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
 

cavell

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Wife’s Prius was simple. Dash says 50mpg. I use 10 gal to go 500miles. Seems right. I agree an ev is a way to use less $$ to go X miles. But, how much did you pay for it and how long will you keep it? Purchase price. Sale price. Money spent to charge while owned. How much did it cost to own it during life.
We had new Camry. Then got a Prius. Then got a civic. Wifey liked Prius best. But Prius was most expensive.
 

iub4pu

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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.
I would really like to know what is different about my Equinox EV efficiency and yours. I now have 1000 miles on mine (have had for a week :). I have not come close regardless of what type of driving I've done and how far I've driven to your 4 mi/kwh. Mine starts at 3.5 mi/kwh and starts going down within a mile or 2. If I drive 20 or more miles, mine always ends up at 2.7 mi/kwh. It is very frustrating. It is taking 30% of the range that I thought I would get. I've tried driving at different speeds, I don't take off fast at stops, I typically use cruise control on interstate driving setting at 74 mph if I'm traveling very far. I've even tried turning up AC to 72 degrees which is difficult in this 90 degree weather. I'm currently in Indiana which is flat and straight roads for the most part. What am I missing? Should I take it to the dealer to set if something is not right?
 

zippyzoe

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Efficiency is like an MPG for a gas car.

you get 15 mpg in ur gas car and you have a 10-mile tank == so you can travel 150 miles

If your car has a 3.5-efficiency rating and is 100% charged, you should be able to travel 350 miles.
The nice or not-so-nice thing is that your EV car will start to panic when you reach about 300 miles of range and start alerting you to charge.

Your ev car has a computer and its constantly computing data --

Factors That Can Affect Efficiency:​

  1. Driving Habits: Aggressive acceleration and high speeds reduce efficiency.
  2. Terrain: Uphill driving or rough terrain lowers efficiency, while flat or downhill routes improve it.
  3. Weather: Cold weather reduces efficiency due to battery heating needs.
  4. Load: Carrying heavy cargo or passengers impacts energy use.
  5. Tire Pressure: Underinflated tires increase rolling resistance, reducing efficiency.
 

stanwagon

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I have had the car for a while now and have figured out all gauges. There are some issues because I live atop an 800-foot hill. After a charge, if I should reset the trip odometer, it will not recognize the gain in kWh from my initial descent. GM programming does not allow negative numbers. Bottom line, I am getting the numbers I need and I can report 4.2 mi/kWh since purchase in June. That is excellent and way above the rating of 3.2. That would be a 357 mile range, except of course it will decrease in the upcoming colder months. Maybe I can get 4.0 0r 3.9 for the year, which will he impressive, given that 3.9 was the rating for the much smaller Bolt. The gauge tied to the current trip always starts at 3.2. If one goes only downhill that 3.2 will slowly rise, but the true answer since 0 kWh have been used should be negative, or infinite. But I can deal with it all -- because another window shows the exact kWh used and miles driven -- and am getting the numbers I need. I keep Trip 2 with no reset, so that is my lifetime rate.
 

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