Regenerative braking

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vanman
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Regenerative braking

Postby vanman » Sat Jan 11, 2020 9:17 pm

Today I was following a learner driver in a Toyota Auris hybrid car, I was keeping quite a distance back but noticed where I would expect the brakes to be applied nothing. Ok fine the car was using regenerative braking.
My querie here is this strictly systematic? brake lights being one of the key information givers, warning all following traffic of potential hazards.
Perhaps these vehicles should show brake lights when the regenerative system is in operation as well as when braking normally.
Yeh I know no chance just an idea.

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jont-
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Re: Regenerative braking

Postby jont- » Sat Jan 11, 2020 9:42 pm

vanman wrote:Today I was following a learner driver in a Toyota Auris hybrid car, I was keeping quite a distance back but noticed where I would expect the brakes to be applied nothing. Ok fine the car was using regenerative braking.
My querie here is this strictly systematic? brake lights being one of the key information givers, warning all following traffic of potential hazards.
Perhaps these vehicles should show brake lights when the regenerative system is in operation as well as when braking normally.
Yeh I know no chance just an idea.

I think they do, although maybe it's manufacturer dependent or how much regen is going on?
https://insideevs.com/news/322708/bmw-i ... est-video/
(some cars can change the amount of regen from just lifting off the accelerator).

I have to be aware in the caterham too, since lifting off the gas has a similar effect (short gears, high compression, airbrake from the windscreen), and I'll sometimes just dab the pedal enough to show the lights.

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angus
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Re: Regenerative braking

Postby angus » Sun Jan 12, 2020 11:26 am

A while back I was following a Tesla and I was surprised how often the brake lights came on (almost every bend) and concluded that just lifting off lit the brake lights.

2 thoughts regarding the learner tho': aren't all hybrids automatics? And considering how little leeway some drivers give learners, how long before the toyota gets shunted without the brakes lights warning the prat behind?

vanman
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Re: Regenerative braking

Postby vanman » Sun Jan 12, 2020 2:12 pm

how long before the toyota gets shunted without the brakes lights warning the prat behind?[/quote]

Good point, not long. hope they keep off the M23 at present 50 speed limit with nearly all one car length apart. :evil:

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Horse
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Re: Regenerative braking

Postby Horse » Sun Jan 12, 2020 4:14 pm

jont- wrote: I have to be aware in the caterham too, since lifting off the gas has a similar effect (short gears, high compression, airbrake from the windscreen), and I'll sometimes just dab the pedal enough to show the lights.


Worth knowing that motorcycles respond in a similar, so can slow substantially without showing a brake light. Some bikes more than others, typically big twins and singles.
Your 'standard' is how you drive alone, not how you drive during a test.

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GTR1400MAN
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Re: Regenerative braking

Postby GTR1400MAN » Mon Jan 13, 2020 9:03 am

Yes, I was going to mention the Bavarian tractors where closing the throttle throws an anchor out the back! :)

It's something we warn all new observers about (you will get surprised one day) and discuss with associates about considering the need to show a brake light with a little pedal pressure.
Mike Roberts - Now riding a Triumph Explorer XRT. My username comes from my 50K miles on a Kawasaki 1400GTR, after many years on Hondas of various shapes and styles. - https://tinyurl.com/mikerobertsonyoutube

Gareth
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Re: Regenerative braking

Postby Gareth » Mon Jan 13, 2020 9:50 am

GTR1400MAN wrote:about considering the need to show a brake light with a little pedal pressure.

How much pressure? Is it always 'almost no pressure', or is it possible to apply a little braking without the brake lights illuminating?

Similarly, on some vehicles is it possible to illuminate the brake lights with no slowing? Would be handy for brake testing ...
there is only the road, nothing but the road ...

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Horse
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Re: Regenerative braking

Postby Horse » Mon Jan 13, 2020 1:28 pm

Gareth wrote:
GTR1400MAN wrote:about considering the need to show a brake light with a little pedal pressure.

How much pressure? Is it always 'almost no pressure', or is it possible to apply a little braking without the brake lights illuminating?

Similarly, on some vehicles is it possible to illuminate the brake lights with no slowing? Would be handy for brake testing ...


On bikes, the rear brake light switch usually operates before any useful braking occurs.

Worth noting, for non-riders, that bikes usually have a very powerful set of front brakes (lever on the right side handlebar) and a weedier one on the rear (operated by a foot pedal). Use of each depends on what you're doin at the time* and how much slowing you want to achieve.

* One example is slow (walking speed) where usually** the rider would use the rear brake to aid control ******

** Some bikes have linked brakes, so even if one is applied, the system will apply the other *** ****

*** Moto Guzzis don't work like this, they have two independent systems, where the front lever operates one front disc and the foot lever operates the other front disc and the rear discs(well, my Guzzi did)

**** From encouraging a trainee to experiment on his big Honda, using both brakes well achieved shorter stopping distances than letting the linked brakes do their magic *****

***** Just to add some complication to what would otherwise have been a simple explanation, for a while BMW sold bikes with servo-assistance

****** You can use the front brakes during slow speed riding, but (particularly when leaning over) if done without a great deal of finesse is likely to prove a costly experience
Your 'standard' is how you drive alone, not how you drive during a test.

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GTR1400MAN
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Re: Regenerative braking

Postby GTR1400MAN » Mon Jan 13, 2020 4:31 pm

Horse has covered most while I've been out playing on a test bike :)

The rear brake light switch on most bikes is user adjustable.

Linked brakes - there are several methods per manufacturer's patent. Some are speed dependent allowing just rear at slow speed. Some can be felt in action. Most are not noticeable.

Linked brakes 2 - A can of worms and riders fall in two camps. Love/hate. Explain that GP bikes have linked brakes and semi-auto DCT gearboxes and they stick their fingers in their ears and go La La La. Show them a quick-shifter and they'll drool. Strange folks some of these bikers :)
Mike Roberts - Now riding a Triumph Explorer XRT. My username comes from my 50K miles on a Kawasaki 1400GTR, after many years on Hondas of various shapes and styles. - https://tinyurl.com/mikerobertsonyoutube

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Mr Cholmondeley-Warner
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Re: Regenerative braking

Postby Mr Cholmondeley-Warner » Tue Jan 28, 2020 7:55 pm

Teslas show the brake lights when the software thinks it necessary (and show them on the avatar on the dash too). The regenerative braking is very strong - would bring the car to a halt on a moderate downhill slope almost as quickly as smooth use of hydraulic brakes. Pretty much one-pedal driving.
Nick


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