Chevy Bolt - 200 mile range for $30k base price (after incentive)

[SageBrush]

170 miles of range at top speed of 92 mph.

The drag equation says 415 Wh/mile for air and road losses at 92 mph, so perhaps 450 Wh/mile overall.

A 60 kWh usable capacity (is this true ?) would then return 60/0.45 = 133 miles if no other accessory use like AC.
And of course GM only warrants the battery after up to 40% of capacity is lost in the first 8 years.

So this advert could just as easy be "no less than 80 uncomfortable miles from a full charge at 92 mph (and then curse yourself for buying a car without the Tesla SC network.)"

 

[McRat]

The drag equation says 415 Wh/mile for air and road losses at 92 mph, so perhaps 450 Wh/mile overall.

A 60 kWh usable capacity (is this true ?) would then return 60/0.45 = 133 miles if no other accessory use like AC.
And of course GM only warrants the battery after up to 40% of capacity is lost in the first 8 years.

So this advert could just as easy be "no less than 80 uncomfortable miles from a full charge at 92 mph (and then curse yourself for buying a car without the Tesla SC network.)"

Which windtunnel did you use?

 

[Jeff N]

The drag equation says 415 Wh/mile for air and road losses at 92 mph, so perhaps 450 Wh/mile overall.

A 60 kWh usable capacity (is this true ?) would then return 60/0.45 = 133 miles if no other accessory use like AC.
And of course GM only warrants the battery after up to 40% of capacity is lost in the first 8 years.

So this advert could just as easy be "no less than 80 uncomfortable miles from a full charge at 92 mph (and then curse yourself for buying a car without the Tesla SC network.)"

As best as anyone can tell so far, the usable capacity is around 59-60 kWh. I personally am not willing to drive my car from fully charged down until it stops in order to verify that but people have come close to empty and reported 58.7 kWh or more.

Based on various other numbers I have seen (like Car&Driver's 190 miles at 75 mph), I think 170 miles at 92 mph sounds overly optimistic and I agree that 133-140 miles seems more likely. Since they were figuratively driving the Autobahn in Europe maybe they applied a NEDC adjustment to those miles. Or, maybe they actually drove the real autobahn but included slower segments near towns that have reduced speed limits?

Of course, Tesla doesn't warrant against range loss nor do they place traditional advertising so I guess, from that perspective, GM would own the bragging rights for battery range at 92 mph.

 

[Zoomit]

I think 170 miles at 92 mph sounds overly optimistic and I agree that 133-140 miles seems more likely.

I can get my Bolt EV driving efficiency model to show 170 miles at 92 mph, but I need to adjust the Cd down from 0.32 to 0.23.

 

[McRat]

If any vehicle is 190 mi @ 75 mph, it should be 109 miles at 92 mph. CdA and Cd do not come into play, only rolling resistance.

I think they screwed up. The testing and programming is all metric since the 1990's, so it was most likely 170 km not miles.

 

[Saghost]

If any vehicle is 190 mi @ 75 mph, it should be 109 miles at 92 mph. CdA and Cd do not come into play, only rolling resistance.

I think they screwed up. The testing and programming is all metric since the 1990's, so it was most likely 170 km not miles.

Huh?!?

Rolling resistance is nearly independent of speed when expressed in per unit distance terms. It's true that any level of Cd and CdA will experience the same percentage change between 75 and 92 mph, but the ratio of rolling resistance to aerodynamic drag and fixed loads at 75 will affect how much more energy is used at 92 mph...

Driving at 92 mph will require 50% more energy per mile to overcome aerodynamic drag - which means that a car with no rolling resistance or fixed loads (worst case) will go 66% the distance at 92 mph.

If a car can actually do 190 at 75 (which seems improbable for one that does 210 at an average of 48 mph but 250+ at low speeds in stop and go,) then I'm expecting 126ish, which would seem to agree well with the 133 someone got from a more detailed model upthread.

 

[McRat]

Huh?!?

Rolling resistance is nearly independent of speed when expressed in per unit distance terms. It's true that any level of Cd and CdA will experience the same percentage change between 75 and 92 mph, but the ratio of rolling resistance to aerodynamic drag and fixed loads at 75 will affect how much more energy is used at 92 mph...

Driving at 92 mph will require 50% more energy per mile to overcome aerodynamic drag - which means that a car with no rolling resistance or fixed loads (worst case) will go 66% the distance at 92 mph.

If a car can actually do 190 at 75 (which seems improbable for one that does 210 at an average of 48 mph but 250+ at low speeds in stop and go,) then I'm expecting 126ish, which would seem to agree well with the 133 someone got from a more detailed model upthread.

57%

Average speed is a joke used to promote bad science. 48 mph steady state is not the same. I can drain 6 kWh in <6 miles and never hit 60 mph ever. Average speed <30. We did it in two cars with raceweights of 3800lb on LRR tires 5 days ago.

 

[McRat]

Amazing, now people are disagreeing with High School math.

 

[Jeff N]

Amazing, now people are disagreeing with High School math.

Well, in any case, there seems to be consensus that the real answer is likely somewhere between 109 to 133 miles at 92 mph rather than 170 miles.

 

[McRat]

Well, in any case, there seems to be consensus that the real answer is likely somewhere between 109 to 133 miles at 92 mph rather than 170 miles.

It's easy to test. On a wind-free day, cruise control at 75 record avg kW. Do a return. Average the two. Do it at 92.

The kW if displayed accurately will take all factors into consideration. If 75 is 24kW then 92 should be 42kW if I got the rolling resisting correct. Or I could be way off.

 

[JRP3]

Or I could be way off.

From your history that seems the more likely conclusion.

 

[schonelucht]

It's easy to test. On a wind-free day, cruise control at 75 record avg kW. Do a return. Average the two. Do it at 92.

The kW if displayed accurately will take all factors into consideration. If 75 is 24kW then 92 should be 42kW if I got the rolling resisting correct. Or I could be way off.

At least you are consistently using the wrong terms. Rolling resistance is proportional to the weight of the vehicle, not speed. Aerodynamic resistance is proportional to the square of the speed. Total resistance is the sum of both and internal (friction) forces. Your earlier quote that Cd/CdA does not come into play when evaluating power use at different speeds is also incorrect. It does : Drag coefficient - Wikipedia

 

[McRat]

From your history that seems the more likely conclusion.

Every broken clock is correct twice a day.

Most my experience is from 150 to 200mph with very low rolling resistance on Mickey T "Bonneville Special" tires at 90psi inflation with a 7100lb raceweight. It tells me when to apply full throttle to get peak average speed over a 1 mile segment. You do not hammer it off the start.

But we also did lower speeds on my son's Volt for a Science Fair project. He graphed kW used from 35mph to 70mph. It came out about where the calculations predicted.

Feel free to test it yourself. Calculations are where you start, testing is where you finish.

 

[McRat]

At least you are consistently using the wrong terms. Rolling resistance is proportional to the weight of the vehicle, not speed. Aerodynamic resistance is proportional to the square of the speed. Total resistance is the sum of both and internal (friction) forces. Your earlier quote that Cd/CdA does not come into play when evaluating power use at different speeds is also incorrect. It does : Drag coefficient - Wikipedia

You do not understand. The percentage of power increase required to drive faster is not dependent on CdA or Cd, but it is dependent on % of rolling resistance.

 

[Topher]

You do not understand. The percentage of power increase required to drive faster is not dependent on CdA or Cd, but it is dependent on % of rolling resistance.

Which might be valid if that was what you actually wrote. Don't complain about people not understanding what you mean, when you don't write what you mean.

Thank you kindly.

 

[schonelucht]

You do not understand. The percentage of power increase required to drive faster is not dependent on CdA or Cd, but it is dependent on % of rolling resistance.

I think I understand what you mean, but you could have worded that (and this) phrase much clearer. I suspect you meant to say : the increase in power required to drive faster depends on how much of the power necessary to drive at the lower speed is due to rolling resistance. Which is indeed correct.

 

[Saghost]

You do not understand. The percentage of power increase required to drive faster is not dependent on CdA or Cd, but it is dependent on % of rolling resistance.

Put that way, what you are saying makes sense. I certainly didn't get that from your original post on the subject when I read it.

 

[jgs]

current Tesla owners will surely make an effort to quietly communicate early problems to Tesla

Have you read any of the other threads on TMC?

 

[McRat]

Put that way, what you are saying makes sense. I certainly didn't get that from your original post on the subject when I read it.

We need actual data to have a real answer.

But I'll put my money on 109 mi for now.

 

[JRP3]

Bolt review from "biased" electrek The Electrek Review: 2017 Chevy Bolt EV is the first Plug-in for everyone

The Bolt is unequivocally the best $30,000 EV you can buy today (in some states + Canada) and for my money, the best car of any kind on the roads right now at its price point. GM/Chevrolet deserve a mountain of praise for delivering the first affordable EV with more range than anyone could hope to use on a daily basis.