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is a Regenerative Braking necessary for electric bicycle?

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Joined: 04/06/2011
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Points: 34

Hi budy,

Recently, many customers ask if our electric bike conversion kits inlcude regen braking. I do not understand why they all want to this feature on their ebikes. The regen braking will not necessory for a electri bike. It is original for electric cars, not much energy can be saved to battery when the e bicycle in actual using. That is just a selling slogan and waste money.

I want to find some support of my opinion and at least I found one. I think this link will more convincing: http://www.ecospeed.com/regenbraking.pdf

If some guy has the some idea, please share your idea.Thanks.

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Joined: 03/19/2012
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Re: is a Regenerative Braking necessary for electric bicycle?

I do not think it is useful either.Some providers are cheating.

MEroller's picture
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Joined: 09/26/2011
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Re: is a Regenerative Braking necessary for electric bicycle?

I guess it all depends on the usage of an e-bike. On long downhill runs regen will surely be beneficial in an e-bike too! But on your regular level road rounds it will be all but unnoticable range-wise.

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My ride: E-Sprit Fury (basis is the ZAP/Erider Thunder 5000) since May 03, 2011. Mods: Battery temp. gauge and battery heating (off the grid and off the battery), Kelly KEB72801X, reverse activated, luggage rack with topcase, HC Cycle Analyst, Emsiso BMS2405, 35mm³ battery cables

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Joined: 02/24/2007
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Re: is a Regenerative Braking necessary for electric bicycle?

Regen breakes are future of every good ebike. Tidal Force has it, E+ has it, Optibike has it. And all three are one of the best you must agree.
You forgot that they are there to save brake pads on disc breakes pads are rather expensive.
Also rims will last much longer
Grinding metal and rubber ???
I cannot imagine ride without them.

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CM

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Joined: 07/09/2011
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Re: is a Regenerative Braking necessary for electric bicycle?

I have three scooters, one with strong regen controlled by the throttle (Oxygen lepton), one with no regen (XM-3000) and one with regen supposedly activated by braking and deceleration (ZEV 5000).

The Lepton: the regen is generally a good feature, but it also prevents you from coasting - you have to keep the throttle open and the motor running except on steep downhills. If it were activated by the brake levers only, the combination of coasting and regen would probably extend the range by 10% over what it is. Interestingly, the Economy mode, with its proportionately weaker regen, seems to add more range. I think it may be two things: the regeneration 'events' last longer and allow for greater charging efficiency as opposed to the very strong Sprint mode regen that slows the scooter *very* quickly, and Eco mode uses less power, so the range estimator goes up more for that reason. Another quirk: going down a steep hill in Sprint and using regen, the range estimator will usually *subtract* range at the end. I don't know why.

The X-Treme XM-3000: regen would probably help if activated by the brakes only, but when the manufacturer claimed that coasting adds a lot of range, they aren't kidding. Those five heavy GreenSaver batteries make the scooter want to keep rolling for much farther (and *much* faster on downhills) than you'd think. I think that its lack of regen isn't a big minus at all.

ZEV 5000LA: the first reviews of this scooter that I read mention very strong regen on braking. Mine seems to have very little, or even none at all. This may be due to a change in controller programming, crash damage, or just a quirk of this model. Anyway, the same strong coasting ability helps as with the XM, but strong regen on brake activation would be very welcome, both to extend range and to help the adequate but unimpressive disk brakes.

As for bicycles, I think that brake-activated regen would be nice, but don't know that it would add much range. The only eBike I owned (a defective Giant LA Free Sport) didn't have it. The best argument would probably be price: if regen adds 10% to the price and only 3% to the range, it isn't really worth it for most people...

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Joined: 06/22/2009
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Re: is a Regenerative Braking necessary for electric bicycle?

My XM-4000li does not have regen, but my XM-700li does. It would be my opinion that regen added very little to the range of the 700li and the 4000li is fine without it for the reasons the author mentioned. It takes 3 hours to fully charge the batteries on both cycles. Over the course of a ride, is 5 minutes of regen braking going to be significant??? It would be different if you could fast charge or "slam" energy back into the battery pack, but that reduces life.

If it is true that at 25 mph 80% of the energy is used to overcome wind resistance, then it might be wise to invest in a larger windshield. I certainly need one, as I am far above the current windshield on my 4000li and can envision cutting down on that wind resistance significantly. Has anyone seen an aftermarket windshield for the XM series or the ZEV's? My XM has the same body as the ZEV 5000LA mentioned above.

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Re: is a Regenerative Braking necessary for electric bicycle?

Having a Cycle Analyst on my scoot now I can confirm on average a 5% regeneration rate in my mixed country road and some city driving. That would mean 5% more range :-) And my regen only recuperates some 30A at sufficient speeds, so it still requires careful timing to use ONLY regen for regular stopping. I have found it to be most beneficial to apply my brake switch activated fixed regen right from cruising speed (as opposed to letting the scooter coast) and letting go of the brakes when speed has dropped below 20km/h, when regen current is reduced to a mere trickle. But due to very low aerodynmaic drag at low speeds I can still coast a considerable bit.
Letting the bike coast from cruise speed results in fast energy dissipation due to high aerodynamic drag, so less can be recuperated later on. I have a notion my method yields more range gain then coasting as much as possible during decceleration. I'll have to figure out a way to compare that...

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My ride: E-Sprit Fury (basis is the ZAP/Erider Thunder 5000) since May 03, 2011. Mods: Battery temp. gauge and battery heating (off the grid and off the battery), Kelly KEB72801X, reverse activated, luggage rack with topcase, HC Cycle Analyst, Emsiso BMS2405, 35mm³ battery cables

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Joined: 05/18/2012
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Re: is a Regenerative Braking necessary for electric bicycle?

I just like to add that the XB-700li does not have regenerating braking. It does not coast very well, but I think that has to do with the cheaper manufacturing, and some kind of leakage could be possible on the motor, when it generates the power from coasting.
Truth is, it does not generate in the batteries.

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Joined: 12/01/2006
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Re: is a Regenerative Braking necessary for electric bicycle?

Until I released its magic smoke, I had a DrainBrain (nee Cycle Analyst) attached to my XB600. It revealed that the XB DID have regen. It cut in above 23 MPH, and, on steep hills, put out up to 400 Watts. Its greatest function was as a speed governor; there was never any significant range extension.

The concept of utilizing kinetic energy to get "free" electricity is tantalizing, but the more mundane concept of utilizing kinetic energy to get somewhere by coasting is more directly useful.

Mark

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