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Discussion Starter · #1 ·
On this thread I asked how people got so much higher m/kWh than I did. The discussion starter said he got 4.4 to 4.6. I almost never see more than 3.9 so I was wondering if something was wrong with my Bolt.

Several people answered that they were getting numbers like 5 and 5.2.

So this morning I ran an experiment. (I'm a research engineer I do things like that.) It was a lovely late spring morning and I figured I could do without the A/C, so I turned the car on and turned off the A/C, I then plugged the charger back in and as I hoped, it thought it was a new full charge and reset the "since last charge" numbers. I reset the trip meter and the efficiency report screen. The GOM read 212 (I have the charge limit set to 90%).

I then drove as conservatively as I could stand to work (50 miles). I did not go over 60 mph, I did not go above the speed limit, I did not accelerate hard, I did not use the breaks (just the regen), I drove in L the entire time.

The first entry on the efficiency graph was less than 3. This was not unexpected because there is a hill called "the divide" that I have to climb and for about a mile the car has to expend about 60-65 kW to maintain 60 mph. After that things improved and I was at times getting graph entries of 5.5 to 6. The trip meter efficiency number went up as I drove I saw as much as 5.4 and finished at work with 5.3.

At one point the GOM started counting up. I finished after 50.2 miles with 203 on the GOM after starting with 212.

So, there is nothing wrong with the car. The problem is obviously the driver. I had to really concentrate to maintain the rules I set for the test and I felt in danger of being run over by a giant pickup truck by only doing the speed limit (it's Texas after all).

If I drove like that all of the time, I could apparently get more than 90 additional miles out of a charge. And die of boredom. I normally drive a car for all it's worth, my daily driver has always been a sporty car and I drive the Bolt the same way. When I pull out on a road I generally accelerate as hard as is safe until I am at the speed of traffic. I believe that no one should have to slow down because you entered the traffic stream (either don't pull out or accelerate hard enough you don't interfere with other drivers). I do drive 5 to 10 mph over the speed limit if traffic permits. (I actually don't think they give speeding tickets in Texas anymore, the last several times I was stopped, I just got a warning.)

So, now I know the Bolt is fine. But, I think I will just be happy with my 3.9 m/kWh and drive like me.

(Nothing here is meant to be derogatory about other drivers, those who get high mileage are probably safer, happier, more content drivers that I am.)
 

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3.9 is a respectable number for freeway driving, particularly if you're usually going above 60 mph. If nothing else, this serves to point out the considerable differences in driving situations and styles that explain why people get such different results and why complaints about "my range is too low!" are looked at by longtimers on the forum with a jaundiced eye.
 

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Try the same experiment with limiting top speed, but accelerate as hard as you want. I bet you won't find much of a penalty.

Slow acceleration is not necessary for efficiency for either ICE or EVs. Way more important is limiting cruising speed, and not having to use the brakes.

Since you're an engineer, you might appreciate this graph. It took me like half an hour of staring to finally understand it, but basically the most fuel efficient operation in this engine is to give 3/4 throttle and target 2500 RPM. Every ICE is a little different, but this is roughly true for all of them.



Even more forgiving for an EV motor:

This map ranges from 82%-94% efficiency. Even if you hammer it, efficiency is high. Even if efficiency isn't high, you spend only a fraction of your time accelerating, and the majority of time maintaining speed / overcoming drag.
 

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Well at least now you know if you are low charge How to squeeze out the extra miles to get you to a charger. That in itself should make you a bit more comfortable when taking longer trips.

the other day I was stuck in traffic for about 15 miles of my 32 mile commute, I noticed that I used less energy that day.

I average normally 3.9 miles/ kwh
 

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I have had my bolt for 2.5 months. Its the quickest car I have ever owned, believe it or not. I almost never get much above 4.0. That rush of acceleration is intoxicating. The heck with range. I have found that range depends alot on how heavy your foot is and how much , as my wife calls it, zipping around, not so much how fast you go over a longer distance for around town driving. For me to get those 5.0+ numbers I would have to drive like those people I routinely curse and waive my arms at when I am in traffic. You know, those people you wonder if they know the Right pedal is the one they should be stepping on when you are behind them?
Having said all that, everyone has the right to drive how they feel comfortable. Its truly not a race. I would just prefer they feel comfortable in the right lane... :)
 

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My commute (now only once every few months) is 130 miles round trip. My best round trip efficiency was 6.5 mi/kWh, it averages 5.2 including cold CO winter driving. I know, I tracked it for 3 years!

I literally live at the top of a hill, at 7500 feet elevation. My office is at about 5000 ft. I have the choice of two routes, one is Interstate with speeds between 55-75 for all but 3-4 of the total miles. The other is a mix of back highway with 45MPH average speeds, expressways, and 10 miles of Interstate at 55MPH. The distance is nearly identical, the time is typically no more than 10-15 minutes longer on the alternate route. But the interstate runs through the heart of Denver and gets congested often and construction seems to be a permanent feature. The alternate route is a winding two lane highway that runs through pastures, forests, and has scenic views of the Rocky Mountains. It is a relaxing way to unwind after a long day at the office, and the morning sunrise views are incredible. I rarely see more than 10-20 cars (both directions) on the back highway in the morning.

The interstate has delays, sometimes as much as a couple of hours. The alternate route never has delays other than the Interstate section. So, over time, the average driving time is probably equal or in favor of the slower route. So, I typically avoid the interstate route.

Going to the office, I have seen efficiency as high as 10 mi/kWh.

So, it really depends on route selection, driving technique, climate conditions, and tolerance for temperatures (ie avoiding HVAC use).

Your approach was wise, try different routes and techniques. If the time is more important to you and faster routes with lower efficiency make sense, by all means go that route. But if you have the luxury of slowing things down, the roses smell nice this time of year!

I always use Hilltop Reserve, so never charge more than 88%. Following some of these highly efficient trips, I have seen the GOM report middle range figures as high as 275, and regularly (in the summer) see over 300 miles of range after the first downhill leg of my commute.
 

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So, now I know the Bolt is fine. But, I think I will just be happy with my 3.9 m/kWh and drive like me.
This this this, so much ^^this^^

The Bolt is a fantastic vehicle and people should drive it the way they want. They should use the HVAC the way they want, charge the way they want, treat the car they paid for as their own. BUT all of those things come with their own tradeoffs. Too many people think that seeing anything except for 259 on the GoM means something is wrong with the car. I've seen people infuriated (even going as far as accusing GM of "bait and switch" or misrepresenting the range) that they can't drive 80 on the highway with the heat blasting and have 259 miles of range. One person even said that GM needed to include an option to always make the GoM show 259. He didn't want an actual useful estimate, he wanted the car to tell him what he wanted to hear regardless of the reality of the situation. Ok, that's turning in to a rant, moving forward...

So it's just incredibly refreshing to see someone look at the situation, do a little experimenting, and say "Ok, it is how I drive. I'll live with that." Oh it just felt good to read that.

Thank you for sharing it and I hope others fine it helpful when the Fall brings around the range reductions for a whole new group of owners. Or even just someone about to take a road trip who thinks they are going to get the same 5 miles per kWh they get in the city on the highway. Who knows, you might just save someone from getting stuck plugged in to a 120v outlet at a gas station and swearing off EVs.
 

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Discussion Starter · #8 ·
I paid particular attention to my drive today. Most of the 50 miles is on "high speed roads" I live on a Texas Ranch to Market road (RR 165), the speed limit is 60 or 65 on that road. From there I drive on 290 to Austin. From Henly to Dripping Springs the speed limit is 65. (Remember this is Texas and 5 over the speed limit is normally the minimum acceptable speed.)

After Dripping Springs there is a awful stretch of 290 that has a large number of what A&M call "High speed traffic signals". So the speed limit is 55 and at any moment you will top a hill to see a red light. 290 slows down a lot in Austin until it becomes a freeway, for there to work is all freeway with 60-70 mile speed limits. So I think probably 10 miles of my 50 mile drive is not high speed roads.

The Bolt hates RR 165. It's very hilly and has "the divide" on it. Normally the first five miles of that drive is 2.3 to 2.5 m/kWh. Coming home it's a little better because I am coming down the hill. Still normally I get numbers in the low 3s.
 

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One person even said that GM needed to include an option to always make the GoM show 259. He didn't want an actual useful estimate, he wanted the car to tell him what he wanted to hear regardless of the reality of the situation. Ok, that's turning in to a rant, moving forward...
I believe that was me. I don't want it personally. I just think it should be an option for those who cannot understand how range meters work. As @GeneL makes clear, there is nothing wrong with the Bolt. But folks who insist on a promised number will always be frustrated and blame the car.

ga2500ev
 

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A long time ago I had an SVT Contour that averaged ~23mpg. I had a 15+ mile one-way almost all highway commute everyday. I made a set of rules to see exactly how good of economy I could do. No hard accelerations. Do not exceed 60mph and do not exceed 3500rpm in any gear. Started with a full tank and followed these rules until it was empty. This basically meant staying the the far right line of a 6 lane divided highway at all times. Many times in rush hour I could use the left lane safely without breaking my rules. The result. ~30mpg. While a 23-30mpg is a very good increase it was not worth the significant change in driving style to achieve.

The Bolt on the other hand is much easier to alter driving styles and still enjoy the drive.
 

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I believe that was me.
You may have said it, but you were not who I was referring to. If I would have seen you suggesting it I would have disagreed but recognize you understand the concept. No, that was someone else a while ago who no matter how often it was explained just never understood that they weren't filling the battery with "miles" 😅 (and no, not anybody recently active, this truly was some time ago)
 

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I asked how people got so much higher m/kWh than I did. The discussion starter said he got 4.4 to 4.6. I almost never see more than 3.9 so I was wondering if something was wrong with my Bolt.
Note: This is just my opinion. Feel free to have opposing opinion.
There's nothing wrong with you. You treat your car like a car. Others treat the Bolt like it's an efficiency challenge and they are blocking traffic and possibly causing accidents behind them that they never know about because people who drive like that get tired of worrying about the fast approaching cars behind them and they tune-out the rear-view mirror during normal driving. I've been a passenger with one of these slow-movers and noted that their eyes neve leave the road in front of them. The one other Bolt I've seen on the freeway I had to move around because they were driving 65 in a 75 zone with light traffic.

I did have to drive a little below the speed limit once since I was trying to stretch to a charger for intentional low charge to check battery capacity. I hated it. At one point a truck came on the freeway and had to slow down to squeeze in between me and a Semi and he proceeded to immediately, and not entirely safely, change into the next lane to get around me. All I could do is apologize in my head and promise not to do this again unless absolutely necessary.
 

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FWIW, here's the efficiency map of the Bolt's motor, from Electrical Propulsion System Design of Chevrolet Bolt Battery Electric Vehicle (DOI: 10.1109/ECCE.2016.7855076 — the DOI is useful for downloading the paper on sci-hub if you don't have access some other way).

What you see from this diagram is that pulling a ton of torque at really low speed isn't very efficient, but once you're moving even at a few miles an hour, it really doesn't matter much if you're demanding lots of torque.


35576
 

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I believe that was me. I don't want it personally. I just think it should be an option for those who cannot understand how range meters work. As @GeneL makes clear, there is nothing wrong with the Bolt. But folks who insist on a promised number will always be frustrated and blame the car.

ga2500ev
If I am not mistaken Tesla displays EPA rating * SoC (in kWh), then adjusts as you drive? If so, in effect, this is what the suggestion would do (always display 238 or 259). The added benefit would be at 100% SoC. you would tend to see a picture of what the real capacity\degradation status is.
 

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Having said all that, everyone has the right to drive how they feel comfortable. Its truly not a race. I would just prefer they feel comfortable in the right lane... :)
That isn't true at all. It's unlawful to be an impediment to the normal flow of traffic and a ticketable offense. In Oregon, there is a legal requirement to pull off to let faster traffic pass.

I've got extremely good emotional control, but the last holdout for me is traffic. I'm always yelling to myself "if you are too scared to drive, stay home or get someone else to drive you!?". I age by years when I'm stuck behind someone wanting to do 25 MPH below the speed limit.

My commute (now only once every few months) is 130 miles round trip. My best round trip efficiency was 6.5 mi/kWh, it averages 5.2 including cold CO winter driving. I know, I tracked it for 3 years!

I literally live at the top of a hill, at 7500 feet elevation. My office is at about 5000 ft.
There's a sizable gain in efficiency by living at elevation in the thinner air.
 

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I am familiar with the concept as my 2014 chevy cruze diesel had the same basic function. after fueling the tank to full it would indicate how many miles you could go based on the way you drove previously. I do believe this is the way that most modern cars work. But I don't know for sure as I only have experience with my cruze.

Even when I was driving 160 miles per day and I was honing my hypermiling techniques I was able to squeeze 680 miles out of a tank. My next fill up showed about 650 so there were limits to how far it would adjust. This was way more that the advertised MPG that the cruze diesel was rated at.
 

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I age by years when I'm stuck behind someone wanting to do 25 MPH below the speed limit.
Something you encounter at every on-ramp?

Seriously, people buy fast cars but then do not want to press the accelerator down more than 1/10 of the way when it is actually desirable to do so to merge into freeway traffic.
 

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Discussion Starter · #18 ·
you might appreciate this graph
They are interesting graphs. I think I need more information about the ICE one to really understand it. The EV one is much earlier to figure out.
the majority of time maintaining speed. Overcoming drag.
Yeah, slowing down is probably always the best way to increase range. So, the Bolt is not all that aerodynamically efficient (I have seen a figure of 0.32.) Apparently, the Model 3 is much more efficient at 0.21. I suppose that funny looking nose contributes, but I really don't like the look. (For some reason it makes be think of a duck that has been punched in the face.)
 

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I've got extremely good emotional control, but the last holdout for me is traffic. I'm always yelling to myself "if you are too scared to drive, stay home or get someone else to drive you!?". I age by years when I'm stuck behind someone wanting to do 25 MPH below the speed limit.
Where I live, there are some curvy mountain roads, but the curves aren't that bad and any modern car can take them at 45 mph or more, yet some people will slow right down. I do try to find amusement in the situation, imagining how exciting and filled with danger the world must seem to them. It doesn't remove all the frustration, but being able to laugh about it does help a bit.

Seriously, people buy fast cars but then do not want to press the accelerator down more than 1/10 of the way when it is actually desirable to do so to merge into freeway traffic.
Okay, this one does bug me. I actually try to give merging cars in front of me lots of gap just because I know some people will merge at a snail's pace and I don't want to be caught right behind them. In an ideal world, I can get enough of a gap that I can merge at normal speed even while they're still merging at a crawl.
 

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Seriously, people buy fast cars but then do not want to press the accelerator down more than 1/10 of the way when it is actually desirable to do so to merge into freeway traffic.
A lot of TX folks relocate to CO to escape the heat. My experience with highways in the Houston are is a lot of frontage roads with short on\off ramps that can be difficult to use. Around here, most on\off ramps have long merge or exit lanes, kind of the modern standard for interstates I suppose.

So when I get behind someone not accelerating up to prevailing speeds, or even slowing or stopping when entering freeways, I tend to yell out "Go back to Houston". Of course, nobody outside my car hears it, but it gives me a moment of relief.
 
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