Understanding the economy numbers

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stanwagon

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I have had my 2024 Equinox EV for only a few days. I am selling my 2017 Bolt, which was a fine car. The Bolt showed energy used (it reset whenever one charged to full, or hilltop reserve). The Equinox is more flexible and has two trip odometers as will as a TRIP data set. So I can use Trip2 to lifetime, and I can use Trip1 to gain info for various trips. But some things are not making sense. Today I found the little car diagram with some plus signs. Hitting them, I saw an "ENERGY USED" display that showed how much I used on current trip. Great, because when I divide miles by that I get mi/kWh for current trip. But the TRIP window showed a completely different number. Details: The car image showed 2.5 kWh. The trip window showed 8.6 miles and average efficiency of 2.9 mi/kWh. But 8.6/2.5=3.44. This was my first drive, and over generally flat terrain, so the 3.44 seems perfectly reasonable. I could also make an attempt to use the %age of battery (based on 85 kWh battery), but that is not a good way to study this. So my main question is: Can that 2.5 EnergyUsed number be correct? It just seems wrong.

And it took me a while to figure out that the estimated economy is 3.2. If I use the sticker number of 28 kWh per 100 miles, that givers 2.85 mi/kWh. Review my Bolt sticker, it said 28 kWh per 100 Miles, which is 3.57 mi /kWh. But the actual EPA rating on the car was 4 mi/kWh. So these EPA numbers are totally confusing. I did look into all this very closely 6 years ago, and I even have an email somewhere from someone at the EPA. My actual Bolt numbers were will over 4, and in warm weather I am routinely getting 5.5 mi/kWh (I have the new batteries and I live near 10000 feet so air resistance is very low).

Thanks in advance for any comments. I learned an awful lot from the Bolt users group over the years.

Stanley Wagon (I can't resist giving my full name, b/c there is actually a car called a Stanley Wagon from about 1910; so I am a car! Stan)

PS: There are many other questions I am pondering. E.g., when leaving my driveway I drop 800 feet. The Bolt would gain 0.7 kWh on the descent. I wonder if the heavier Equinox will gain more.

PPS: Driving from the Denver dealer to the Eisenhower Tunnel before descent on the W side to my house, the fuel economy was somewhat over 2 mi/kWh, which is pretty impressive as this involves climbing over 6000 feet (at freeway speeds).

PPPS: There is also a chart that shows average kWh/mile in the last mile. I can make no sense of it. The descent from the tunnel is about 7 miles. The average is a negative number, but GM refuses to use negative numbers (I had lengthy discussion with Bolt engineers on this point). So it says something like 3.5 for the entire descent. Maybe it is regenerating at that rate? But it does not seem to make sense.


Screen Shot 2024-06-15 at 2.40.46 PM.png Screen Shot 2024-06-15 at 2.40.31 PM.png
 

stanwagon

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0 views I think. Have I somehow put this in the wrong place? Anyway I figured out the weird behavior. The "Energy Usage" -- 2.5 kWh in my pic -- does not update in real time. If one leaves the screen and returns, then it updates. This must be a bug.
 

stanwagon

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This is first reply to my comment in a couple weeks! But I am finally figuring it out. Being able to reset trip odometers is important. The good news: After 300 miles (some, but not a lot, of freeway driving) I am averaging 4.0 mi/kWh. This is pretty remarkable. The 2017 Bolt was rated at 3.9 (but it got a lot more: average about 4.3 for me). But given the extra size of the E'nox, seeing 4 is very good.
 

Hey Vern!

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Hopefully some new ev drivers join the forum. Stan you are probably further ahead that most of us, because you had a Bolt. I have zero ev experience.
 

stanwagon

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OK. Do I take it you have an Equinox EV? If no, none of this is relevant. If yes, you might be interested in a couple things. When I start driving I immediately go down 800 feet. There is regen of course. One of the charts says that I regenerated 2.7 miles and that appears to be based on the default 3.2 mi/kWh. But then the listed rate is this same 3.2, or that bopped up a bit. But this make 0 sense because for the trip so far the rate is negative. GM refused to allow owners to think about negative numbers. Well, I have become expert in all this and wrote a generally accessible paper on the subject. If you care you can get it at stanwagon.com/public/MHArticleProofs.pdf It is definitely an interesting area of study, both for mathematicians like me, and automotive designers. Tesla takes a completely different approach. In short, there are a lot of problems with the display, but with some care one can deduce what one wants. All this can be somewhat important since if, say, I have gone down to Denver I need to make sure I have enough juice to climb back to the 11000 ft tunnel to get home, and for that the mileage estimates will be completely useless as it is a climb of over 7000 feet.
 

Hey Vern!

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OK. Do I take it you have an Equinox EV? If no, none of this is relevant. If yes, you might be interested in a couple things. When I start driving I immediately go down 800 feet. There is regen of course. One of the charts says that I regenerated 2.7 miles and that appears to be based on the default 3.2 mi/kWh. But then the listed rate is this same 3.2, or that bopped up a bit. But this make 0 sense because for the trip so far the rate is negative. GM refused to allow owners to think about negative numbers. Well, I have become expert in all this and wrote a generally accessible paper on the subject. If you care you can get it at stanwagon.com/public/MHArticleProofs.pdf It is definitely an interesting area of study, both for mathematicians like me, and automotive designers. Tesla takes a completely different approach. In short, there are a lot of problems with the display, but with some care one can deduce what one wants. All this can be somewhat important since if, say, I have gone down to Denver I need to make sure I have enough juice to climb back to the 11000 ft tunnel to get home, and for that the mileage estimates will be completely useless as it is a climb of over 7000 feet.
I do not have an ev. 2018 gas 2.0. I do find the ev interesting, but it's not in my future
 

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