Regenerative braking?

anotherkiwi

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Jan 26, 2015
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Wanna bet? :D

You've never seen me really drive hard.
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Oh you naughty Italian person! :D

When I am in the Spanish bit of Spain I always explain to passengers not to be surprised if my driving becomes slightly more aggressive. After many visits I found it was easier to drive like them to fit in the flow of traffic. The mother of my two youngest said one day "you can't turn left here it is forbidden" to which I replied "we have been turning left here all week... and the three cars in front just did too right now"

Back on topic!

On a velomobile site (bent rider???) a Swiss guy explained that he doesn't charge at home because his drive to work is all down hill and with regen the battery was never emptied. He gets to work and tops up the missing 30% for the ride home which empties the battery.
 
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flecc

Member
Oct 25, 2006
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Well to stay on topic..
In the manual for my last car it said something about regenerated energy from braking was stored as an over voltage in the battery for use when required. Or sumsuch.
I could never understand how that ciuld work.
Doesn't make much sense on an average ic car.

Suzuki now have strange regen system on at least one model. They have a crankshaft speed starter motor that regenerates on the overrun to charge a little lithium battery under the front passenger seat. That battery current is then put back into the starter motor to assist the engine in the following acceleration. Like a mini KERS system. From what reviewers say it seems to work to some degree.
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Woosh

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May 19, 2012
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Google being Google and with me typing Audi in a few times it has shown me this report which I find interesting because I thought the leaf did this anyway... or is it just gobbledygook?
http://www.alphr.com/cars/1009779/audi-e-tron-solved-ev-range-regenerative-braking-charging
quote from that article:

"In reality, nobody is going to go and seek out a hill to eke out a few more miles as they drive, but it’s a great example of just how effective the regenerative braking technology seems to be."

For average use, if you have regenerative braking, you can expect about 4%-5% saving on energy. That is not because the circuitry is not efficient, it's because you don't brake as often as you keep your foot on the accelerator.
 

Gubbins

Esteemed Pedelecer
quote from that article:

"In reality, nobody is going to go and seek out a hill to eke out a few more miles as they drive, but it’s a great example of just how effective the regenerative braking technology seems to be."

For average use, if you have regenerative braking, you can expect about 4%-5% saving on energy. That is not because the circuitry is not efficient, it's because you don't brake as often as you keep your foot on the accelerator.
Yes but it's making it out to be something new, revolutionary even.
 

Woosh

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May 19, 2012
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Yes but it's making it out to be something new, revolutionary even.
that article reads a bit like an 'editorial advert'.
In the pre-internet days, I used to place my PC ads on the 'right hand page facing matter', a euphemism for placing the ad where my PC review was printed. Terms like 'ground breaking' were frequently used in reviews then.
 

flecc

Member
Oct 25, 2006
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Google being Google and with me typing Audi in a few times it has shown me this report which I find interesting because I thought the leaf did this anyway... or is it just gobbledygook?
http://www.alphr.com/cars/1009779/audi-e-tron-solved-ev-range-regenerative-braking-charging
That's total rubbish, the Leaf for one has always done this. My routine braking never engages the pads, even in normal mode it's all done by the drag of the motor regenerating on the overrun.

If I flick the puck into B mode it multiplies the regen, feeling like a giant hand grabbing the car to hold it back. All with no brake pad engagement.

The proof is that owners report the brake pads almost never need renewal, since with normal driving they are only used for emergency braking.
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Gubbins

Esteemed Pedelecer
That's total rubbish, the Leaf for one has always done this. My routine braking never engages the pads, even in normal mode it's all done by the motor regenerating on the overrun.

If I flick the puck in B mode it multiplies the regen, feeling like a giant hand grabbing the car to hold it back. All with no brake pad engagement.

The proof is that owners report the brake pads almost never need renewal, since with normal driving they are only used for emergency braking.
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Which is what I thought.. so how can Audi advertise this as innovative?
 

flecc

Member
Oct 25, 2006
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Which is what I thought.. so how can Audi advertise this as innovative?
It's called marketing, relying on public ignorance. Remember, Audi is VW, the emission cheats, crime against consumers is nothing new for them. The EU has heavily fined them three times for price fixing, first €4 millions, then when repeated three years later, €31 millions, and in the latest case involving their Scania truck company, a massive €880 millions.

If you get a chance sometime, beg a Leaf test drive. You'll discover the normal gentle braking of regen on lifting off, and by flicking back the drive puck to B mode, you'll find how strongly that brakes. It's too strong for holding the car at 30 mph on a 10% downhill, slowing it down, just balancing it at 30 on a 15% downhill.

Here's further proof that regen does the normal braking. On my new Leaf there's the choice of using e-pedal instead of normal two pedal driving. In that mode lifting off a little does the usual regen braking, lifting off further applies the brakes as well.

If that was similar to what it did usually as Audi claim, why would it now be provided as a choice?
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Gubbins

Esteemed Pedelecer
It's called marketing, relying on public ignorance. Remember, Audi is VW, the emission cheats, crime against consumers is nothing new for them. The EU has heavily fined them three times for price fixing, first €4 millions, then when repeated three years later, €31 millions, and in the latest case involving their Scania truck company, a massive €880 millions.

If you get a chance sometime, beg a Leaf test drive. You'll discover the normal gentle braking of regen on lifting off, and by flicking back the drive puck to B mode, you'll find how strongly that brakes. It's too strong for holding the car at 30 mph on a 10% downhill, slowing it down, just balancing it at 30 on a 15% downhill.

Here's further proof that regen does the normal braking. On my new Leaf there's the choice of using e-pedal instead of normal two pedal driving. In that mode lifting off a little does the usual regen braking, lifting off further applies the brakes as well.

If that was similar to what it did usually as Audi claim, why would it now be provided as a choice?
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it names Nisan and Jaguar.. which suggest that the information given is true.
 

flecc

Member
Oct 25, 2006
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it names Nisan and Jaguar.. which suggest that the information given is true.
I saw the Jaguar mention but didn't see any mention of Nissan.

Still rubbish though, I've gone through all the claims and they are often false. They say pressing the brake pedal on all other cars operates the brakes, that only theirs uses regen for braking at first.

Not true. Mine when the brake pedal is gently applied just uses the motor regen braking force and displays the amount of regeneration on the Plus-Minus current consumption dial. As the pressure is increased the regenerated amount rises until the brakes are engaged too. Then it's clear the braking is on all four wheels, not just the front wheels by the motor.

It may be theirs is more efficient, I wouldn't know. But I do know how mine works.
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mike killay

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Feb 17, 2011
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I saw the Jaguar mention but didn't see any mention of Nissan.

Still rubbish though, I've gone through all the claims and they are often false. They say pressing the brake pedal on all other cars operates the brakes, that only theirs uses regen for braking at first.

Not true. Mine when the brake pedal is gently applies just uses the motor regen braking force and displays the amount of regeneration on the Plus-Minus current consumption dial. As the pressure is increased the regenerated amount rises until the brakes are engaged too. Then it's clear the braking is on all four wheels, not just the front wheels by the motor.

It may be theirs is more efficient, I wouldn't know. But I do know how mine works.
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I wonder what it will be like on ice?
Or is there a lever for that as well?
 

flecc

Member
Oct 25, 2006
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I wonder what it will be like on ice?
Or is there a lever for that as well?
Not quite a lever.

Mine has the following gizmos:

ABS - Anti-lock Braking System.

ESP - Electronic Stability Program.

ICC - Intelligent Chassis Control.

Whether any of it is any use on ice is yet to be discovered.
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4bound

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The proof is that owners report the brake pads almost never need renewal, since with normal driving they are only used for emergency braking.
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Doesn't this mean a greater chance of needing new discs since the pads are not clearing the surface rust which seems to happen on discs? I've been told by my dealer that my rear discs need replacing because I haven't been braking hard enough!
 
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mike killay

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Feb 17, 2011
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Not quite a lever.

Mine has the following gizmos:

ABS - Anti-lock Braking System.

ESP - Electronic Stability Program.

ICC - Intelligent Chassis Control.

Whether any of it is any use on ice is yet to be discovered.
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I am baiting my breath.
Please keep us posted,
Mike
 
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flecc

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Doesn't this mean a greater chance of needing new discs since the pads are not clearing the surface rust which seems to happen on discs? I've been told by my dealer that my rear discs need replacing because I haven't been braking hard enough!
Unlikely in my experience. So long as the pads do some rubbing the discs stay clean. On the Leaf, even when driving mainly on motor braking, that's not precise so the brakes are still used to stop the car at the desired point so still get that regular light use.

I have seen enough disc rusting to ruin pads and create more disc wear on cars that have long outdoor parked up periods out of use. I never suffered it myself on garaged rarely used cars though. That includes a Fiat Tipo at a time when I almost only cycled and only got the car out of the garage four or five times in each of the last seven years of it's ten plus years with me. It was doing about 400 miles each year!
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Marc Draco

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Aug 5, 2018
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Not sure where we got with this but I just saw an eBike "hack" (I was too tired to see what the darn thing was called) but it was supposed to drive your back wheel VIA the rear tyre! It has regeneration too.

Nice idea but can you imagine the cost in tyres!?
 

flecc

Member
Oct 25, 2006
48,185
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Not sure where we got with this but I just saw an eBike "hack" (I was too tired to see what the darn thing was called) but it was supposed to drive your back wheel VIA the rear tyre! It has regeneration too.

Nice idea but can you imagine the cost in tyres!?
There have been many friction drive bike motors with ridged or abrasive rollers rubbing on the tyre treads.

One of the earliest was the American Zap motor kit, but there were many others and there's at least one being crowd funded at present.

Sinclair got involved too with three tries, two of them under the Zeta model name, one for front wheel, and one for rear wheel.
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Marc Draco

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Aug 5, 2018
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I saw the dratted thing on YouTube again last night (I was in bed and not supposed to be on the computer) so I've forgotten what it's called.

Is it just me or do these things seem attractive in theory but in practise the cost in tyre wear (and the maintenance of changing them) defeat the object? It's not like having a little bottle dynamo (I kinda miss those) for your lights.

This latest iteration seems rather like the Zeta you've linked here Flecc (and thank you for that).
 

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