Great idea. What about efficiency vs drag when compared to a dynamo hub? I am going to try it on my randonneuring bike. :). If it really works, I would prefer this over hub dynamo. Why I never taught about this? :) I wish had a little more creative mind like this. This is why I love this channel.
@@travelersimports6915 I'm pretty confident the drag is superior here but the real issue is the efficiency of the system. The frontal area looks to be bigger and the fan shape isn't designed for this job but to move air around so it's using drag (instead of lift, like wind turbine) in order to move. It's also less efficient because the theoretical max energy you can extract from wind it's 59.3%, lifting wind turbine achieve just under 40% tops and drag turbine are usually around 20%-25%. We can calculate the maximum power available to the fan at certain wind speed by calculate the swapt area of the fan. Looking at the fan mounted to the bike I assume it's diameter to be about 20 cm. At 20 km/h you have 3.3 watts of wind power, if the fan efficiency is 25% the output is 0.825 watt (5V and 0.165A). At 30 km/h wind power rise to 11.2 watts, at 25% fan efficiency it's 2.784 watt (5V and 0.56A). To achieve a bit more than 1A at 5V required for charging the shifters you need to reach about 37 km/h of wind speed. If you have tailwind you are screwed 😂 An hub dynamo it's only dependent on wheel RPMs so only the generator efficiency and conversion (hubs usually generate AC instead of DC like the fan here) matters and tailwind actually help here! Not as comparison because of a different stabilizer (and could be really make a difference), just as a single data point, with my SON dynamo hub paired with the Forumslader Pro stabilizer I reach 5 watts of power output (5V 1A) at about 20 km/h, also if I disconnect it for save some of my own energy (long climbs) the drag of the generator is just 0.5 watt.
you need a full bridge rectifier circuit on that one. because a generator produce AC voltage. A bridge rectifier turns it into DC to be use for electronics.
There's nothing wrong with hub dynamos I still use them on my bikes to power the automatic shifting and backup lights. They generate some actual useful power like up to 5W. Still an interesting idea and fun experiment that little wind turbine.
I have entertained the idea of a dynamo hub for a few years but ended up with a bottle-turned-into-Li-Ion-accus-container (now 4x16850 - but eight should fit too) - because I use different wheelsets during a year.
@@MikeMassey-fi5of Good hub dynamos have around 2W parasitic drag (source: cyclingabout). The thing that might not be complitely intuative, is that the "wind turbine" also generates drag (power out + loses). If we are talking about drag on bike using batteries vs bike using dynamo hub, that is different story for a different aplication. Drag of the hub dynamo is still significanlty less than the effect on roling resistance of the slight differences between road surfaces or tire brand and model, and even the variation in tire presure between two tires or the difference between optimal pressures vs road surface type.
Why on earth was a brushless outrunner motor shown while explaining a brushed dc motor...different animals entirely. Might need to send an electrical engineer by to check your tickets! J/k keep up the fun video content!
Definitely. Why make a wind turbine when you could just convert rotational mechanical movement from the wheel to electricity. This turbine solution is probably more compatible across all types of bikes, but a dynamo is simply a better soluttiona in every other way.
Normal dynamos (hub or tire contact) are good enough, and there are complete charging-oriented setups available, including regulators. Mostly meant for bike travellers, but useful for a lot of other riders. And the tire contact ones can be folded away, so they don’t slow you down when not in use. Foldable solar panels plus a powerbank are also quite good if you go bike packing or travel.
A good hub dynamo is less than 1W of additional resistance when not connected. Which is probably less than the additional aero drag caused by the "non-draggy" contact dynamo.
@@gcntech only on multi day tours - and in the dark past when battery lights did not yet exist in a meaningful way 😉 (like, 30-40 years ago). Today, I ride with a small powerbank on one-night overnigthers, or through-the-night events like Vatternrundan and such, and hook up my lights when taking breaks (they don’t charge when in use). Mounting the dynamo is a bit of work, so I only do that for longer ones.
You could potentially increase the generating power by increasing the pitch of the blades, and housing the turbine fan in a 3D printed tunnel to guide more air past the blades. I'd like to see part 2 of this, where Aldo takes into account the potential for power loss due to aero drag
Since most of us already have little devices that use small batteries (phones, lights, etc.), maybe it would make more sense to create a dynamo that stores its energy in a slightly larger battery that could then recharge multiple devices at any time. So one could ride into a remote place and recharge a larger battery, which would then be able to recharge other things. Maybe that would be useful to bike-packing tours.
Go to the dark side and dynamo you will never go back. The watts used are irrelevant. The jump on and ride without anxieties of battery life is well worth it. I live wher it get crazy hot in the summers so riding in the dark is most days out. Being able to go out for hours without worry is great. Being able to run lights all day and night is great
One solution to something like gear shifting could be to use a generator to charge capacitors, they could build up enough charge to execute a few shifts very quickly without adding much resistance, maybe with a very small capacity low power battery that can take a trickle charge to power the "brains" of the system as that side of things likely only requires milliamps/volts.
"Dynamos aren't really used anymore" is rather radical phrasing. You can just get a hub dynamo and switch off the light during the day. No load, no added rolling resistance. I tried it. The wheel spins much more freely once I turn off my lights. Di2 can be charged via USB and devices that transform the hub dynamo's output into the same power you'd get from a USB port already exist. You could just charge your Di2 batteries as you go. It's not difficult to put together such a system, fully integrated. It could even sync with your head unit to automatically switch charging on and off for maximum battery health. And at sundown it could switch on a pair of lights for safety and compliance with traffic regulations. The only problem I see is that people won't accept an imperceptible loss in performance even if it means you practically can't run out of juice for your Di2 system or your lights. EDIT: The current to charge Di2 in its current state might be a little too low coming from a hub dynamo. There are ways around that though. If other batteries can be charged with the current (and they can, I tried it), then you can just use some of those in my hypothetical setup.
Would it be possible to have it only activated when you’re going downhill or only when you’re not pedaling (because then you probably just coasting or going downhill.)
I don’t brake enough to make it practical to carry the mech around the rest of the time to make regenerative braking worthwhile. But a switch on my front derailleur cable to engage generation only in high gear would save watts I need while climbing, and use them for electrical power storage while cruising and descending when I need them less.
@@ketle369 In short, yes. Modern head units can be paired with sensors that read your pedalling frequency and your speed. Plus their map data also contains info on elevation. The programming logic to set it up in such a way would also be really easy and certainly no burden for any modern device. The main hurdle is just that there is by far not enough demand for something like this. Practically nobody serious enough to buy a Di2 bike plus a head unit wants a dynamo "slowing them down". And it also looks different than standard hubs which is a cardinal sin in their view.
@@anwidocu I don't want to sound overly negative but there are a number of problems when trying to implement it that way. A hub dynamo is rated for like 3W. If it's only engaged while braking it might as well never be. For regenerative braking to work, you'll need a much beefier dynamo but they are actually going in the opposite direction. LEDs need less power so they went from 6W down to 3W which is obviously going to do nothing to slow you down. And if you decide to go with big beefy dynamos that properly slow you down and create meaningful amounts of energy to charge your devices, you'd need some kind of huge buffer battery to store that spike in energy to then slowly feed what you're charging. I'm unsure of the exact dimensions of such a system but it would certainly weigh several kilograms at least. BTW electric cars need traditional brakes because the regenerative ones aren't strong enough on their own in an emergency.
Difficult climb? Just flick a switch connecting your D battery to the propeller and relax with your hands behind your head as you're rocketed up the hill.
"Dynamos aren't really used any more." Maybe not by by boy racers, but doing a 1200k Audax on batteries is a royal pain in the butt. A small hub dynamo allows you to run your GPS with back-light and charge your phone as well as providing brilliant, care-free light fore & aft, and with a photocell in the headlight you don't even have to bother about switching it on. BTW, WW1 biplanes used gadgets like yours to drive airspeed indicators.
Some aeroplanes actually have this sort of generator that can be deployed in a total power failure. Just to keep the vital electronics going in a worst-case scenario.
Roadies will do almost anything to avoid using practical equipment. Dynamo hubs, steel, alloy, pannier bags and racks, handlebar bags, round seatposts, separate bars and stems, headset spacers, externally routed cables, mudguards. I’m half joking. But seriously, you could just buy wheels with dynamo hubs. They’re great and can be less of hassle than having to remember to recharge your lights. Great for commuting and cycling touring. It would actually be nice for GCN to do a video on dynamo lights or create more content that isn’t focused on expensive racing bikes.
It's pretty optimistic trying to get 1 amp from this motor. Modern batteries can actually hold pretty significant charge, and trying to charge them is harder then it looks. In you shows you often measure a power output on pedals. As I recall 200 Watts is about you usual power on tests. So leisure riding might be about 100 Watts? Shifter battery has about 500 mAh. So to charge it you need 5 Volts * 0.5 Amp = 2.5 Watts for 1 hour. If you using dynamo you can easily multiply it by 2 to account for energy lost on friction and voltage conversion in charger. If you use propeller, there is no magic: you would still lose same amount of energy in form of air drag, is fact you probably lose even more with propeller. So about 5 Watts for an hour? Don't even think about charging the phone with 5000 mAh, it would be 10 times more! So better just carry a spare battery or power bank and spend those watts on actual riding.
What You produce is less than You loose!!! Want to produce 20 w for charging you would have to put 30w in coming from your legs... which means that going up the hill you would be loosing your breath faster 🙂
I am surprised that electronic group sets are not self charging. It would be relatively easy to incorporate charging at the jockey wheels, and the power loss would be very minimal. Even 1W of charge would be far more than needed to maintain the battery.
I cannot believe you went to the trouble of researching and making the generator and not test it/prove it in the real world just because it was raining🤔 Any proper cyclist would have gone out in the rain to check it or at worst waited for a time when it had stopped raining.... Very disappointing, not sure I can take GCN seriously any longer🙄
Nice experiment the trick here is to just set up a power bank system, then have your riding group friends carry extra power banks that way you don't have to carry the weight just like some riders rely on other riders for tools and spares. Of course we all know a couple of riders whom talk and preach about carry tools and spares and then don't 🤣 Me personally if I needed a power source I would fit a dynamo hub if I needed that extra power while riding, but I don't use a head unit at all, if I need lights which is not very often I have nice bright ones for tha,t as for the phone I have a power bank for that and if Im doing my bicycle-train commute then I just being a cable and plug into the train's usb port, my new phone can go all day on a charge, Im not using it while I'm riding my bicycle, I like my alone time on the bicycle, that's why there is text, email, voice mail and DM if someone needs to tell me something or give some information. cheers PS next experiment should be attaching helium balloons to a bicycle to make its feel lighter although getting traction from the tires might be an issue. 🤣
use a 3.7v li-ion battery as an energy reservoir, charge it up through a BMS board by the windmill, use a boost converter to convert 3.7 v to a stable 5v for the shimano battery to draw current, this is how the config: Windmill -> BMS Input -> 3.7V Li-ion -> BMS Output -> Boost Converter -> 5V -> Shimano battery
the more number of 3.7v batteries running in parallel, the larger the energy reservoir is and the more stable the current than can feed to Shimano, however the heavier the setup to be carried on your bike
I used to use dynamos because I am very very old. They eat the sh&t out of the sidewall - and they *also* take a fair bit of extra power to do anything useful - back in the day it was incandescent bulbs, and so most of that energy went to heat, which was a really, really depressing way of making a pretty feeble light beam.
I tried the same thing with a computer cooling fan for a college project (and to save me buying a new disc brake dynamo wheel!) and had similar results. Everything worked on the bench, but out on the road it didn't seem to be a reliable enough power supply
Love this stuff! It's a fun, simple experiment. Keep diving deeper into this stuff and make an endurance beast bike... think bad lands endurance race or the ultimate apocalypse ( bikepacking) machine but keep it aero as possible.-you're not building a rock. -Solar panel disc wheels with tape cabling up the trailing edges and an internal inverter and hub on the cross bar. -Mount electric, waterproof, airfoil panier bags with pockets to hold stuff to be charged...and your clothes/tent dry. -You could even power an electric lunch box and route the radiant heat to heat up a small internally routed fluid filled tube to warm the bike frame and rider on cold days- think radiator on a car. Controlled by a thermostat on your headset. Nothing like heated saddle and warm feet on a long freezing bike ride. I'm not sure how to get that slashing through words off above. Where else can you recapture and convert wasted energy on your bike? What can you convert it to? By the way, it seems like you were trying to figure out your resistance drop when an electrical circuit is under a load. Start with Ohms law and figure it out from there. E=IR or R= E/I where E=volts, I=amps, and R=resistance.
You put a hyphen at each end of the strike throughed text. Google, "RUclips comment markdown" if you want a more thorough explanation. Think a space before the second hyphen (or a new line) would be what you're looking for. (I'll do an experiment below). No gap -Strikethrough- Space after word, before second hyphen -Strikethrough - "Enter" for new line after word. -Strikethrough -
A motor that small to use as a generator, at 5V, the ampage is quite small. It's quite possible that lights, a phone or head unit battery requires significantly less than 1 amp to begin to charge (albeit slowly).
law of conservation of energy - we don't create or make electricity we convert kinetic energy to electrical energy. Energy can neither be created or destroyed
Well, you can spot the non-bikepacker on the GCN team. "Dynamos aren't really used anymore." 😂❤ Alex, I would suggest using the fan generator to charge a powerbank battery - these are more tolerant of variable energy sources. And then using the powerbank to charge your phone/gears that are a lot more fussy about voltage and current.
Could work with a much larger battery without a regulator. At some point, the voltage of the battery would again stall the generator. Also needs a blocking diode to prevent the thing from becoming a fan.
Alex the problem with things not charging is likely because the generator won't be able to provide 1A. Most devices test the USB before starting to charge. They load it with more amps until the voltage drops too far below 5V. From that they know what current the charger is capable of. Some devices are OK taking a small current but some clearly have a minimum threshold. Its odd about the shifter battery as it will be small so should only require a small current unlike a phone battery. Maybe there is more to it and if USB C is involved there definitely is.
I certainly hope this will appear on Hack/Bodge of the Week! But I've got to say that I fall on the side of bodge. Hub dynamo is clearly the way to go here. Right from the beginning I was thinking "That's a pretty small fan. How much current are you going to be able to generate?" I also suspect it's quite an inefficient way of generating electricity given that you already have a rotating wheel. Still, it looks like a really fun project! It's the type of thing that would be awesome as a science fair project.
You could generate infinite volts from that fan if you could spin it infinitely fast, but you'll never get 1amp out of it unless you cut the resistance by half and leave the voltage unchanged, then you will double the amperage across the circuit. Probably still won't come close to 1amp though.
I find it so practical to carry a portable power bank with me on the long rides that I do not care much about adding anything to generate power on the go. There are solutions that even fit inside the handlebars and hold up juice pretty enough to power anything on your bike.
Cool, if silly, experiment. As many others said, I think you need to have a central power bank...that way your fan dynamo is trickle charging that, and you devices get an even charge. The other solution is to set up your bike like the boy from Kiki's Delivery Service....you clearly need a bigger fan!
The maximum power that can be extracted from the wind is defined by Betz's law P = 8/27 pv^3 A. Using a 10cm diameter fan at sea level, that means you'd need to go 32.4kph to generate the 2.5W you need to fully power a USB 2.0 device. And that's max theoretical efficiency! It only gets worse from there once you start to take stuff like the aerodynamic efficiency of your fan, the efficiency of your generator into account. If you want to make this work your first step would be to get a much bigger fan.
"Dynamos aren't really used anymore" - What world are you talking about? In this our world dynamos are totally being used, sometimes even on bikes with an electric motor, that already brings a big battery! And really, if I didn't chose very special tech, that is actually incompatible, I would have a SON dynamo on every bike, except the electric cargo bike. And I would use it for lights and USB with available hardware and it would be great. I am really often thinking about going back from my special stuff, just because I want the dynamo.
I love these little hacky projects from Alex. They're maybe not as ambitious as Blake's but I love that they're always exploring interesting ideas. More please!
That is not working at all.. You need the specification of that little motor? A real charger is able to put at least 5v 1amp. The amp is very important. Your little motor is rated for what?? 5v 0.2amps?? 12v 0.5amps?? What is the max RPM of that motor?? If the wind is get the motor RPM higher than the max RPM you will lost amps.
Well done! Appears you have a lot of people thinking of creating new or bringing back old technology. I had similar issues commuting in the cold weather when the temperature dropped below 0 C and my light batteries only lasted about 75 minutes. Solved it by purchasing a 5v 2A lithium battery weighing 1800 grams. Fits neatly inside my jacket to stay warm when ready for use. Warmer weather it fits neatly into my tool bag under the saddle. Cheers!
So if you are charging 5 V with > 1 amp you need … 5 VA of power, aka 5W. So at a bare minimum you need to be willing to push 5 extra watts for some amount of time to get your gear charger to give you another “zzzit”. Don’t know how many joules are needed per “zzzit”
Most electrical devices are not happy with constant changing power (voltage or current). From different riding speeds you get different power output. Most electrical devices will stop charging after a short time. You probably need a regulating device that charges something like a buffer battery. From this buffer battery you can get a constant output for devices like a smarphone. There are other workarounds and ideas from the people that use dynamo hubs. Dynamo hubs are still in use and popular with other forms of cyclists. You barely see them on road bikes, what GCN is all about. 🙂
Great idea! Perhaps invent a device that collect the wind speed aerodynamically in areas that make you ride faster, without increasing the price of the bike by 5-10K.🙂
Good idea. for touring and randoneuuring I use a Pedalcell generator, a more advanced (and efficient) version of the old dynamo. It's a great bit of kit. sadly the company has closed... lets hope they resurface soon. For most riding applications you just don't need it, especially with the good battery banks available these days.
Interesting proof of concept. Making usable voltage unloaded is one thing but being able to maintain it under load with the counter-emf applied is another. 5 volts at 1 amp is 5 watts. That's five watts of electricity out, not five watts of input. With conversion losses and other inefficiencies factored in (nothing is 100% efficient), this setup likely takes at least 10 watts of input on the turbine to function. Still, I could see something like this being used as an emergency power source.
Hi Alex, Have you tried gearing it up? Instead of direct drive to the shaft, use gear to spin the shaft faster? (Did I confuse you by using your actual name? LOL!)
This was a lot of fun, well done Alex. One use for this I could see is for those month or year long adventures rides into remote wilderness, however, a hub dynamo might work better. It was still a fun science experiment though. How long until you decide to head back into academia and start working towards that PhD?
"Dynamos aren't really used anymore and that is because battery tech has evolved a huge amount over the years" Um the majority of people I know in my city with a city bike have a dynamo for lights.
Nice science fair project! Probably could be made to work if the output could be pulsed! Same generator, way below its potential, but wouldn't stop the mill completely after a tiny current passes. Very low output.
I've been thinking on getting as hub dynamo for my commuter bike (I had one, but trashed the wheel in some tram lines), but the cost of the dynamo and good lights to go with it are prohibitive, I just take some cheap backup light and include some extra batteries in my saddlebag. Rub dynamos are just plain rubbish to ride with
You're exactly right, Alex. Why can't a bike produce its own electricity? Makes incredible sense, especially with all the electronics you need these days. Its bound to happen sooner than later.
Wouldn't inductive brakes make much more sense if you're looking to generate power using the motion of the bike, as on a hybrid or EV, making double use of an existing bike component? Of course, someone would have to actually make such a device to be able to install and use them. But it's basically the reverse of how all smart trainers work, and instead of using electrical power to control the resistance unit, the resistance unit would, well, resist the movement of the wheels and literally brake them, and turn the absorbed energy into electrical power that would then recharge the batteries. You could still have basic mechanical brakes for emergencies or as a backup. Probably the biggest obstacles are weight, complexity and cost, and perhaps legal issues as most countries require functioning mechanical brakes. But it could be done. And while we're at it, why not use all that wasted energy that trainers suck up to control resistance to recharge batteries that would then power the trainer, to avoid those clunky power bricks and allow remote use such as during events like races? I think that at least one trainer already does this.
Fun to play around with. Thanks for experimenting. I wonder if there are any solar options that are 1) easy to mount on bike 2) easy to connect to your various devices? Maybe instead of Cannondale Synapse idea with a battery wired through the frame there is an easy (lightweight) way to have a small solar array wired up to your electronic shifting battery and head unit
Or you could take a toptube bag put a powerbank in it and presto. Stable 5 volts, power charge, could charge multiple devices at the same time. Easy peasy
I suggest looking at Watts or amps not volts. Trickle charge effect - if you trickle charge a battery, it will store the energy for when you need it. So a small trickle charge over a day may charge a 5W charger or more. I suggest a design that stores a trickle charge instead of a direct charge. A concept to discuss. A pocket sized power bank that is connected to the wind powered generator. Although it is often a joke, a helmet mounted generator charging a power bank in your pocket may be a feasible solution. And you can take it into the cafe to charge your phone if you need to. A second idea is to get Ollie to work out where the wind turbine will get the most wind, and work out how to mount the propeller there. A third thing is a gearbox that controls the spinning rate of the propeller. A fourth and maybe less feasible idea is to make a carbon fibre handlebar or stem that has an inbuilt turbine, located in the best place to compromise aeroness with power generated. Last one to generate discussion: A 3D printed mount for the Bike Computer (Wahoo or other) that has an integrated trickle charge mini wind turbine generator that plugs into a power bank or directly charges the battery in the Computer.
Obviously this guy wasn't around in the seventies when you had a friction generator on your bike to generate headlight juice. Yeah it was pretty much cave man tech. To say the least. Lol I guess you could have called it resistance training. Lol
What can I use besides installing a gigantic Dynamo to charge my head unit while it's on and running? My Anker power pack doesn't seem to charge the computer while it's on and I'm not sure why
Think the idea with solar powered lights is, during the day the solar power charges the rechargeable battery and then, at night, the battery powers the light. You won't get more light for longer but, on multi-day trips, you might not have to stop somewhere to recharge. Simples!
Would it charge a portable battery? Once you've got the charge in the battery, the separate units can be charged from there? Could be great for bikepacking off grid 🤔
Axel I'm curious if you can modify the etap charger to charge up battery and use the pins to withdraw power from battery I'm looking to use the SRAM extension cord to have permanent plug in the derailleur and rewire end so use charger case as where to hold battery beside me on a recumbent but also wondered if when not moving that can use the charger like normal to charge the battery (I'm okay if can't do both as be easier than go both ends of recumbent for both batteries)
Just use a proper dynamo hub. There are plenty of great modern dynamos and charging systems. And why do you say people don't use them? I have two and I always see people with dynamo hubs
If only the propeller was made of carbon fibre, and they had sought the assistance of an electronics engineer (not a wizard, someone who understands actual science).
My take on this would be to place impeller as far forward as possible. Reason being keep blades out of the disturbed air, which I believe actually forms a bow wake just a bit in ftont of front tire.
Those bicycle campers you see on youtube have 12v power systems with solar panels generating the power, would these dynamos be able to supplement that?
![Cody Johnson - I'm Gonna Love You (with Carrie Underwood) [Official Music Video]](http://i.ytimg.com/vi/yy9PuYMU29g/mqdefault.jpg)
Would you be tempted to fit something like this to your bike?!
Let us know 👇
Great idea. What about efficiency vs drag when compared to a dynamo hub? I am going to try it on my randonneuring bike. :). If it really works, I would prefer this over hub dynamo. Why I never taught about this? :) I wish had a little more creative mind like this. This is why I love this channel.
@@travelersimports6915 I'm pretty confident the drag is superior here but the real issue is the efficiency of the system.
The frontal area looks to be bigger and the fan shape isn't designed for this job but to move air around so it's using drag (instead of lift, like wind turbine) in order to move. It's also less efficient because the theoretical max energy you can extract from wind it's 59.3%, lifting wind turbine achieve just under 40% tops and drag turbine are usually around 20%-25%.
We can calculate the maximum power available to the fan at certain wind speed by calculate the swapt area of the fan. Looking at the fan mounted to the bike I assume it's diameter to be about 20 cm.
At 20 km/h you have 3.3 watts of wind power, if the fan efficiency is 25% the output is 0.825 watt (5V and 0.165A).
At 30 km/h wind power rise to 11.2 watts, at 25% fan efficiency it's 2.784 watt (5V and 0.56A).
To achieve a bit more than 1A at 5V required for charging the shifters you need to reach about 37 km/h of wind speed.
If you have tailwind you are screwed 😂
An hub dynamo it's only dependent on wheel RPMs so only the generator efficiency and conversion (hubs usually generate AC instead of DC like the fan here) matters and tailwind actually help here!
Not as comparison because of a different stabilizer (and could be really make a difference), just as a single data point, with my SON dynamo hub paired with the Forumslader Pro stabilizer I reach 5 watts of power output (5V 1A) at about 20 km/h, also if I disconnect it for save some of my own energy (long climbs) the drag of the generator is just 0.5 watt.
Try a cylindrical fan
you need a full bridge rectifier circuit on that one. because a generator produce AC voltage. A bridge rectifier turns it into DC to be use for electronics.
As a power source for a bikepacking trip, I‘d prefer a hub dynamo. The new Merida Silex I plan to get even has internal cable routing for that.
You should have put the propeller on your helmet though...an EVEN better look!
😂😂😂
Brilliant fam!
The UCI should make that a rule.
If you’re Conner you’d get even more wind at that height too.
Now that would look cool! 😎
There's nothing wrong with hub dynamos I still use them on my bikes to power the automatic shifting and backup lights. They generate some actual useful power like up to 5W.
Still an interesting idea and fun experiment that little wind turbine.
I have entertained the idea of a dynamo hub for a few years but ended up with a bottle-turned-into-Li-Ion-accus-container (now 4x16850 - but eight should fit too) - because I use different wheelsets during a year.
Hub dynamos are great, they can take away from the bikes rolling resistance but they offer a great solution for those pushing the miles 🙌
@@gcntechwhat’s their efficiency? For 5W output how many watts input is required?
@@MikeMassey-fi5of Good hub dynamos have around 2W parasitic drag (source: cyclingabout). The thing that might not be complitely intuative, is that the "wind turbine" also generates drag (power out + loses). If we are talking about drag on bike using batteries vs bike using dynamo hub, that is different story for a different aplication.
Drag of the hub dynamo is still significanlty less than the effect on roling resistance of the slight differences between road surfaces or tire brand and model, and even the variation in tire presure between two tires or the difference between optimal pressures vs road surface type.
@@matko000 2w drag to produce how many watts output? No way that’s a fixed amount of loss for all outputs.
Why on earth was a brushless outrunner motor shown while explaining a brushed dc motor...different animals entirely. Might need to send an electrical engineer by to check your tickets! J/k keep up the fun video content!
A black fan blade would make all the difference in making iit look cool.
Was thinking the same haha
lol Wallace and grommet come to mind 5.04 into the vid 👍🏻🇨🇦
More cheese Grommet 🧀
Haha, the mouth shape!
Lol at the people taking this too seriously and ranting about dynamos... What can't we just do fun things for the sake of fun?
Agreed! A concept that will help throughout life!!!
pretty sure regular dynamo wastes less energy.
Definitely. Why make a wind turbine when you could just convert rotational mechanical movement from the wheel to electricity. This turbine solution is probably more compatible across all types of bikes, but a dynamo is simply a better soluttiona in every other way.
Normal dynamos (hub or tire contact) are good enough, and there are complete charging-oriented setups available, including regulators. Mostly meant for bike travellers, but useful for a lot of other riders. And the tire contact ones can be folded away, so they don’t slow you down when not in use.
Foldable solar panels plus a powerbank are also quite good if you go bike packing or travel.
A good hub dynamo is less than 1W of additional resistance when not connected. Which is probably less than the additional aero drag caused by the "non-draggy" contact dynamo.
Four ultra riders and tours the dynamo is a great option! 🙌Have you used one in the past?
@@gcntech only on multi day tours - and in the dark past when battery lights did not yet exist in a meaningful way 😉 (like, 30-40 years ago).
Today, I ride with a small powerbank on one-night overnigthers, or through-the-night events like Vatternrundan and such, and hook up my lights when taking breaks (they don’t charge when in use). Mounting the dynamo is a bit of work, so I only do that for longer ones.
You could potentially increase the generating power by increasing the pitch of the blades, and housing the turbine fan in a 3D printed tunnel to guide more air past the blades. I'd like to see part 2 of this, where Aldo takes into account the potential for power loss due to aero drag
Finally a practical use for those marginal gains we splurge big $$$ on! :D
Since most of us already have little devices that use small batteries (phones, lights, etc.), maybe it would make more sense to create a dynamo that stores its energy in a slightly larger battery that could then recharge multiple devices at any time. So one could ride into a remote place and recharge a larger battery, which would then be able to recharge other things. Maybe that would be useful to bike-packing tours.
This is the thing - you can trickle charge battery packs and they are a lot more forgiving than most devices.
It exists... the pedalcell generator is exactly this. Sadly the company had to close due to lack of turnover, but I run one on my bike.
Looks like someone has beat you to the ideas 👀 There is so much cool kit coming out of ultra cycling and touring 🙌
Go to the dark side and dynamo you will never go back. The watts used are irrelevant. The jump on and ride without anxieties of battery life is well worth it. I live wher it get crazy hot in the summers so riding in the dark is most days out. Being able to go out for hours without worry is great.
Being able to run lights all day and night is great
One solution to something like gear shifting could be to use a generator to charge capacitors, they could build up enough charge to execute a few shifts very quickly without adding much resistance, maybe with a very small capacity low power battery that can take a trickle charge to power the "brains" of the system as that side of things likely only requires milliamps/volts.
"Dynamos aren't really used anymore" is rather radical phrasing. You can just get a hub dynamo and switch off the light during the day. No load, no added rolling resistance. I tried it. The wheel spins much more freely once I turn off my lights.
Di2 can be charged via USB and devices that transform the hub dynamo's output into the same power you'd get from a USB port already exist. You could just charge your Di2 batteries as you go. It's not difficult to put together such a system, fully integrated. It could even sync with your head unit to automatically switch charging on and off for maximum battery health. And at sundown it could switch on a pair of lights for safety and compliance with traffic regulations.
The only problem I see is that people won't accept an imperceptible loss in performance even if it means you practically can't run out of juice for your Di2 system or your lights.
EDIT: The current to charge Di2 in its current state might be a little too low coming from a hub dynamo. There are ways around that though. If other batteries can be charged with the current (and they can, I tried it), then you can just use some of those in my hypothetical setup.
Would it be possible to have it only activated when you’re going downhill or only when you’re not pedaling (because then you probably just coasting or going downhill.)
@@ketle369That would be amazing, or even better only when braking. It would be like regenerative breaking.
I don’t brake enough to make it practical to carry the mech around the rest of the time to make regenerative braking worthwhile. But a switch on my front derailleur cable to engage generation only in high gear would save watts I need while climbing, and use them for electrical power storage while cruising and descending when I need them less.
@@ketle369 In short, yes.
Modern head units can be paired with sensors that read your pedalling frequency and your speed. Plus their map data also contains info on elevation. The programming logic to set it up in such a way would also be really easy and certainly no burden for any modern device.
The main hurdle is just that there is by far not enough demand for something like this. Practically nobody serious enough to buy a Di2 bike plus a head unit wants a dynamo "slowing them down". And it also looks different than standard hubs which is a cardinal sin in their view.
@@anwidocu I don't want to sound overly negative but there are a number of problems when trying to implement it that way.
A hub dynamo is rated for like 3W. If it's only engaged while braking it might as well never be.
For regenerative braking to work, you'll need a much beefier dynamo but they are actually going in the opposite direction. LEDs need less power so they went from 6W down to 3W which is obviously going to do nothing to slow you down.
And if you decide to go with big beefy dynamos that properly slow you down and create meaningful amounts of energy to charge your devices, you'd need some kind of huge buffer battery to store that spike in energy to then slowly feed what you're charging.
I'm unsure of the exact dimensions of such a system but it would certainly weigh several kilograms at least. BTW electric cars need traditional brakes because the regenerative ones aren't strong enough on their own in an emergency.
Difficult climb? Just flick a switch connecting your D battery to the propeller and relax with your hands behind your head as you're rocketed up the hill.
"Dynamos aren't really used any more." Maybe not by by boy racers, but doing a 1200k Audax on batteries is a royal pain in the butt. A small hub dynamo allows you to run your GPS with back-light and charge your phone as well as providing brilliant, care-free light fore & aft, and with a photocell in the headlight you don't even have to bother about switching it on.
BTW, WW1 biplanes used gadgets like yours to drive airspeed indicators.
Some aeroplanes actually have this sort of generator that can be deployed in a total power failure. Just to keep the vital electronics going in a worst-case scenario.
@@Ed.R Interesting to know. I guess a hub dynamo in the landing gear wouldn't really hack it. ;-)
10 kudos. This is the nerdy stuff we all contemplate with our post-ride beer. Excellent.
Roadies will do almost anything to avoid using practical equipment. Dynamo hubs, steel, alloy, pannier bags and racks, handlebar bags, round seatposts, separate bars and stems, headset spacers, externally routed cables, mudguards.
I’m half joking. But seriously, you could just buy wheels with dynamo hubs. They’re great and can be less of hassle than having to remember to recharge your lights. Great for commuting and cycling touring. It would actually be nice for GCN to do a video on dynamo lights or create more content that isn’t focused on expensive racing bikes.
This should be on Hack or Bodge of the week xD
Given that it's fastened with cable ties, it's by definition a bodge 😉
Needed to be red so it would spin faster
It's pretty optimistic trying to get 1 amp from this motor. Modern batteries can actually hold pretty significant charge, and trying to charge them is harder then it looks. In you shows you often measure a power output on pedals. As I recall 200 Watts is about you usual power on tests. So leisure riding might be about 100 Watts? Shifter battery has about 500 mAh. So to charge it you need 5 Volts * 0.5 Amp = 2.5 Watts for 1 hour. If you using dynamo you can easily multiply it by 2 to account for energy lost on friction and voltage conversion in charger. If you use propeller, there is no magic: you would still lose same amount of energy in form of air drag, is fact you probably lose even more with propeller. So about 5 Watts for an hour? Don't even think about charging the phone with 5000 mAh, it would be 10 times more! So better just carry a spare battery or power bank and spend those watts on actual riding.
What You produce is less than You loose!!! Want to produce 20 w for charging you would have to put 30w in coming from your legs... which means that going up the hill you would be loosing your breath faster 🙂
I am surprised that electronic group sets are not self charging. It would be relatively easy to incorporate charging at the jockey wheels, and the power loss would be very minimal. Even 1W of charge would be far more than needed to maintain the battery.
I cannot believe you went to the trouble of researching and making the generator and not test it/prove it in the real world just because it was raining🤔
Any proper cyclist would have gone out in the rain to check it or at worst waited for a time when it had stopped raining....
Very disappointing, not sure I can take GCN seriously any longer🙄
Voltage with very low amperage won't help. You better use wheel or crank to generate electricity. That'd be more efficient.
Nice experiment
the trick here is to just set up a power bank system, then have your riding group friends carry extra power banks that way you don't have to carry the weight just like some riders rely on other riders for tools and spares.
Of course we all know a couple of riders whom talk and preach about carry tools and spares and then don't 🤣
Me personally if I needed a power source I would fit a dynamo hub if I needed that extra power while riding, but I don't use a head unit at all, if I need lights which is not very often I have nice bright ones for tha,t as for the phone I have a power bank for that and if Im doing my bicycle-train commute then I just being a cable and plug into the train's usb port, my new phone can go all day on a charge, Im not using it while I'm riding my bicycle, I like my alone time on the bicycle, that's why there is text, email, voice mail and DM if someone needs to tell me something or give some information.
cheers
PS next experiment should be attaching helium balloons to a bicycle to make its feel lighter although getting traction from the tires might be an issue. 🤣
use a 3.7v li-ion battery as an energy reservoir, charge it up through a BMS board by the windmill, use a boost converter to convert 3.7 v to a stable 5v for the shimano battery to draw current, this is how the config: Windmill -> BMS Input -> 3.7V Li-ion -> BMS Output -> Boost Converter -> 5V -> Shimano battery
the more number of 3.7v batteries running in parallel, the larger the energy reservoir is and the more stable the current than can feed to Shimano, however the heavier the setup to be carried on your bike
I used to use dynamos because I am very very old. They eat the sh&t out of the sidewall - and they *also* take a fair bit of extra power to do anything useful - back in the day it was incandescent bulbs, and so most of that energy went to heat, which was a really, really depressing way of making a pretty feeble light beam.
Why deal with the inefficiencies of coupling a fan to the air when you've already got two wheels reliably spinning round?
the last time Alex had a flower-power "generator" on his bike he had vortex-generating tassles too
This is, perhaps, the best GCN video ever. Great work Alex!
Wow that is a big claim! What's the second best? 👀
Anything with Alex and his wife in it! love those silly geese! @@gcntech
I tried the same thing with a computer cooling fan for a college project (and to save me buying a new disc brake dynamo wheel!) and had similar results. Everything worked on the bench, but out on the road it didn't seem to be a reliable enough power supply
Love this stuff! It's a fun, simple experiment.
Keep diving deeper into this stuff and make an endurance beast bike... think bad lands endurance race or the ultimate apocalypse ( bikepacking) machine but keep it aero as possible.-you're not building a rock.
-Solar panel disc wheels with tape cabling up the trailing edges and an internal inverter and hub on the cross bar.
-Mount electric, waterproof, airfoil panier bags with pockets to hold stuff to be charged...and your clothes/tent dry.
-You could even power an electric lunch box and route the radiant heat to heat up a small internally routed fluid filled tube to warm the bike frame and rider on cold days- think radiator on a car. Controlled by a thermostat on your headset. Nothing like heated saddle and warm feet on a long freezing bike ride.
I'm not sure how to get that slashing through words off above.
Where else can you recapture and convert wasted energy on your bike? What can you convert it to?
By the way, it seems like you were trying to figure out your resistance drop when an electrical circuit is under a load. Start with Ohms law and figure it out from there. E=IR or R= E/I where E=volts, I=amps, and R=resistance.
You put a hyphen at each end of the strike throughed text. Google, "RUclips comment markdown" if you want a more thorough explanation.
Think a space before the second hyphen (or a new line) would be what you're looking for. (I'll do an experiment below).
No gap
-Strikethrough-
Space after word, before second hyphen
-Strikethrough -
"Enter" for new line after word.
-Strikethrough
-
Props are highly inefficient ... I would estimate that half of the energy is lost in additional resistance
Alex fails to understand the need for lights in the day time? That's embarrassing!
A motor that small to use as a generator, at 5V, the ampage is quite small. It's quite possible that lights, a phone or head unit battery requires significantly less than 1 amp to begin to charge (albeit slowly).
Time for a trip to the wind tunnel! Maybe put it behind you so it can work off of already dirty air rather than the cleaning air up front.
I would think a better engineered fan blade would help.
What are you suggesting... this is top level tech 🤣
law of conservation of energy - we don't create or make electricity we convert kinetic energy to electrical energy. Energy can neither be created or destroyed
Well, you can spot the non-bikepacker on the GCN team. "Dynamos aren't really used anymore." 😂❤
Alex, I would suggest using the fan generator to charge a powerbank battery - these are more tolerant of variable energy sources. And then using the powerbank to charge your phone/gears that are a lot more fussy about voltage and current.
Could work with a much larger battery without a regulator. At some point, the voltage of the battery would again stall the generator. Also needs a blocking diode to prevent the thing from becoming a fan.
Alex the problem with things not charging is likely because the generator won't be able to provide 1A. Most devices test the USB before starting to charge. They load it with more amps until the voltage drops too far below 5V. From that they know what current the charger is capable of. Some devices are OK taking a small current but some clearly have a minimum threshold. Its odd about the shifter battery as it will be small so should only require a small current unlike a phone battery. Maybe there is more to it and if USB C is involved there definitely is.
It would sell to roadies if it was made out of carbon fiber, though.
Charge a known working battery that you can then relay that charge to the di2
I certainly hope this will appear on Hack/Bodge of the Week! But I've got to say that I fall on the side of bodge. Hub dynamo is clearly the way to go here. Right from the beginning I was thinking "That's a pretty small fan. How much current are you going to be able to generate?" I also suspect it's quite an inefficient way of generating electricity given that you already have a rotating wheel. Still, it looks like a really fun project! It's the type of thing that would be awesome as a science fair project.
Great video! Thank god for the hub dynamo. Never ever seen anything on that on GCN, thought....
We would love to investigate the dynamo more 👀 We got to check out these Hunt wheels a while ago 👉 ruclips.net/video/H5OouNUP77w/видео.html
You could generate infinite volts from that fan if you could spin it infinitely fast, but you'll never get 1amp out of it unless you cut the resistance by half and leave the voltage unchanged, then you will double the amperage across the circuit. Probably still won't come close to 1amp though.
I find it so practical to carry a portable power bank with me on the long rides that I do not care much about adding anything to generate power on the go. There are solutions that even fit inside the handlebars and hold up juice pretty enough to power anything on your bike.
I also thought about such a device integrated into the frame. Might also be coupled with small solar cells. Or use more ventilators.
But a dynamo in your front wheels is best. No need to invent the wheel again.
Is it April 1st already ?? FFS - the size of that 😂 …. The answer, which you mentioned at the start is a dynamo
No jokes here 😉
Just charge power banks, there's also bar extension for accessories with in built power bank, charging the thing the fans hanging on
Cool, if silly, experiment. As many others said, I think you need to have a central power bank...that way your fan dynamo is trickle charging that, and you devices get an even charge.
The other solution is to set up your bike like the boy from Kiki's Delivery Service....you clearly need a bigger fan!
That was a very interesting exercise. Well done, Aled. That said I'll stick with my Garmon 1050 solar and SON hub for my lighting needs.
The maximum power that can be extracted from the wind is defined by Betz's law P = 8/27 pv^3 A.
Using a 10cm diameter fan at sea level, that means you'd need to go 32.4kph to generate the 2.5W you need to fully power a USB 2.0 device. And that's max theoretical efficiency! It only gets worse from there once you start to take stuff like the aerodynamic efficiency of your fan, the efficiency of your generator into account.
If you want to make this work your first step would be to get a much bigger fan.
"Dynamos aren't really used anymore" - What world are you talking about? In this our world dynamos are totally being used, sometimes even on bikes with an electric motor, that already brings a big battery! And really, if I didn't chose very special tech, that is actually incompatible, I would have a SON dynamo on every bike, except the electric cargo bike. And I would use it for lights and USB with available hardware and it would be great. I am really often thinking about going back from my special stuff, just because I want the dynamo.
I love these little hacky projects from Alex. They're maybe not as ambitious as Blake's but I love that they're always exploring interesting ideas. More please!
That is not working at all.. You need the specification of that little motor? A real charger is able to put at least 5v 1amp. The amp is very important. Your little motor is rated for what?? 5v 0.2amps?? 12v 0.5amps?? What is the max RPM of that motor?? If the wind is get the motor RPM higher than the max RPM you will lost amps.
Well done! Appears you have a lot of people thinking of creating new or bringing back old technology. I had similar issues commuting in the cold weather when the temperature dropped below 0 C and my light batteries only lasted about 75 minutes. Solved it by purchasing a 5v 2A lithium battery weighing 1800 grams. Fits neatly inside my jacket to stay warm when ready for use. Warmer weather it fits neatly into my tool bag under the saddle. Cheers!
So if you are charging 5 V with > 1 amp you need … 5 VA of power, aka 5W. So at a bare minimum you need to be willing to push 5 extra watts for some amount of time to get your gear charger to give you another “zzzit”. Don’t know how many joules are needed per “zzzit”
Most electrical devices are not happy with constant changing power (voltage or current). From different riding speeds you get different power output. Most electrical devices will stop charging after a short time. You probably need a regulating device that charges something like a buffer battery. From this buffer battery you can get a constant output for devices like a smarphone. There are other workarounds and ideas from the people that use dynamo hubs. Dynamo hubs are still in use and popular with other forms of cyclists. You barely see them on road bikes, what GCN is all about. 🙂
Great idea! Perhaps invent a device that collect the wind speed aerodynamically in areas that make you ride faster, without increasing the price of the bike by 5-10K.🙂
Good idea. for touring and randoneuuring I use a Pedalcell generator, a more advanced (and efficient) version of the old dynamo. It's a great bit of kit. sadly the company has closed... lets hope they resurface soon. For most riding applications you just don't need it, especially with the good battery banks available these days.
Interesting proof of concept. Making usable voltage unloaded is one thing but being able to maintain it under load with the counter-emf applied is another. 5 volts at 1 amp is 5 watts. That's five watts of electricity out, not five watts of input. With conversion losses and other inefficiencies factored in (nothing is 100% efficient), this setup likely takes at least 10 watts of input on the turbine to function. Still, I could see something like this being used as an emergency power source.
Hi Alex, Have you tried gearing it up? Instead of direct drive to the shaft, use gear to spin the shaft faster? (Did I confuse you by using your actual name? LOL!)
This was a lot of fun, well done Alex. One use for this I could see is for those month or year long adventures rides into remote wilderness, however, a hub dynamo might work better. It was still a fun science experiment though. How long until you decide to head back into academia and start working towards that PhD?
Ohyeah, dynamo hubs are not gone at all, they've just never been a part of the racing culture for obvious reasons. Time to expand your horizons, GCN
"Dynamos aren't really used anymore and that is because battery tech has evolved a huge amount over the years"
Um the majority of people I know in my city with a city bike have a dynamo for lights.
Nice science fair project! Probably could be made to work if the output could be pulsed! Same generator, way below its potential, but wouldn't stop the mill completely after a tiny current passes. Very low output.
I've been thinking on getting as hub dynamo for my commuter bike (I had one, but trashed the wheel in some tram lines), but the cost of the dynamo and good lights to go with it are prohibitive, I just take some cheap backup light and include some extra batteries in my saddlebag.
Rub dynamos are just plain rubbish to ride with
You're exactly right, Alex. Why can't a bike produce its own electricity? Makes incredible sense, especially with all the electronics you need these days. Its bound to happen sooner than later.
Fun vid! I use a Shimano 1.5 watt front hub dynamo to drive a very adequate led running light directly.
I have considered a hub dynamo for my bike. I'm shopping for information right now although I don't know if I will purchase one at the moment.
Wouldn't inductive brakes make much more sense if you're looking to generate power using the motion of the bike, as on a hybrid or EV, making double use of an existing bike component? Of course, someone would have to actually make such a device to be able to install and use them.
But it's basically the reverse of how all smart trainers work, and instead of using electrical power to control the resistance unit, the resistance unit would, well, resist the movement of the wheels and literally brake them, and turn the absorbed energy into electrical power that would then recharge the batteries. You could still have basic mechanical brakes for emergencies or as a backup.
Probably the biggest obstacles are weight, complexity and cost, and perhaps legal issues as most countries require functioning mechanical brakes. But it could be done.
And while we're at it, why not use all that wasted energy that trainers suck up to control resistance to recharge batteries that would then power the trainer, to avoid those clunky power bricks and allow remote use such as during events like races? I think that at least one trainer already does this.
Fun to play around with. Thanks for experimenting. I wonder if there are any solar options that are 1) easy to mount on bike 2) easy to connect to your various devices? Maybe instead of Cannondale Synapse idea with a battery wired through the frame there is an easy (lightweight) way to have a small solar array wired up to your electronic shifting battery and head unit
Or you could take a toptube bag put a powerbank in it and presto. Stable 5 volts, power charge, could charge multiple devices at the same time. Easy peasy
I suggest looking at Watts or amps not volts. Trickle charge effect - if you trickle charge a battery, it will store the energy for when you need it. So a small trickle charge over a day may charge a 5W charger or more. I suggest a design that stores a trickle charge instead of a direct charge. A concept to discuss. A pocket sized power bank that is connected to the wind powered generator. Although it is often a joke, a helmet mounted generator charging a power bank in your pocket may be a feasible solution. And you can take it into the cafe to charge your phone if you need to. A second idea is to get Ollie to work out where the wind turbine will get the most wind, and work out how to mount the propeller there. A third thing is a gearbox that controls the spinning rate of the propeller. A fourth and maybe less feasible idea is to make a carbon fibre handlebar or stem that has an inbuilt turbine, located in the best place to compromise aeroness with power generated. Last one to generate discussion: A 3D printed mount for the Bike Computer (Wahoo or other) that has an integrated trickle charge mini wind turbine generator that plugs into a power bank or directly charges the battery in the Computer.
Obviously this guy wasn't around in the seventies when you had a friction generator on your bike to generate headlight juice. Yeah it was pretty much cave man tech. To say the least. Lol
I guess you could have called it resistance training. Lol
What can I use besides installing a gigantic Dynamo to charge my head unit while it's on and running? My Anker power pack doesn't seem to charge the computer while it's on and I'm not sure why
Think the idea with solar powered lights is, during the day the solar power charges the rechargeable battery and then, at night, the battery powers the light. You won't get more light for longer but, on multi-day trips, you might not have to stop somewhere to recharge. Simples!
Would it charge a portable battery? Once you've got the charge in the battery, the separate units can be charged from there? Could be great for bikepacking off grid 🤔
Axel I'm curious if you can modify the etap charger to charge up battery and use the pins to withdraw power from battery
I'm looking to use the SRAM extension cord to have permanent plug in the derailleur and rewire end so use charger case as where to hold battery beside me on a recumbent but also wondered if when not moving that can use the charger like normal to charge the battery (I'm okay if can't do both as be easier than go both ends of recumbent for both batteries)
One of those fair ground windmill on a stick toys instead better wind capture efficency and lighter too. 👍🏻
You can't charge your bike gears because there isn't enough current generated. Voltage is half the battle. Notice your phone charges slowly.
Never put a load on it before regulation??? And of course bigger blades would have more push ...
Just use a proper dynamo hub. There are plenty of great modern dynamos and charging systems. And why do you say people don't use them? I have two and I always see people with dynamo hubs
This video is on my current watch list
A shocking video but there's no charge to watch it so I'll watch it
This concept could work instead of the little flag that people put on baby / dog trailers. You can generate power as well as provide visibility.
If only the propeller was made of carbon fibre, and they had sought the assistance of an electronics engineer (not a wizard, someone who understands actual science).
I just carry a small Anker Powercore battery in my fanny pack. Cool project though!
My take on this would be to place impeller as far forward as possible. Reason being keep blades out of the disturbed air, which I believe actually forms a bow wake just a bit in ftont of front tire.
Cool now sell it 1500€ since it's for you normal prices of today's equipment haha
Those bicycle campers you see on youtube have 12v power systems with solar panels generating the power, would these dynamos be able to supplement that?
From a bikepacking standpoint this might work as a method to charge up a powerbank.
There are some laws of thermodynamics involved here, like the 2nd. Nothing is free! Ask Ollie.
I think it would power much more efficiently if it had larger fan blades
With the di2 charging, you found out the issue of current vs voltage. It’s like heading up hill…
Please tell me why is there no phone charger ports on turbo trainers? People pushing 200Watts for many hours should be used to charge gadgets!
you can compite in the hack or bodge contest. Did you check how many watts it make you loose?
fun vidéo thank you
solar bike light maybe good for ultra endurance, multi day. You can charge your light with the sun during the day then have battery when it gets dark.
33 years old?! I knew Andrew and I should be friends. Just one more thing we have in common 😁