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Discussion Starter #1
I mentioned on another thread that the Bolt's EFFICIENCY HISTORY screen is very badly wrong. Here is the issue:

Suppose you drive 5 miles at 247 mi/kwh. You used 0.02 kWh and the bar chart reads 247. Then you drive 5 miles at 3 mi/kwh. This uses 1.67 kWh and the bar chart reads 3. The average of the two bar readings is what GM is calling "Average energy consumption". That is 125 mi/kwh. Nice number. But gigantically wrong. The truth is about 6 mi/kwh. To quote someone on the other thread: "a bonehead error".

Details: 1.67 + 0.02 = 1.69 kWh; distance is 10 miles. The mileage rate is 10 mi / 1.69 kwh = 5.9 mi/kwh.

The error here is about 2000%. If someone is trying to maintain, say, a rate of 4, knowledge of this average is important. The bar chart is not helping. The red line is wrong. And the impression given by the bars is very misleading.

If you were driving very steadily, with bars between 3.9 and 4.1, the error would be less. I live in the mountains of Colorado, where steady use is never possible.

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I am trying to communicate this to GM, but so far the support staff I have contacted just say "energy use can vary", "it is just an approximation". I am trying to reach someone who understands arithmetic. I have prepared some notes on this -- they discuss this point, and also another interesting point about the difference between using miles per kWh (the USA way) and kwh/mile (the Euro and Canadian way, tho of course they use 100 km, not miles). I posted them at

<< stanwagon.com/public/BoltFuelConsumptionComputation.pdf >>

Digression: I actually favor the US Customary Units over the metric system, but that is not at all the point under discussion here. What the Europeans do in the particular realm of energy consumption ratios is far superior.

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There are other side issues, that are less important, but not negligible. If one goes down a long hill and gains kWh over a 5-mile stretch, the bar chart should show a negative number. But the programmer replaced any negative number (also any number larger than 252) by +252. The fact that negative energy exists is the whole point of a regeneration system. You would think that users could handle the concept. But clearly the designers did not think so, and chose to avoid negative numbers. I don't have a problem with that. I do have a problem with their saying that 125 is a reasonable approximation to 6.

If anyone knows someone who might know someone at GM who would care about this, do tell. It would seem like a very simple fix in the program to get it right. Just divide before taking the average, and then divide once more.

I can't upload my notes here directly because there is a very sharp limit of 20 KB (???) on file size.
 

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I live on a hill and found the bar chart useless. The information page which tells you how many miles and how many kWh used is useful and the trip display computes average mi/kWh. But honestly, i didn't find the bar chart worth analyzing.
 

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Discussion Starter #5
I have a photo of the screen. It is quite clear. The bar chart in my notes I made directly from the info in the photograph. It is clear from the posn. of the average that it is the average, but of the wrong thing. It is the average of the rates shown, and that is almost always above 30 here since we have big hills everywhere. As noted, the true average is almost always 4 to 6. I can't get the pic small enough to post. Ok: here is the pic. of the screen: http://stanwagon.com/public/BoltBarLowRes.jpg The red average line is at around 20. That is about the average of the 10 numbers shown. The truth is near 4. Note that 252 and the nine 4s averages to 29, which is where the red line is. The actual rate average -- the harmonic mean -- of the 10 numbers 252 and nine 4s is 4.4.

Jetson: That looks like great info. Many thanks.

TotalledJetta: If that red line was accurate, indicating whether one was above or below 4, then that would be useful I think. One can reset this at will, so can get the usage for a fixed stretch of road, perhaps comparing it over seasons etc. My mission is to get GM to make this easy fix.
 

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Do you think you may be looking at watt hours not KWH.. a normal EV will go 4 miles on 1 KWH or 250 watt hours or . 25 KWH?
for a mile.
 

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Discussion Starter #7
No. The vertical axis on the screen states clearly the whole thing is in mi/kWh. And the 252 bar that shows up occurs only on downhills. As noted, 252 is standing in for any very large number, and for all negative numbers. Most of the time the bar height is about 4 on this scale.
 

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Discussion Starter #8 (Edited)
And I guess I have a theory on how this error happened. The electronics were done in Korea I think. It is possible that they were told to switch from kWh/100 km to miles / kWh. Making that unit change was easily done. But then for the Euro/Korean system the straight average of the bars WOULD work. So that is what they did. Just speculation.

Wait: I just realized that somewhere there must be a place to switch from US Common -> Metric. Will this flip the bar chart so that it goes to the Euro/Can system of kwH/100 km? That would be great and would eliminate the problem, though of course one would have to work entirely in km and Celsius I suppose. I will check soonest.
 

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Discussion Starter #9
Yup, the problem disappears for Canadians! Switch to metric and the bar chart is perfect and the average is between 14 and 16 as expected and the whole chart is much easier to grasp. So the error was made by converting and then computing, as opposed to computing then converting. That is, if the khw/100 km chart, including the average line, was simply converted to miles it would be perfect. But they converted the bars and then took the (wrong) average. I find this all quite fascinating. But I also want GM to fix it.

I note that on the Options screen on the display behind the wheel there is a way to download the source code. I guess that is cool. If I could read the language I could download it, and fix it. But that wouldn't help what is installed on my car.
 

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stanwagon,

Thanks for continuing to pursue getting this corrected. It really drives me crazy. I'd prefer if they went to kWh/100 miles, but that is probably asking too much of a corporation.
 

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Yup, the problem disappears for Canadians! Switch to metric and the bar chart is perfect
You'd be surprised how many Canadians are employed in software development. And even AI development.

Now if you guys would just switch to metric like we did in 1971. All would be fine. :p

PS Can't always get the tail to wag the dog though. When I want to buy a litre of something at the auto store, most of the time I end up with a 946ml container. A US quart that is. Guess who made it & shipped it up here.
;)
 

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Discussion Starter #12
GJetson: You can get the screen you want my switching to metric. But you'd then have that metric measure throughout the system, which might not work well for you.

Cehjun: I know that you are in Toronto. I am Canadian-born and raised, but in USA since 1971. I wish there was a bit more scientific and sociological discussion of metric vs USA Customary, but there is not. Just because the US is essentially the only country in the world using their system, does not mean it is the inferior system. There are fascinating arguments on both sides, but debate usually deteriorates quickly I have found. There are some cool facts about Fahrenheit though. 0 degrees F. does have scientific basis as it is the coldest one can get water by adding salt to it (or something like that). And 100 was body temperature estimate at the time. I also just learned the factoid that both Fahrenheit's parents died the same day of mushroom poisoning. Mushroom picking is great sport here in the mountains, so I found that interesting.

If I ever write something professional about this, I will also have to bring in a logarithmic scale. That is the right way to present data when the scales widely differ, which happens with every downhill.

I see now how to get average speed for life of car. Cehjun: It is about 27 or 28 mph. Most of our driving is slow local (if hilly) driving. That probably goes a long way to explaining our current lifetime of 4.1 m/kwh, which you thought was high. I am not convinced that hills hurt very much. Slow definitely helps.
 

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GJetson: You can get the screen you want my switching to metric. But you'd then have that metric measure throughout the system, which might not work well for you.

Yeah, working on foreign cars, motorcycles, and bicycles most of my life, I can convert metric to US in my head, but learning US system as a child means I still do the conversion every time. Unfortunately, metric still has no meaning at the visceral level.
 

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Discussion Starter #14
As you can perhaps tell, I agree that the visceral level of "teaspoon", "cup", "foot","inch" is far superior to things like decaliter and deciliter.

I tried the web page that is listed in the Driver's Info Screen about OpenSource software. Could not make sense of what I saw there, but it led me to LG customer support, and from there to LG Software Developer, to whom I reported the metric bug.

I watch occasional Bolt review videos and always pick up little tidbits.

A. one can shut the engine off when in D. It works fine. Dealer said I always have to put in P. Not so.

B. going from L to D is tricker. Dealer did not explain it. But one simply taps the shifter backward, as if one were going to L ! Counterintuitive. If one is in L, that puts one in D. Useful.

C. There is an automatic washer for the rear camera. Great. I am not sure what activates it, but I suppose the rear windshield wiper would do so. Useful.
 

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one can shut the engine off when in D. It works fine. Dealer said I always have to put in P. Not so.
This is my standard mode. Just hit the power button and don't bother putting into park. If you watch carefully, you can catch the car putting into park for you. The P lights up for a split second. Others have stated that this prevents the car from using the parking brake properly. I've found the parking brake set on several occasions after just shutting off the car.
 

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C. There is an automatic washer for the rear camera. Great. I am not sure what activates it, but I suppose the rear windshield wiper would do so. Useful.
The camera washer is activated when you spray the rear window by pushing the wiper stalk forward.

If you watch carefully, you can catch the car putting into park for you. The P lights up for a split second.
If you're pressing on the brake pedal you can also feel it go down as the parking brake engages. Conversely, you can feel the pedal come up when you release the parking brake.
 

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Discussion Starter #17
But is there any downside to putting it in P from D? Does it activate the parking brake even tho user did not ask? Seems like it shouldn't. Out in 5 deg F weather this am. Heated steering wheel is nice!
 

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But is there any downside to putting it in P from D? Does it activate the parking brake even tho user did not ask? Seems like it shouldn't. Out in 5 deg F weather this am. Heated steering wheel is nice!
The car routinely puts the parking brake on by itself. I grew up near Chicago where you would never set your parking brake in the winter because it would be frozen on. Of course, in those days it was drum brakes in the rear with a mechanical linkage. Those would get water in the works and then freeze at night.
 

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Discussion Starter #19
Some progress. After getting no answer to my response via email I called again, and now there is a case number assigned to my metric->miles error complaint, and a Senior Adviser will call me within 2 days. Stay tuned.

Got home from a 150-mile cold trip today with 30 miles to spare. Watched all the green rects. turn orange a half mile from my house.
 

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Some progress. After getting no answer to my response via email I called again, and now there is a case number assigned to my metric->miles error complaint, and a Senior Adviser will call me within 2 days. Stay tuned.

Got home from a 150-mile cold trip today with 30 miles to spare. Watched all the green rects. turn orange a half mile from my house.
Great news! I hope they fix it.

So about 180 miles range on a full charge/60 kWh. You had 3+ bars when they turned orange?
 
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