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As the Ebike becomes more entwined with peoples outdoor activities, there is that problem of recharging, when there is no power source to recharge from.
Example would be away bike packing. Once the power drops, you need to find some premises or other with charging facilities.
So I took a look at what is available in folding wind turbines, the type or which has been long available for yachts.
Not sure at this stage of development how much power can be drawn to recharge, but its usually windy, and maybe having something with you as an emergency back up might be a handy thing indeed.
The ones on boats never really supplied a great amount of charge, but the tech advanced today in wind power generation has come a very long way.
Something you could plug in and just leave it overnight.
Perfect for Scotland, it's always bloody windy up north.
I've also seen mini water turbines you place in a stream/river which will also produce free power.
We are a long way off anything you can fold up and carry that will make a dent in an ebike battery
Typical folding wind turbines designed for portability in anything other than a vehicle are in the 5v 2-4amp range......
And your trying to charge a 40+v 400ah battery.
What he said, really. To charge your phone, great, to charge a bike, not so much.
what about some kind of pedal powered dynamo?
(ducks and runs away!)
to clarify I don't have a problem with e-bikes, I just wanted to give a viz top tips style answer
Trailer with a small petrol generator?
Diesel Electric pushies the next big thing.
Even charging it up from a reasonable sized large van based solar array.....about 50 X the size of what your going to carry on the trail is as yet not going to make much of a dent.
Personal trasportable devices would give enough to trigger the BMS.
And your trying to charge a 40+v 400ah battery.
Not that big - they're around 400 Wh not 400 Ah. So if your turbine really can generate 20 W then it could half charge the bike overnight.
Not that big – they’re around 400 Wh not 400 Ah. So if your turbine really can generate 20 W then it could half charge the bike overnight.
To do 20W you'd need a 1.4m diameter turbine and a consistent windspeed of 20 mph
(I've assumed turbine is 50% efficient in converting kinetic energy of wind to electric which I believe is still ambitious - 100% is stopping air dead)
Mat above has it.
Wind turbine output is related to the square of the blade size. So half size = quarter output, quarter size = 16th output etc.
Having had two 'proper' 2m bladed turbines on a Scottish hillside for a few years at work, I can confirm that the £20k install and £650 per anumn service cost boiled the kettle, not much more.
Can you arrange it to assist with cycling into a headwind?
😜
World has gone crazy. Just take a bike and pedal it. Recharge by eating food then carry on pedalling it.
The real question is are there actually any "E-bikepackers" though?
Bike packing with a motor and battery sort of seems to contradict the whole being self sufficient and getting away from the rat race type ethos... or is it just me?
How about a front generator hub with plastic blades that can be clipped onto the spokes? You park your bike with the front wheel off the ground and it'll work as a wind generator to charge phone batteries. When you're riding, it could be activated by the rear brake lever, so lightly dragging a brake on descents will activate regenerative braking.
The real question is are there actually any “E-bikepackers” though?
The niche is already filling up well.
https://ebiketips.road.cc/content/news/kona-unveil-new-remote-e-bikepacking-plaftorm-660
franksinatra
Full Member
World has gone crazy. Just take a bike and pedal it. Recharge by eating food then carry on pedalling it.
This ^
Just carry a spare battery surely? You've got power assist to help you get it up the hills. Just stay off the turbo boost mode and you've doubled your range.
Or if you want to carry a concentrated power supply for longer range with you get a motorbike.
Effectiveness of wind energy generation is also very dependent on the quality/consistency of the wind, which is why utility scale turbines are so tall. This is one of the principal reasons we don't see very much small scale wind generation despite full scale onshore wind being our cheapest form of newly installed generation for quite a few years now. Over the same time period PV has come down per unit generated a long way, and at the same time is just as doable on a domestic or even portable scale.
Even turbines with tip heights of 100m are quite limited in their performance compared with machines of 2+MW, illustrating just how high up you have to be to get away from the effects on the wind of topography, trees, buildings etc. TO operate to their potential, blades have to be up a lot higher than any object upwind because effects of drag go quite a long way beyond the size of that obstacle.
Edit: and re wanting to carry round a generating device to charge your e-bike battery, that foes seem crazy!
The real question is are there actually any “E-bikepackers” though?
its something I have considered but the range of ebikes makes it impractical
I'm not sure why I'm posting here since I know nothing about wind turbines and I don't for a moment think this idea is practical - but...
To do 20W you’d need a 1.4m diameter turbine and a consistent windspeed of 20 mph
...seems a little low. According to https://rechneronline.de/wind-power/ a 0.7m radius turbine in 9 m/s wind with 40% efficiency can generate 270 watts.
How about a front generator hub with plastic blades that can be clipped onto the spokes? You park your bike with the front wheel off the ground and it’ll work as a wind generator to charge phone batteries. When you’re riding, it could be activated by the rear brake lever, so lightly dragging a brake on descents will activate regenerative braking.
Or just use the perfectly good extant solution of a dynamo hub?
During daylight hours when lighting isn't required, you just charge a powerbank to top up GPS/phone/torch/toys? and/or simply carry a pre-charged powerbank?
I'm not totally sure anyone would want to be erecting a temporary windfarm after a day of pedalling, not when your major concerns are likely to be food/shelter/sleep in that order.
I like a gadget as much as the next muppet but TBH if it's more effort than something as passive as a dynamo, I'd not be interested...
…seems a little low. According to https://rechneronline.de/wind-power/ a 0.7m radius turbine in 9 m/s wind with 40% efficiency can generate 270 watts.
oops yep I went the wrong way with my mph to kph conversion! Fair enough, would need to be 0.35m.
Can you arrange it to assist with cycling into a headwind?
Of course!
https://www.wired.com/2012/07/wind-powered-car-upwind/
(I like the pedal powered generator idea most though 😀 )
Solar!
Back in summer I rode three days through the Bavarian Alps on my eBullitt loaded with water, camping gear and wine. 260km,1200 metres of climbing on one charge.
Use your legs until they're burning and then resort to the battery.
What if you took a treadmill generator with you, you could ride your bike on the treadmill at night, charging up the bike?
You would just have to be careful not to take off.
So do e bikes not have a regen mode you can use to harvest energy on a downhill?
The niche is already filling up well.
https://ebiketips.road.cc/content/news/kona-unveil-new-remote-e-bikepacking-plaftorm-660
Just looked at the 2021 Kona Remote and looks like that niche is dead in the water already.
Wind turbine output is related to the square of the blade size. So half size = quarter output, quarter size = 16th output etc
Yup.And the cube of wind speed,which is why location is so important.
So, if solar panels are getting more efficient, why not make the blades of the small, portable wind turbine out of PV cells? The. You have both sides of the thing covered!
So do e bikes not have a regen mode you can use to harvest energy on a downhill?
with a hub motor its relatively straightforward to do so but only gains you a little. with a BB mount motor its almost impossible to do due to the freewheel needed between rear wheel and the motor. I think it could be done if you used a hub gear with no freewheel and used an electro magnetic clutch in the motor but no one has tried it. Basically its almost impossible to use the bike to drive the motor as a generator
What if you took a treadmill generator with you, you could ride your bike on the treadmill at night, charging up the bike?
put the treadmill on a slope and you can just freewheel down it, no need to pedal
Sorry for DM link.... but no reputable newspaper would have reported this nonsense
https://www.****/news/article-2132223/Chinese-farmer-builds-wind-powered-car-reach-nearly-90mph.html
THE WIND POWER EQUATION The wind power equation is expressed as follows:
P = 0.5*ρ*A*V³*E
Where: P = Power in Watts ρ= Air Density in Kg/m³ (about 1.225Kg/m³ at sea level, less higher up) A = Rotor Swept Area in m² = πr² (r= radius or blade length) V = Wind Speed in m/s (cubed) E = Efficiency in percent
Matt OAB had me confused. Cube of the swept area is the biggie here. The bigger the blades, the better.
I was involved in testing portable renewable energy sources a few years ago. Portable wind just isn't worth it, portable pico hydro too heavy and too difficult to use for most, portable solar not much use if moving. Bigger batteries are still more efficient than generating.