that trend bar. To verify when you say menu on left are you referring to the menu options on the steering wheel?

enslay

· #46 · Dec 3, 2021 (Edited)

Herbie Bolt said:
Thanks again, I’ll go for a drive today look for that trend bar. To verify when you say menu on left are you referring to the menu options on the steering wheel?

Don't worry. It's a subtle feature that's hard to notice. I didn't notice it for a while either.

Have a look at this picture:

http://imgur.com/OzFohTW

On the very left of the 151, there's a gray arc. See it? The arc extends from the 178 max range down toward the 123 min range.

When trending above average, a green line will fill the gray arc starting at 151 and rising along the arc toward the top of the image (toward 178).
When trending below average, a yellow line will fill the gray arc starting at 151 and falling along the arc toward the bottom of the image (toward 123).

EDIT: I will add that the length of the line varies by how much you trend above/below. So if you're trending "a lot", the line could very well touch the 178 or 123 marks. If you're trending "a little", might be a small line far from touching 178 or 123 marks.

You can also see it from @Sean Nelson 's post (his is trending upward "a lot").

Sean Nelson said:
View attachment 39068

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Openair

· #47 · Dec 3, 2021

Herbie Bolt said:
Thanks again, I’ll go for a drive today look for that trend bar. To verify when you say menu on left are you referring to the menu options on the steering wheel?

Yes, the steering wheel controls.

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AZBILL

· #48 · Dec 3, 2021

Herbie Bolt said:
I am unsure about your statement about the trend vector turning yellow or green, what am I missing here @AZBILL ?

When the range is trending down, the trend vector on the left side of the battery gauge turns yellow and elongates down toward the minimum range value. See this photo, the trend vector is yellow and slightly trending down, just below the 164 mile indication:

Gauge Font Cloud Measuring instrument Screenshot

If the trend is going up, that bar on the left of the battery gauge will turn green and be above the 164 mile on the display, not below it. The faster the range is trending in either direction, the longer that bar will become.

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Herbie Bolt

· #49 · Dec 3, 2021

enslay said:
Don't worry. It's a subtle feature that's hard to notice. I didn't notice it for a while either.

Have a look at this picture:

http://imgur.com/OzFohTW

On the very left of the 151, there's a gray arc. See it? The arc extends from the 178 max range down toward the 123 min range.

When trending above average, a green line will fill the gray arc starting at 151 and rising along the arc toward the top of the image (toward 178).
When trending below average, a yellow line will fill the gray arc starting at 151 and falling along the arc toward the bottom of the image (toward 123).

EDIT: I will add that the length of the line varies by how much you trend above/below. So if you're trending "a lot", the line could very well touch the 178 or 123 marks. If you're trending "a little", might be a small line far from touching 178 or 123 marks.

You can also see it from @Sean Nelson 's post (his is trending upward "a lot").

I honestly never noticed that, thank you @enslay @AZBILL and @Openair

Sean Nelson

· #50 · Dec 3, 2021

Herbie Bolt said:
Thank you @Openair i haven’t noticed that, when you say enhanced DIC is that part of the software update or on newer models? Mine is a 2018.

It's called "enhanced" because there are several display options for the DIC and the one that shows the trend indicator is called the "enhanced" option. It has nothing to do with software versions.

From the owner's manual:

Font Number Document Screenshot Event

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Herbie Bolt

· #51 · Dec 3, 2021

Sean Nelson said:
It's called "enhanced" because there are several display options for the DIC and the one that shows the trend indicator is called the "enhanced" option. It has nothing to do with software versions.

From the owner's manual:
View attachment 39076

Thanks @Sean Nelson

Sean Nelson

· #52 · Dec 3, 2021

enslay said:
If it actually takes regen into account, explain the discrepancy in my numbers! Explain Chevrolet's numbers.

My purpose in enjoining this discussion was to show that regen affects the GOM, and I've done that. I don't know what your driving conditions have been, but I will tell you that normal "around the town" regen won't show up on the GOM because it doesn't last long enough. The GOM algorithm tries to strike a balance between long-term trends over days and briefer trends over several minutes. But it mostly ignores short term anomalies. You don't want the range estimate to drop just because you're using a lot of power for 15-30 seconds in order to merge onto a freeway or to rise just because you're decelerating back onto city streets using regen. You need to have a sustained change in power consumption or regeneration over several minutes in order for it to show up as a change in estimated range.

I'm not going to get into debates about past efficiency vs. estimated range because they are apples and oranges and I see no point in it. If you feel your numbers are cause for concern then I guess your best course of action is to talk to your dealer about it. Good luck with that.

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enslay

· #53 · Dec 3, 2021 (Edited)

Sean Nelson said:
I'm not going to get into debates about past efficiency vs. estimated range because they are apples and oranges and I see no point in it.

No, it's because you can't explain it. You "see no point" because you don't know. There's the numbers from myself and WIND-WORKS and your observations pooled.

EDIT: Just so you know, there's nothing wrong with not knowing.

Sean Nelson said:
If you feel your numbers are cause for concern then I guess your best course of action is to talk to your dealer about it. Good luck with that.

If you participated in the thread, the consensus from other posters was that the GOM is some kind of "fuel economy type of calculation" (EDIT: As in some kind of simple rolling average). I have completely thoroughly debunked that misconception... again (this is not the first time).

I never indicated any cause of concern for my numbers anywhere in this thread.

spear

· #54 · Dec 3, 2021

My 2020 Bolt does have a similar discrepancy that @enslay sees between DIC average mi/kWh and GOM range: 4.1 mi/kWh but only ~170 miles at 80% (actual 77%).

I'd been attributing it to the GOM not knowing the correct battery capacity. I think Sean Graham has mentioned somewhere that you need to discharge to below 40% for at least 4 times before it will figure out the capacity and I have never discharged that low. (Also, I've only charged up to 100% once.)

A few months ago, the GOM actually started displaying more reasonable numbers: ~210 miles at 80%. This was soon after I had discharged to the lowest I'd ever gone (~45%) so I thought maybe it had figured out the correct capacity. However, it reverted to the low GOM numbers after a couple of charging sessions so I don't really understand what's going on.

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cwerdna

· #55 · Dec 4, 2021

cwerdna said:
That used to work until it stopped working for months. I haven't bothered trying again. The app w/CarPlay for awhile was a dumpster fire where it would do nothing on the CarPlay screen other than show a spinning cog, possibly with a stale number. The rest of the apps I use with CarPlay work ok or fine (e.g. Spotify, Apple Maps, Waze, Google Maps, Pandora).

I just use their app on my iPhone 8 by itself but sometimes it's broken and shows a stale value. When that happens, I have to switch to using the my Android phone w/the My Chevrolet app.

So, I tried it the other day while driving and I was #$%#$% signed out of the app. After signing back in (luckily, my password was saved on my iPhone 8), the functionality to show the % SoC on the CarPlay display was broke ass. It kept putting up an error w/a blue and red icon (IIRC) saying that the data wasn't available or something like that.

I haven't read this thread carefully but as someone discovered at The math behind min/max calculations, and the energy..., the min and max scores are usually the middle value * 0.82 and 1.18, respectively. Sometimes, the min value isn't the * 0.82, for some reason.

Voldar

· #56 · Dec 4, 2021 (Edited)

Rthardison said:
I suggest the GOM be converted to % battery charge instead of estimated miles left. We would still have maximum and minimum mile estimates. That gets us away from always saying the GOM is wrong. This would also keep me from trying to count bars with my eyes off the road. Haha
At least make it an option to see % charge instead of miles. In my opinion % charge is more meaningful than a mileage estimate which is always wrong due to so many variables. Hopefully GM will read this. Doubtful I know.

I already posted into another thread, but I’ll post here too. You have the GOM as you want it, just you aren’t aware of it. It is called MyChevrolet app and it works just fine. Here is an exemple of what you can get :

Communication Device Gadget Portable communications device Mobile device Display device

As everyone knows, the Bolt EV does it’s rage estimation based on the last run, not based on the history of the passed runs. So, if it says I will arrive home with 7% SOC, it is gonna be spot on, as long as I drive the same (same kW/100 km) as until then. The image was taken while I was charging on a DCFC and soon after I ended the session then went home. Spot on !

P.S. It needs though an OnStar subscription. But hey, I pay a lot more per month for stupid things. At least from this I can get some benefits !

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enslay

· #57 · Dec 4, 2021

spear said:
My 2020 Bolt does have a similar discrepancy that @enslay sees between DIC average mi/kWh and GOM range: 4.1 mi/kWh but only ~170 miles at 80% (actual 77%).

I'd been attributing it to the GOM not knowing the correct battery capacity. I think Sean Graham has mentioned somewhere that you need to discharge to below 40% for at least 4 times before it will figure out the capacity and I have never discharged that low. (Also, I've only charged up to 100% once.)

A few months ago, the GOM actually started displaying more reasonable numbers: ~210 miles at 80%. This was soon after I had discharged to the lowest I'd ever gone (~45%) so I thought maybe it had figured out the correct capacity. However, it reverted to the low GOM numbers after a couple of charging sessions so I don't really understand what's going on.

Maybe. I'll have to try discharging it below 40% once I get the new software (who knows when!). I charge it everyday in accordance to the recall... which vaguely recommends "charging more frequently" or something like that.

I attribute the GOM's estimate to daily driving at 75 mph. And the Chevrolet monthly diagnostics e-mail provides an efficiency value that matches the GOM's predictions. The DIC or even manual efficiency calculation shows around 4 mi/kwh. And that's surely due to regen and going downhill.... There's just no way I could manage that at daily 20-30 minutes continuous 75 mph driving.

Voldar

· #58 · Dec 4, 2021 (Edited)

enslay said:
The GOM does not use your Infotainment measurements or DIC.

I am not sure what part of the sentence you can’t understant: the GOM value is based on the value "of the efficiency" before the last reset. This value is based on the 3 T (temps, terrain and technique) including regeneration and everything you think it might not be taken in consideration.

Showing the last 50 km efficiency numbers and intentionally hiding the real m/kWh on board (by showing the tire pressure info screen) registered since the moment you reset last time the m/kWh is useless and you don't prove anything but the fact that for the last 50 km you drove very efficient, maybe 50-55 mph. Nowhere in the screens you show is 75 mph indicated.

I have my Bolt EV for long enough to know very well that it’s GOM is one of the best on the market. It never failed to "predict" very accurate and it’s simple for me to calculate what I need to do to go where I want:
For exemple, if I need to go 300 km and I have a previous consumption of 23 kWh/100 km… this tells me I will need to stop charging for 15 minutes at around 250 km mark if I keep the same 23 kWh/100 km or that I should slow down the speed to get about 19 kWh/100 km and not charge at all before destination. That’s why I love the MyChevrolet app because it tells me exactly the SOC of my battery.

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enslay

· #59 · Dec 4, 2021 (Edited)

Voldar said:
I am not sure what part of the sentence you can’t understant: the GOM value is based on the value "of the efficiency" before the last reset. This value is based on the 3 T (temps, terrain and technique) including regeneration and everything you think it might not be taken in consideration.

No it's clearly not.

You wrote that I am very efficient at driving and you're somehow telling me that I drive at "maybe 50-55 mph" and yet the GOM spits out range values of 151 (for example)... it's usually more like ~160. It's not like a one-off thing. This is every day for months! OK? Do I need to start a blog and upload pictures everyday or something?

Do you know why the GOM likely spits out range values like 151? Because I drive 75 mph for about 20-30 minutes (one way) every weekday for the past 6 months. Some of its downhill, I get some regen when I get off the highway. But ultimately, most of my commute is at 75 mph.

Voldar said:
Showing the last 50 km efficiency numbers and intentionally hiding the real m/kWh on board (by showing the tire pressure info screen) registered since the moment you reset last time the m/kWh is useless and you don't prove anything but the fact that for the last 50 km you drove very efficient, maybe 50-55 mph. Nowhere in the screens you show is 75 mph indicated.

What, do you want me post a new picture of essentially the same numbers, every single day for months on end? No, it's 75 mph on about a 10 mile stretch of interstate highway. My gosh, why would I lie about my commute?

Here's what I generally look at in the morning when I arrive at work and later in the evening when I arrive home. It's very hard to make a mistake from this... and I roughly see this (more-or-less) every single day! Here's an example of yesterday when I arrived at work:

http://imgur.com/eFY2JDx

And this resets on recharging. It's hard to be mistaken from manual calculation from these numbers (just divide them). Criticize the efficiency screen or DIC all you want... this is consistently about what I see in the morning and evening and there is no possibility of factors like the DIC not being reset or something like that since this just simply reports miles driven and kwh consumed (since last full charge and I charge every night).

Voldar said:
I have my Bolt EV for long enough to know very well that it’s GOM is one of the best on the market. It never failed to "predict" very accurate and it’s simple for me to calculate what I need to do to go where I want:
For exemple, if I need to go 300 km and I have a previous consumption of 23 kWh/100 km… this tells me I will need to stop charging for 15 minutes at around 250 km mark if I keep the same 23 kWh/100 km or that I should slow down the speed to get about 19 kWh/100 km and not charge at all before destination. That’s why I love the MyChevrolet app because it tells me exactly the SOC of my battery.

"It works for me, so it must be perfect for everyone else"

I am relatively sure it's working correctly for me because I drive daily at 75 mph for prolonged periods of time (i.e. inefficient). That's why I get figures like 151 miles for range estimates at 80% SOC - and inspite of regen scraping back some on some of that inefficiency. And the myChevrolet efficiency numbers seem to convey the same thing (and surprisingly on the dot with GOM!)... for example last month, I get 2.86 miles/kwh (35 kWh/100 miles). But you see that screenshot above? I still see numbers like that everyday. That's all regen and some downhill driving.

EDIT: For those sticklers out there... I went cross checked with Google Maps. While the entire commute is 20-30 minutes, about 11.7 miles is highway driving of the 16 or so mile commute. The time spent at 75 is about 10 minutes.

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Voldar

· #60 · Dec 4, 2021 (Edited)

enslay said:
EDIT: For those sticklers out there... I went cross checked with Google Maps. While the entire commute is 20-30 minutes, about 11.7 miles is highway driving of the 16 or so mile commute. The time spent at 75 is about 10 minutes.

So for the sticklers, you do in fact 9 mins at 75 mph (get out of the way the 38 seconds for acceleration/deceleration) and the other 10-20 mins you do it in stop and go traffic. The Bolt EV is doing about 3.3-3.4 m/kWh at 75 mph and in the stop and go the number can very well rise up to what you see, around 3.7 m/kWh (16.7/4.5 shown in the above picture).
Now, the problem you have is that you see 151 miles on your GOM at 80% of SOC right ? With 178 miles best and 123 miles at worst. I don’t see a problem at all !
Based on your pictures above, you would see 188 miles at 100% in average and 222 miles at best at same 100% SOC on your GOM.
Your average consumption is 3.7 m/kWh, then at 100% SOC with 57 kWh available battery (could be lower) it means : 210 miles. I really don’t see any problem having a 10% difference between the values you see and the ones calculated. All you do is nitpicking just to prove something you fail to prove.

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