Would you be interested in Energy Harvesting on your E-Bike?

Stihldog

Handheld Power Tool
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Jun 10, 2020
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Coquitlam, BC
How about we think through this with some common sense.

who would most use this?
Not performance bikers
Maybe commuters

you take a pole of how bumpy peoples commute is.
Here I’ll jump ahead and let you know that on most of our get-to-work-quick trails we choose fast and smooth so now commuters are out of the picture

so your hopes here are not worthless but pretty much not worth it....at all.
You may be right. My shock is probably not a big as your shock. I’m gonna stick to breaking eggs. ?
 

Zimmerframe

MUPPET
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Jun 12, 2019
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Brittany, France
You'd need to go one step up on what he basic physics are giving you.

Think heat exchangers.

Think Dyson fan thingy (actually a Toshiba invention from the 80's) Air based, but could you apply this to fluids to get say 15* more out of what's there ?

Ultimately, the amount of base energy recoverable is so small, it literally isn't worth it. You'd get more from a thermoelectric generator stuffed in the saddle.
 

R120

Moderator
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Apr 13, 2018
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At the moment with the available tech is a solution looking for a problem.

One of the problems for me in the industry is that with a lot of the new bikes EMTB's brands seem to be determined to add more and more crap to them, from electronic suspension, built in telemetry, ABS, bluetooth speakers probably too!

What we should be looking at is simplifying and streamlining.

There will come a time when it may be viable, but perhaps a better angle would be to see what could a dynamo hub do? Is their a possibility, most likely within the commuter market, for some sort of dynamo systems to recharge on the go?
 

Rob Rides EMTB

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Jan 14, 2018
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Surrey, UK
At the moment with the available tech is a solution looking for a problem.

One of the problems for me in the industry is that with a lot of the new bikes EMTB's brands seem to be determined to add more and more crap to them, from electronic suspension, built in telemetry, ABS, bluetooth speakers probably too!

What we should be looking at is simplifying and streamlining.

There will come a time when it may be viable, but perhaps a better angle would be to see what could a dynamo hub do? Is their a possibility, most likely within the commuter market, for some sort of dynamo systems to recharge on the go?

Come on now, I've seen your E-Sommet in the leafy Surrey suburbs...

IMG_4099.jpeg
 

paul-g

Active member
Dec 27, 2019
582
457
yorkshire
HYDROGEN
Hydrogen is a clean fuel that, when consumed in a fuel cell, produces only water. Hydrogen can be produced from a variety of domestic resources, such as natural gas, nuclear power, biomass, and renewable power like solar and wind. These qualities make it an attractive fuel option for transportation and electricity generation applications.
Several companies in the past have showcased their plans to use hydrogen fuel cell technology to power a bicycle. Recently, Chinese company Pearl Hydrogen became the latest company to showcase the idea, at a recent technology convention in Shanghaimart. The 20″ wheel prototype weighs 32kg and is powered by a PEM fuel cell and brushless electric motor.
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this is the only problem i can see
 

apac

E*POWAH Elite World Champion
Aug 14, 2019
1,326
1,172
S.Wales
Believe me when I say, I have had very very very strong active regen braking on a 50kg E dirt bike that produced 40amps of energy on initial grab of regen (all recorded) which would then taper off as the bike slowed. The rear wheel would actively try and reverse. I needed very strong custom made steel torque arm bolts so the wheel would not tear/twist away from the horizontal dropout. The return in energy was feck all. Over a two hour ride, using over 28ah of battery it would return about 1ah into the pack.
As said earlier by Rob, the gains in energy, weight, efficiency are in development of the chemistry of the cells, and not in regen.

However, regen does not add any weight to a system, but is usually only attainable with direct drive hub motor, and not geared motors, so you are unlikely to see them in middrive emtb's.
 

Zimmerframe

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Jun 12, 2019
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OK, so thinking about this over a beer, you can't just use either hydraulics or air as they are as you won't get enough from it in terms of WH. So you'd have to use the coanda effect or something to try and get more out of what you have to induce fluid induction. If you managed to invent something to do this at this scale, then I'm not sure if would fit in the fork/shock so would need a piggy back/or hydraulic/air hose to your coanda effect device. As this is all going to be tiny you'll need to get as much out of it as possible so you'll probably need to invoke some form of fluid entrainment to drag every WH you can out of it to overcome all your efficiency losses of making the system in the first place. Each bit you add, potentially removes the advantage of adding it as everything is so small, so friction losses and so on counteract anything you might gain.

Theoretically, you might get a 7-10* gain .. But then where do you put things and would you get those gains real world on such a small scale ? You'd also need clever valving so you gain on up and down strokes.

Not easy !
 

steve_sordy

Wedding Crasher
Nov 5, 2018
8,361
8,587
Lincolnshire, UK
It will probably be more energy efficient to reduce the weight of bike and rider!
I used to be able to do that calculation.

Edit: In fact unless the gizmos are light, there would be as much energy consumed in moving them about (along and up and down) as it would generate.
 

Gary

Old Tartan Bollocks
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Mar 29, 2018
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We are talking about power harvested from the suspension damper here, not brakes... All those bumps and shocks its absorbing as you go.
Clearly miles of range from the brakes would require them to be permanently on hahaha
How much knowledge of mtb suspension fork and shock design and function do you presently have?
Would you agree that in order for shock and fork dampers to be used to give back a worthwhile amount of storable energy they'd need completely re-designed.
MTB suspension is fairly decent at present but there's always room for improvement but not so much for a reduce in performance
 

Gary

Old Tartan Bollocks
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I should add .... so as not to lead @MunnsyBiker excitedly down a rabbit hole ..

If you are a student ... you have probably never ridden a bicycle with an old school dynamo powered light ..

Try and find one .. and ride it ..

It's quite impressive how much harder it is to ride to power this tiny tiny little generator which creates about as much light as a wasp lighting it's own fart during a party.
Have you ridden a modern one? :cool:

things have moved on a little ;)
 

Gary

Old Tartan Bollocks
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Indeed, but we are talking 5-10 Watts range on average, peaking higher and dropping lower of course depending on terrain.
Considering a phone charger uses 2-6 Watts... not negligible
and what percentage of that 5w could you realistically trickle charge back into the battery while the bike is ridden? Say 50%?
Remember shocks only heat up a lot on longer descents. most of the riding time is still spent on relatively smooth climbs. and plenty riders choose to lock their shock out.
Emtb rides are rarely any longer than 2hours actual riding time so all that tech and cost and hastle would be for a measly 5wh (1%) extra battery range?
You do realise many Emtb riders give away between 50-100w to a normal XC bike on climbs simply because they've choosen to run the most agressive, soft compound, heavy strong casing tyres... often with inserts and usually at pretty low pressures?
 

Gary

Old Tartan Bollocks
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Just seen this
Indeed so at 5 or 10 Watts, cycling for an hour, youve effectively then achieved 1-2% of your batter capacity.
Half for wastage gives 0.5-1% of the battery. Therfore in one hour youve potentially gained half a kilometer. over a longer ride who knows.
But yes its not going to be half your range again sort of energy...
Er... No you haven't
You've gained less than 160metres for a fully drained battery ride if we are talking actual hilly mountainbiking routes. (3-4000ft of elevation)
If you're lucky it might be the difference between one more trip to the trail centre coffee shop from the car park

Do you actually ride mtb?
 
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