Implementing regenerative braking on electric longboard

Lightweight / Folding / Portable EVs - seats optional
User avatar
beto_pty   1 kW

1 kW
Posts: 480
Joined: Dec 17 2013 8:20am
Location: Panama City, Republic of Panama

Re: Implementing regenerative braking on electric longboard

Post by beto_pty » Jun 18 2014 10:20am

Guys Guys guys...
We are ignoring the basic point... Regen (be it 80% efficent or 3% efficient) only works when braking, which by the way is ignoring the fact that only 12% of the energy comming from the batteries would translate in to motion on a car, the rest is heat and friction, wheel deformation, wind resistance, shock absorbers, that fancy radio with 1000 amp speakers, ac power windows, lights, blinkers, rellays, heated seats and such.

But for arguments sake lets say you get in your 80% regen tesla, start your car get on the highway which conveniently does not require you to brake, ride the highway for 2 hours in a manner where you do not brake once (would like to live in this fictional world) , get off the highway and conveniently coast to a stop at your destination without having to brake... Well your total regen was 80% of Zero... I understand my oversimplified example is imposible, but it illustrates the fact that if we brake 21 times for aprox 5 seconds each time in the course of a 1/2 hour drive from 40 mph to zero, we will be regening (acording to testla..not me) 80% of this.. allowing us to drive 80% of 105 seconds x 12% translational efficiency applied at 40 mph.. for an awesome extra 10 seconds...at the previous charging power of 40 mph.. and extra 0 .1 mile. (the example is based on me counting my braking from my home to work today)

Of course this might be different in a bumper to bumper example or when a large portion of the drive is downhill. Regen unless someone can prove me otherwise continues to be a marketing scheeme.. and a very cool sales argument...IT exists, i dont deny that... it is however not significant to 90% of the potential flatarea/non bumper to bumper users
Do or Do not. There is no try
PATY/neta http://endless-sphere.com/forums/viewto ... 35&t=65384
MIni-motor Build http://endless-sphere.com/forums/viewto ... 35&t=56839
Destroyer http://endless-sphere.com/forums/viewto ... 35&t=58504
Adrianas Board http://endless-sphere.com/forums/viewto ... 35&t=61171
Gargoyle http://endless-sphere.com/forums/viewto ... 35&t=61569
Velociraptor: 6s 10.4ah, Ezrun150, 9.8 mm abec11s, Quanum, 5060NTM, 16/48 hdt5, Piggyback Charge

Hummina Shadeeba   10 MW

10 MW
Posts: 2004
Joined: Apr 25 2014 10:26pm

Re: Implementing regenerative braking on electric longboard

Post by Hummina Shadeeba » Jun 18 2014 11:47am

[quote="beto_pty"]Guys Guys guys...
We are ignoring the basic point... Regen (be it 80% efficent or 3% efficient) only works when braking, which by the way is ignoring the fact that only 12% of the energy comming from the batteries would translate in to motion on a car, the rest is heat and friction, wheel deformation, wind resistance, shock absorbers, that fancy radio with 1000 amp speakers, ac power windows, lights, blinkers, rellays, heated seats and such.

But for arguments sake lets say you get in your 80% regen tesla, start your car get on the highway which conveniently does not require you to brake, ride the highway for 2 hours in a manner where you do not brake once (would like to live in this fictional world) , get off the highway and conveniently coast to a stop at your destination without having to brake... Well your total regen was 80% of Zero... I understand my oversimplified example is imposible, but it illustrates the fact that if we brake 21 times for aprox 5 seconds each time in the course of a 1/2 hour drive from 40 mph to zero, we will be regening (acording to testla..not me) 80% of this.. allowing us to drive 80% of 105 seconds x 12% translational efficiency applied at 40 mph.. for an awesome extra 10 seconds...at the previous charging power of 40 mph.. and extra 0 .1 mile. (the example is based on me counting my braking from my home to work today)

Tour view on it makes sense to me. Regen is over-rated maybe depending on what type if driving/braking your doing. But at first you were saying the tesla only gets 12% efficiency from battery to road. I'd read it was 80%. So 80 from battery to road, then 80 from road back to battery when braking, giving 64% efficiency in a strange world where you'd get to speed, not coast, then brake back down to 0. Or maybe that's what most driving is like these days in the city.

tallakt   1 µW

1 µW
Posts: 1
Joined: Sep 22 2016 3:09am

Re: Implementing regenerative braking on electric longboard

Post by tallakt » Sep 23 2016 3:39am

I believe an argument for regenerative braking is that the battery can really efficiently absorb energy. Otherwise, that breaking energy would have to be dissipated in the motors, ESC or resistors. Using regen braking will lower the component cost...

As a starting point to see how much energy that could be retrieved,. To calculate the amount of absorbed energy use: motor effiency at that RPM x efficiency of regenerative braking ESC x efficiency of charging... I would assume the number would end up around 50% for something that was not built by NASA...

Post Reply