Woke electric vehicles BREAK records ! !

[Ed P]

I'd plan my route to be all down hill so I'd use the brakes a lot.

[Bob F]

Not usually, I believe. Electric motors have best torque at zero RPM, and electric motors can be designed to have a very wide RPM range.

Here's an interesting discussion.

[Bob F]

This seems pretty silly. Regen braking does not recover as much energy as is used to accelerate back up to speed. The real reason they might be more efficient in the city is because they are driving slower, since air drag increases with the square of the speed.

Which will waste more power.

[Scott Lurndal]

Every source I've found, including government agencies agree that regen is the primary reason that range is greater in urban environments vs. long-distance travel.

Think about it. Absent entropic losses, every time you brake, you recover much of the energy used to accelerate.

[invalid unparseable]

No, Bob F and I are correct and we have thought about it. micky thinks if you do it at highway speed you will get city mileage. You both have to think about it and not parrot erroneous writings.

[Bob F]

But if you do not brake, you don't lose ANY of it. Silliness!

[Bob F]

"Efficiency of the regenerative braking process varies across many vehicles, motors, batteries and controllers, but is often somewhere in the neighborhood of 60-70% efficient. Regen usually loses around 10-20% of the energy being captured, and then the car loses another 10-20% or so when converting that energy back into acceleration, according to Tesla. This is fairly standard across most electric vehicles including cars, trucks, electric bicycles, electric scooters, etc."

[T]

Frank,

I do not think they realize that to recover energy, you have to decelerate without breaking (foot off the accelerator), otherwise that energy goes into heat on the brake pads. And since BEV's are twice as heavy as ICE, those breaks are pretty hunking big.

Oh and if your battery is pretty fully charged, you won't get much deceleration. The load on the secondary is reflected into the primary. No load, no breaking.

-T

[invalid unparseable]

I suspect they understand now but do not expect them to admit it.

[Scott Lurndal]

I expect that neither of you know what you're talking about. Which is normal for T.

Regenerative braking - you've probably heard the term before, but you may not know what it is or how it works. If so, you're in the right place. In this guide, we'll cover what regenerative braking is, as well as its advantages and disadvantages. What Is Regenerative Braking and How Does it Work? Regenerative braking is a mechanism found on most hybrid and full-electric vehicles. It captures the kinetic energy from braking and converts it into the electrical power that charges the vehicle's high voltage battery. Regenerative braking also slows the car down, which assists the use of traditional brakes. In a conventional braking system, a car slows down due to friction between the brake pads and rotors. But this system is highly inefficient when it comes to conserving energy. Nearly all of the kinetic energy propelling your car forward is lost as heat when you apply the brakes. That's a lot of wasted energy! Regenerative braking solves this problem by recapturing upwards of 70% of the kinetic energy that would otherwise be lost during braking. The amount of energy recovered depends on your car model and driving behavior. ...

Even though regenerative braking provides a lot of stopping force on its own, EVs and hybrids also come with conventional hydraulic brakes. However, since regenerative braking does much of the work while slowing the vehicle, the brake pads and rotors are used much less frequently.

...

In more technical terms, the brake system in a hybrid or electric vehicle applies reverse current to the motor, which opens the charging circuit. The EV's computer system determines the amount of 'brake' getting applied from the backward running motor, thus decreasing the speed until the vehicle comes to a stop

... Though usually regenerative braking only adds 10-15% more range with city driving and a negligible amount with highway driving, under optimum conditions such as an extended trip downhill, regenerative braking can recharge your vehicle up to 50%.

[invalid unparseable]

We know all this. You still cannot grasp the fact that lower highway mileage is caused by higher air resistance.

[Scott Lurndal]

What added air resistance? The EVs are specifically designed to be low drag, better in general that most vehicles by far. Their weight is comparable to any luxury sedan.

And who said anything about mileage? The discussion is about range, and the largest element of the increased range in city driving over highway driving is the effects of regenerative braking.

[T]

[T]

Bite me comrade.

The air resistance is proportional to the square of the velocity you are raveling through it.

Oh, and the energy you capture from using the motor to break you is lost to the energy required to re-accelerate you backup up to speed.

There is no place in science / engineering for political dictated outcomes.

[invalid unparseable]

Yes, one of our biggest problems are allowing politicians to do this. I read that 21% of the US is illiterate and have long suspected it is much higher when it comes to science and engineering.

[T]

No fooling! And it does not help that the woke claim they are "science", which they are anything but. Trofim Lysenko lives!

There are so many exciting things in our future with cars it is mind boggling.

Hydrogen and natural gas fuel cells. The ever improving internal combustion engine. Thing we have not yet thought of.

But they will be suppressed for political purposes, meaning supporters will get their palms waxed and useful idiots will get to virtue signal.

BEV are a pollution nightmare. I look forward to their becoming a niche only market. That being said, the choice of the technology should be set by the market, not corrupt politicians.

[Ed P]

Absolutely, that is how politicians get elected.

“I love the poorly educated”, announced Trump in a jubilant speech as he swept to victory in the Nevada caucus.

“We won with young. We won with old. We won with highly educated. We won with poorly educated. I love the poorly educated.”

[Bob F]

I think the difference in "range" is the lower speed of driving in the city. The regenerative braking increases that. It does nothing for long distance driving. I am sure, that if you drive at city speeds on the highway, you will exceed the mileage of city driving, because you will not have the energy losses of stopping and starting.

[rbowman]

We can agree on that. How many of the alleged 81.3 million Biden voters would you trust to clean your house unsupervised without managing to burn it to the ground, steal everything you own, or both?

I'm not saying the 74.2 million Trump voters are any better but isn't it grand the figureheads are chosen by counting noses of people, many of whom have made shambles of their own lives?

I say figureheads because the nation survives by a horde of more or less faceless bureaucrats who were never elected. It survived Trump and it seems to be surviving the listless vessel that is the Biden administration.

[danny burstein]

[everything snipped]

Look everyone, the vast majority of posts in this thread are from people who, bluntly, don't have a clue.

So... as someone here who actually owns and keeps records on our hybrids, one of which is a PHEV (none are "pure electric"), here's the deal:

Cars, whether gas or electric, get better mileage at lower speeds. With a gasoline car, this will reverse at, more or less, 15 mph because there's plenty of, loosely speaking, "overhead" just keeping the gas engine, etc., running.

(BIG NOTE: there are complications courtesy of transmissions and gear switching, but let's leave that out for now)

With electric cars this isn'e an issue.

As you speed up, mileage gets _less_ because air resistance increases as the _square_ of the speed bump. So if you've sped up from 25 mph to 50, you've got _four_ times the air resistance.

Yes, most cars today are more "slippery" (technically the "drag coefficient" is better - they're more aerodynamic), but they ain't perfect.

(Rolling resistance - that is, the tyres versus roadway, is more a 1:1 increase)

Net result: cars get better mileage, whether it's per gallon of fuel or per kw-hr of electricity, when driving more slowly.

(Anyone else remember the reason President Nixon mandated the 55 mph speed limit?).

So cars driven at _city_ speeds of 30 mph will, except for one problem... get better mileage than those doing 70 on the highway.

HOWEVER, city traffic has lots of "stop and go". And with a gasoline car, each stop takes all that momentum and, so to speak, uses it up to heat the brakes, etc. And then the car has to accelerate again, wasting all that energy.

So... in city "stop and go", the gasoline car will see its net mileage drop.

This is where the electric cars (hybrid, PHEV, or fully..) err, pull out way ahead.

Instead of all that energy going bye bye, the cars "reverse" the electric motors, turn them into generators, and capture the momentum and pump it back into the batteries.

(Note this is NOT perfect, and a fair amount is lost, but they still do a hell of a lot than gasoline veh's which just waste it all).

So net result:

At steady highway speeds, both types of veh's will do worse than at city speeds.

In city _steady_ speeds, they'll both do better. BUT in stop and go, which is the case for most city street driving, the electric veh's pull way ahead of the fossil fuels.