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Does the Bolt have too much range?

Does the Bolt have too much range?

I know that most people will disagree with me, but I think the Bolt has too much range. I know most, especially first time, electric car drivers want as much range as they can get, but really, what is it used for?

The Bolt makes a good city car. Most drivers drive well under a hundred miles a day. Getting down to this number by removing battery weight would increase efficiency.

The Tesla can use its range for long distance travel but the Bolt, without a supercharger network, really cannot. You could drive to a destination within 200 miles as long as you have access to an L2 charger and the ability to leave the car there overnight. Otherwise you could only travel about a hundred miles away from home. Less if you want to drive anywhere once you get there.

Without ubiquitous high speed charging, I don't see the ability to travel so I see the extra range as useless. It is good for marketing though as no one would be talking about it if it had 100 mile range.

SamO | 04. april 2017

This popcorn is delicious . . . munch . . . munch.

Carl Thompson | 04. april 2017

NKYTA:
"Oh, so the math behind evtripplanner is now completely suspect? Because it is 'on the internet'?"

The math is suspect because I have common sense. I tested out evtriplanner with two identical trips with two different weights: 0 lbs and 20,000 lbs (10 tons). That site said the mi / kWh of the trip only drops from 3.4 to 3.0 when your Tesla is loaded with an extra _10 tons_ of weight.

Does that seem believable to you? Try critical thinking, please.

Carl

KP in NPT | 04. april 2017

Did you try out those trips with the weight differences to see if evtripplanner was BS and provide data backing up your claim or is it just a "feeling?"

Bighorn | 04. april 2017

So does common sense answer the question whether it is possible for a human being to pull a 189 ton airplane? Obviously, a Tesla lacks the suspension to carry 10 tons--not sure where you're hung up on the physics of propelling a weight on level ground though. Kind of silly to contemplate border cases when you can't comprehend the elementary physics. I know why--it's called diversion or, in politics, pivoting.

SamO | 04. april 2017

Delicious. So salty. Munch. . .

Carl Thompson | 04. april 2017

@Bighorn

Sure a person can pull a plane. You may not find the acceleration or range reasonable, though.

And would that person have the same energy economy (miles / kilo-calories burned) pulling that plane as they would pulling a rickshaw? Common sense should tell you "no."

Carl

KP in NPT | 04. april 2017

I highly recommend Trader Joe's Baconesque popcorn. It's like crack.

dyefrog | 04. april 2017

KP, would you pass the salt please? Do we have more butter?

Red Sage ca us | 04. april 2017

Some of the best popcorn known to mankind:

Crunch & Munch
http://www.food.com/recipe/crunch-and-munch-63443

Fiddle Faddle
http://www.food.com/recipe/fiddle-faddle-popcorn-504386

JayInJapan | 04. april 2017

"seem" "believe" "common sense" = truthiness

Bighorn | 04. april 2017

Has Carl convinced anyone with his incisive logic? I'm not sure what else to say. Fake news?

SamO | 04. april 2017

I'm enjoying the time you are taking, while you draw and quarter. Such precision. Surgeon?

Munch.

KP in NPT | 04. april 2017

SamO lol!!!

Carl Thompson | 04. april 2017

@Bighorn @SamO @KP

I'll just remind you of what Bighorn said:
"...an unladen Model 60 on 19" wheels will use 123.9 kWh whereas the same car carting around an extra ton will use 124.0 kWh or 0.08% more energy i.ei 1.0008 times more energy. NOT a BIG difference,"

But, hey, believe what you want. If you want to believe that adding an extra 2,000 pounds to a model S only only uses 0.0008 more energy then I have a bridge to sell you.

Carl

KP in NPT | 04. april 2017

You still haven't proven your work.

4fishtankz | 05. april 2017

because of the length of time to charge without supercharging, having the range without that capability would mean the car will be out of commission while it's charging and if you don't have enough range to get to your next destination. Having too low of a range will mean if you want to make multiple trips you'll have to take that into account and if you'll need to charge in-between.

Even though most people's commutes to work may be short enough to justify a lower range, a lot of people do not factor in what they drive outside of work and weekends. Do you want a second car to do that when your electric car falls short on range? My commute to and from work maybe around 15 miles, but I do like to go to outlying areas for errands and just drive on the weekends. Also, if you have a home charger and need to charge in the middle of the day, you maybe hit with peak charge electric rates. Also, lower range means higher range anxiety.

I found that owning a electric car I had to plan trips, combining and only going around half my range so I could come back and charge. If I found a charger or could plan on charging close to where I was going, great, but I didn't always count on it. Lower range cars you feel you are chained to the plug more.

DTsea | 05. april 2017

Carl Thompson i will help you out with a 'common sense' type point.

Weight of the vehicle at constant speed doesnt drive energy consumption. Coefficient of drag and speed are primary, folliwed by rolling resistance.

Trains for example are super efficient. Although it takes a lot of power to get them moving, steel wheels on rails have very low sensitivity to weight in rolling resistance and the Cd of a train is excellent because (aerodynamically) it is a very long and slender object.

For a car at constant highway speed on rubber tires there is more sensitivity of rolling resistance to weight because of contact patch area. But practically speaking within the weight allowance of the car (about 800-1000 lb of payload) relative to tare weight (about 4800 lb) rolling resistance is small relative to aero drag. Best tactic to improve power use is to slow down a bit.

I would speculate that evtripplanner uses weight to calculate power to climb hills- where it DOES matter- but not for the tertiary effect of rolling resistance where each passenger adds only about 4 to 5 percent to vehicle weight. I say this because of the reported small drop in level, constant speed, energy use from the app with impossibly heavy payload weight. When climbing, or in city driving, weight does matter more.

bmalloy0 | 05. april 2017

DTsea, thanks for the explanation!

Carl Thompson | 05. april 2017

DTsea:
"Weight of the vehicle at constant speed doesnt drive energy consumption. Coefficient of drag and speed are primary, folliwed by rolling resistance."

Yes, I get that. That's why I didn't list drag as one of my factors. But wheel / road friction (sorry rolling resistance the correct term) _is_ weight sensitive.

But you are also now adding a qualifier that is unreasonable: "at constant speed." Cars do not move at a constant speed. They must constantly accelerate, "decelerate" and turn (change direction). All can be though of as applying acceleration along a different vector and all require energy. Either you are adding energy from the battery or losing kinetic energy via friction and the energy added or lost for all is proportional to weight. All of the energy ultimately comes from the battery.

So when bighorn says that a Model S loaded with an extra 2,000 pounds only uses less than 1/1,000 (0.0008) more energy on a trip that is obviously false on its face and I believe anyone with common sense _should_ be able to see that.

Bighorn:
"...an unladen Model 60 on 19" wheels will use 123.9 kWh whereas the same car carting around an extra ton will use 124.0 kWh or 0.08% more energy i.ei 1.0008 times more energy. NOT a BIG difference,"

Carl

DTsea | 05. april 2017

Eagles you seem not ro have read my post. Yes weight matters for acceleration and climb. Weight matters for astop and go becaise regen has losses, althoigh weight matters less in an EV than an ICE because of regen.

I was explaining to Carl the effect of weight at CONSTANT SPEED.

EaglesPDX | 05. april 2017

" Yes weight matters for acceleration and climb."

Weight matters all the time. It takes constant energy to keep pushing the weight. There will be very little air resistance at low speed but the weight is the constant that requires energy to move.

Again one can see this easily in the Tesla's where the smaller battery in the same car gets more miles per kWh TS75D 3.45 miles per kWh
TS90D 3.26 miles per kWh

Musk has explained this several times to people who keep saying put in 200 kWh battery.

DTsea | 05. april 2017

No eagles. A body in motion remains in motion unless resisted by an opposing force. Basic newtonian mechanics/laws of motion.

At constant speed on level ground, resisting forces are aero drag (shape only), rolling resistance (slightly sensitive to weight).

You keep confusing power to accelerate the car, which is sensitive to weight, with power to keep the car moving, which is not.

Bighorn | 05. april 2017

Apparently Eagles is an eighth grade drop-out.

Regardless, Carl's assertion that weight is a BIG factor in efficiency is patently false.

I wonder if either of them have ever coasted in neutral in a Model S. It's uncanny--to me it feels like it's accelerating, and it is sometimes on imperceptible descents. The other thing to consider is that a heavier car has more inertia and therefore contributes more to regenerative gains than a lighter car.

Thanks DTsea for trying as well!

Carl Thompson | 05. april 2017

DTsea:
"I was explaining to Carl the effect of weight at CONSTANT SPEED."

Cars do not operate at constant speed in real life.

Carl

Bighorn | 05. april 2017

Most places I've driven with cruise control allow unfettered access to constant speed. Since we had eliminated stop and go traffic and elevation gains from the conversation, that would be highway driving in my mind. Regeneration helps mitigate any losses for unplanned slow downs. Give up--you were wrong.

Frank99 | 05. april 2017

The drive from Phoenix to LA is the definition of flat, and constant speed. I wouldn't expect weight to have a huge impact on the range of an EV with good regeneration (but I'd expect more than EVTrippplanner estimates). Rolling resistance is going to go up with weight.

Even in stop-and-go city driving up and down hills, weight will have far less impact on a good EV than it has on an ICE because of regeneration.

Carl Thompson | 05. april 2017

Bighorn:
"Regardless, Carl's assertion that weight is a BIG factor in efficiency is patently false."

I see. So you are no longer claiming "0.08% more energy" or " obviously small difference based on weight?" Now you're just saying it's not a BIG factor?

So let's get back to my original example that caused you to make the statements from which you're now backing away.

Me:
"Weight could easily be a big difference. For example the much heavier 3.5mi/kWh Model S is less efficient than my 4mi/kWh BMW i3 even though the Model S has a lower drag coefficient (0.24 vs. 0.29)."

To which you said

Bighorn:
"I'm talking physics--you're talking two different models from two different companies."

Physics actually doesn't care whether cars are "two different models from two different companies." So you have the following choices that I see:

1. Admit that I was in fact correct and weight is enough to make this difference despite the Model S CoD advantage

2. Argue that because the i3 is a different car made by BMW the difference comes from the fact that BMW batteries, motors, inverters, regenerative brakes and / or tires are so much more efficient that it's enough to account for this

3. Claim that you didn't actually say or mean what you said. Delete the posts where you said it so no one knows

4. Claim victory without any facts or logic to back you up. Just talk about how coasting in a Model S "feels"

5. Parse the definition of the word "big" so that you can claim that it doesn't mean what I defined it to mean in my comment

You seem to be going with a combination of 4 and 5 so far. I'd suggest adding in a little 3 too.

Carl

Bighorn | 05. april 2017

I'm simply using appropriately small words for my intended audience. You are welcome to argue with Ben Hannel over his underlying equations on evtripplanner. You have summarily dismissed his data. Please provide your own data that would qualify weight as having a "big" effect. I did suggest earlier that you might resort to parsing the meaning of "big" as others have done with "comparable." You certainly seem to have enough time on your hands--why have you provided no evidence to support your claim? Your buddy Eagles has said as much but qualified it with the required "at low speeds" where aerodynamic drag becomes much less critical. Unfortunately, we weren't really discussing low speed driving. Another point you seem oblivious to is that coefficient of drag is not something you can use to compare cars without factoring in the frontal areas.

SamO | 05. april 2017

My god. This may be the. Best. Popcorn. Ever.

KP in NPT | 05. april 2017
Carl Thompson | 05. april 2017

Frank99:
"Even in stop-and-go city driving up and down hills, weight will have far less impact on a good EV than it has on an ICE because of regeneration."

I agree with everything else you said but not this. Regenerative brakes are only able to recover a small amount of the kinetic energy lost when braking. According to what I've read regenerative brakes only improve energy efficiency about 15%-30% over just using friction brakes.

- www.mate.tue .nl/mate/pdfs/12673.p d f
- https://www.researchgate .net/publication/252050989_Analysis_of_regenerative_braking_efficiency_-_A_case_study_of_two_electric_vehicles_operating_in_the_Rotterdam_area
- http://large.stanford .edu/courses/2016/ph240/brown1/

Carl

Carl Thompson | 05. april 2017

Bighorn:
"Please provide your own data that would qualify weight as having a "big" effect."

I already have, 3 times. Your Model S gets 3.5mi/kWh and my much lighter BMW i3 gets 4mi/kWh despite the Model S have a CoD advantage. That's what we are talking about. These real-world numbers support what I said and don't support what you said.

I'll check back in to this topic if you ever actually address that.

Carl

topher | 05. april 2017

"The other thing to consider is that a heavier car has more inertia and therefore contributes more to regenerative gains than a lighter car."

Nope. The kinetic energy is 1/2 * M * V^2. You get more out of a heavier car, because you put more in. If anything a heavier car might produces a lower percentage of that energy as regenerative braking, should it exceed the power limit on the system.

Thank you kindly.

Bighorn | 05. april 2017

@topher
I was talking about cars at speed--not globally. Don't you think a heavier car would coast farther and give a higher return of regenerative energy? Obviously, it takes more energy to get up to speed, but some of that is being recouped.

EaglesPDX | 05. april 2017

"A body in motion remains in motion unless resisted by an opposing force."

It's called gravity.

KP in NPT | 05. april 2017

LMAO!!!!!!!!

licking my buttery fingers.....

Bighorn | 05. april 2017

@Eagles
Quit while you're behind.

KP in NPT | 05. april 2017

BWRAHAHAHAHA I'm dying!!!

Frank99 | 05. april 2017

No, that's called a truncated version of Newton's First Law of Motion.

Gravity (for the high schoolers) would be "a particle attracts every other particle in the universe using a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres." We won't get into higher education levels of gravity.

But what does that have to do with the effect of weight on range?

Frank99 | 05. april 2017

By the way, Carl, thanks for the links. I'm not quite sure that they back you up, but you have plenty of people to argue with here already.

Carl Thompson | 05. april 2017

@Frank99

Each of the articles in those links seemed to indicate that regenerative breaking increases energy efficiency by about 20%. The widest range of the 3 was 15%-30%.

But this is definitely not my area of expertise.

Carl

DTsea | 05. april 2017

Eagles.... gravity is perpendicular to the velocity vector on level ground and has no component resistive to forward motion.

Carl... constant speed = cruise control. I use it every day.

SamO | 05. april 2017

When you find yourself in a hole, the first thing you should do is stop digging.

I've switched over to kettle corn.

Bighorn | 05. april 2017

Total pivot obviously, but I'll bite. So if an 80% efficient electric car gains a 20% improvement from regenerative braking, is it 100% efficient or "only" 96% efficient. And is that really just a small gain? Or is this new math?

Frank99 | 05. april 2017

Carl -
I only had a few minutes to look at them, but they seemed to be discussing an overall improvement. When large amounts of energy are taken up in aero drag, even a 100% effficient regen might not give a significant overall improvement.
My original statement assumed regen was highly efficient - that all (or 80%, or 70%...) of the extra energy you used to lift the car's weight up a hill would get regen'ed back into the battery on the way back down the hill. The same for stoplights - if most of the energy you need to accelerate back to speed was regen'ed slowing down to stop, you only pay a small penalty for stoplights. But, I freely admit, I have no idea what the real regen efficiency is, and your links are the only hard data I've seen for how regen affects overall efficiency.
But all these are simply indirect guesses at the original discussion, how much weight impacts range on an EV. And I don't know we're any smarter than we were this morning...

EaglesPDX | 05. april 2017

"Eagles.... gravity is perpendicular to the velocity vector on level ground and has no component resistive to forward motion."

If cars were riding on frictionless electrimagnetic cushions perhaps but alas, gravity pulls them down and there is the drag of the components, the gear boxes and motors even on zero regen and then there's the issue going uphill. Gravity is relentless and comes at you from so many directions.

But back to the Bolt's 238 mile range that has the Teslerati in a constant turmoil.

KP in NPT | 05. april 2017

Crack is whack.

topher | 05. april 2017

@bighorn:

Let's agree on some things:
Car A is twice as massive as Car B, but in all other ways identical.
We'll talk about physics 101 conditions.
Regenerative braking returns 50% of the energy. It is not limited by anything we will experience here.

Car A and Car B are both traveling at 100 kph.
Car A has twice as much kinetic energy as Car B (ke = 1/2 * m * v^2).
Car A regen will return twice as much energy as Car B.

So now they are both stopped. And accelerate back up to 100 kph.

Car A requires twice as much energy to get back up to 100 kph as Car B. You need to include all energy input and all energy output. So as a percentage of energy input, the energy output is the same (namely 50%).

Duh, that's what we took as a assumption in the first place.

Ok, so what could affect the rate of energy capture (power) in regen brakes?
The motors, wires and batteries all have power ratings. If the power level of the regen brakes exceeds those power limits, some of that power will need to be shed by heat into the brake pads instead of being regenerated. This is far more likely to happen in Car A, since the power is double that of Car B. [For a Tesla, this is probably not a problem since we know that the batteries can accelerate the car at near the emergency braking acceleration. I suspect that is not true of other EVs.]

I can't see any limitations which apply to Car B, that don't apply to Car A. Do you?

Thank you kindly.

topher | 05. april 2017

@bighorn:
"if an 80% efficient electric car gains a 20% improvement from regenerative braking, is it 100% efficient or "only" 96% efficient."

Nothing that simple. Let's account for all the energy losses:
1) Efficiency losses. Heat in the motors, Heat in the batteries, gear friction, etc. (this is what that 80% represents)
2) Non-motive energy uses.
3) Rolling friction.
4) Aerodynamic losses.
5) Braking heat losses.

Braking losses vary, of course, that's why city mileage is different from highway mileage. A 300 mile trip with no stops has negligible braking losses, while stop and go traffic will have very high losses. The 20% improvement for regenerative braking applies only to those losses. For example, if braking losses end up being 10% of the total losses, then a 20% regen of that is 2% of the total losses (and 82% overall efficiency).

Thank you kindly.

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