GCN Tech I do and it powers my automatic shifter. As it charges a couple of 18650s I can also charge my phone off it with a little voltage convertor circuit.
GCN Tech It wasn't really made clear in the video but before connecting a dynamo to a battery its important to check if the output is AC or DC. Most dynamos I've come across put out AC so it's essential to use a rectifier between the dynamo and battery.
Calvin Pessl Just some old ones from an old laptop battery, I'm using 2 cells in series. Mine really has one purpose which is to power the automatic shifter. The 8.4 volts is perfect for an Arduino and a servo. Left a comment below asking if anyone knows the optimum voltage for such a battery pack.
An AC-DC "converter" is called a rectifier. It's not something anyone needs to know, but when you do know it, you can never help but correct those who aren't aware of it.
On a normal electrical generator the electricity is gathered from two different ring contacts (separated on the axial dimension) with pads that are in continuous contact. The dynamo uses a single ring contact that is cut in two halves (half rings) and pads on the opposite sides of the ring. As the dynamo rotates, the coils will produce alternatively a positive and negative polarization, but as the ring rotates the pads will contact first one then another coil (dynamos work on two coils only). Disadvantages of dynamos: mechanical complexity, the magnets are fixed so you need to rotate the coils and gather electricity from them (increases electrical and mechanical losses), they need one collector ring for every two poles so most are bipolar, when rotating a bipolar generator you have peaks and troughs in the necessary force (they don't roll smoothly). A magneto can have the magnets on the moving part of the device so no mechanical and electrical losses on the collector part, can be made with multiple "pols" (phases) so the peaks and troughs are much lower, rectifiers are gonna work forever at peak efficiency (unlike mechanical systems with brushes collecting electricity).
I love how Ollie puts on a Midwest American accent when he wants to sound like a scientist. Those of us across the pond typically don an RP British accent when we want to sound smart. Hilarious!
This would be really cool. The video was good, but I felt we needed to see a dynamo/magneto in use and actually charging something to fully grasp how cool it is.
Shannon Ayres his also becoming my favourite mathematician. 440 grams is nearly four times 96 grams. Got to love the British education system when apparently Ollie has a PhD.
Dynamos are awesome! I've been using a Shimano Alfine dynamo hub with B&M lights(front and rear) on my commuter bike for almost 2 years and the lights are great to have whenever I want. They are also pretty bright compared to alot of the midrange bike lights I've used in the past.
Boo! What a mundane use-for-everyday setup! Imagine all the grams you are wasting! I'm joking of course. I have one bike, that has to do it all. So I have fenders, a pannier rack, fixed lights, the works. Seeing the nerds on GCN discuss losses of half Watts and weight savings of grams makes me chuckle.
Dynamo hubs are totally the way to go. I have only used them with LED lights. I have never tried to charge devices. I have used a vintage Sturmey Archer, a new Sturmey Archer and an SP. They all delivered bright reliable light at night.
I know vintage dynohubs are easy to service, despite how scared a lot of people are of them, but I'd imagine modern ones with sealed or press fit components are much less straightforward, and have no better spare parts availability than one from 1936.
Absolutely the best upgrade I have made on my commuting bike. The power is always available and the lights can be permanently attached. Just be sure to get lights with a capacitor/standlight so you aren't left in darkness when you stop at traffic lights.
I have one on my Litespeed and it’s awesome and drag is so negligible I leave the light on permanently. Highly recommend K-Lite headlight specifically built to suit.
Thanks for the video. At the time Sturmey Archer trademarked Dynamo cars also had Dynamos that was in the 1930s. I begged a 1950's 3-speed dyno-hub in order to answer some questions people were asking in some of the vintage and near veteran bike Facebook groups. The losses in a dynamo which is electrically simply a generator are Copper losses in the case of an AG/FG/GH are 5 ohms which when drawing current (300mA) is 1.5W = 5 x 0.3 Eddy current losses these depend on how thin the laminations, which minimise current circulating in the iron by breaking the circuit that would be made if it were solid mu-metal, the soft iron, conducting fluctuating magnetism to the winding. A mains transformer and good motors have quite a thin, and therefore efficient, compared to a dynamo. I do expect that the dynamo is not particularly good. I am told of one modern hub dynamo that makes the bike much harder to peddle when the bike is ridden at speed when the AC generated is a higher frequency than 50Hz mains. This may be due to this issue? Magnetising current - the power needed to keep changing the polarity of magnetism - for mu-metal this is very good. blog.andrew-lohmann.me.uk/2019/07/bicycle-hub-dynamo-maintanance-project.html But I have a question does a 3W dynamo provide enough power for all the lights and IT. The answer is going to be no but will it be enough for the average person bike lighting and provide enough to top up his phone a bit?
I kept waiting for you to tell me that I could win this wheel, which would have been tremendous, but you didn't, and now I'm sad. I'll tell you what, if you want to make it up to me, you can send me the wheel.
I love my hunt dynamo wheelset. The drag is negligible, and it's a nice piece of mind to know that your lights won't run out of batteries. Oh, and one minor correction: the dynamo hub generates AC current, not DC. This is why the lights tend to flicker at slower speeds. In fact, if you freeze the frame at 3:18 you'll see a neat little sine wave on the flange letting you know that you need an AC to DC converter for your USB devices.
When I was a kid I used love my old bottle dynamo(s) I had this awesome front lamp on the right hand fork that would light up tree canopy dark roads in Bedfordshire. My mates had these crappy Ever Ready battery lights that used a pair of AAs that were just no comparison. The last time I used one was around 2000 but was experiencing problems with the contact wheel slipping on the tyre in the wet and without a proper mounting boss on the fork used a hacked solution that utilised a bracket that used the cantilever boss. Just use modern LEDs now but when I spec up a new touring bike, probably a Condor, I'll have one of the Son hubs. As others are saying though it is necessary to add somekind of circuitry to maintain steady current.
I have a Son28 dyno hub, hooked up to a Supernova e3 triple heads light and a e3 tail light. I also have a sinewave Revolution usb charger. This setup was expensive but its worth it knowing that I have lights any time I need them, and I can charge a powerbank witch I can then use to charge my phone, ipod, gopro and gps while I'm out touring.
I've got the SON delux with Edelux2 and Sinewave Revolution and a battery pack that allows for pass-through charging. It is expensive but knowing that I can run all night is good piece of mind.
I grew up in Romanian in the 80s. Many people depended on public bus, trains and personal bikes to get around. They had these dynamos back then. My grandfather had one on his bike he rode to work and back.
+GCN Tech @6:35 Not necessarily true. A magneto doesn't always produce ac current, for example an ignition magneto on 2 stroke engines produces a dc pulse.
I have a son dynamo hub on my gravel bike with an edelux light and a Shimano Nexus with a non branded plastic light on my commuter, I love dynamo lights, not worrying about batteries is excellent. I want to upgrade my mountain bikes to dynamo lights too.
I would not charge even a batterypack with a wheel dynamos without having a circuit that keeps the voltage at a steady USB-standard of voltage and current. The dynamo on the HUNT wheel seems to have 6volt output at 16km/h, so If I assume correctly, it means it will output even more going at 30km/h and therefor can damage the electronics you try to charge.
Andrew N yeah I heard your have to regulate the voltage and current somehow because it can spike during riding. But then can you can charge your phone directly from that voltage regulator? Or do you have to charge your battery pack first then your phone? Because that kinda seems inefficient imo
Generally the voltage is self regulating to an extent because the efficiency of the generator decays as the speed increases, it's how they generally avoided blowing bulbs going down hills while still having lights going up them. As a result, it doesn't take a lot to get a totally smooth output, you just need to bridge the terminals with a suitable resistor.
Which begs the question: why hasn't a clever dynamo manufacturer built the regulating circuitry right into the hub so that the output could be used directly to charge USB devices? A sort of "iDynamo"?
Paul Flory depending on the circuitry it may not work within a close proximity to the magnetic field that's being radiated from the dynamo and the hub most likely also has a lot more vibrations than the frame of a bike which could add unnecessary wear to the circuitry, especially soldered components on a small PCB.
I thought about going dynamo on my adventure (gravel) bike set up but for all the extra cost and effort it just seemed easier to get a solar rechargeable battery with 25k mAh which lasts 3-4 days. If you intend to cycle through the night or go a very long time in crap weather and no access to electric then I can see why you would usea dynamo.
Przemyslaw Sliwinski -- di2 is charged through a normal USB connnector, so yes, you'd charge a battery pack first. Then plug battery pack in to di2. Battery on di2 lasts a flipping long time though so unless you're cycling around the world in 80days and don't see a single plug, you shouldn't need to charge it
'...that's nearly four times more.' Um, it's actually 4.5 times more than 96g. Great video nonetheless Ollie as been wanting to know about the benefits and drawbacks of dynamo hubs for a while.
It will depend on load power, so without electric power meter connected between dynamo and battery pack or charger you will never know how much power is used to charge power bank, because of charging Li-ion batteries for example in non linear process with current much lower at the end, so wthose power ratings on those dynamos whatever it is can be only some kind of capabilities of such things what they can do and how much power you can take from this thing but it can't tell you without electric power measurement how much drag power it uses at the moment ;) It is worth to know basic electronics anyway and do not relay on Yt video like this one because of you can miss many important things while presenters in GCn have sometimes pure understanding how physics works :)
@@szankony6276 "presenters in GCn have sometimes pure understanding how physics works" While Szan Kony seems to have poor understanding how English words work. SCNR ;)
I carry a small solar panel on my rando bag. Works for me, but I also don't have many gadgets other than my cell phone and my Roam. The cell phone I keep off during my ride. I used to ride lots at night but after a couple of spills I shy away from night rides.
thanks but would've liked some info on output and what sort of limitations on the amperage you can pull from these, as well as different models and specs. on to the next vid on these...
Standard requirement for a lighting dynamo is three watts at moderate speeds (.5 Amps at 3 Volts) Most current hub dynamos will easily deliver up to 6 Watts. With special charging circuitry like the dynamo harvester you may squeeze out up to 12 Watts. (At the standard USB 5 Volts in this case.)
6 Watts of drag at how much electrical output power? It depends on the load you're drawing. I can't afford the SON kit so I use the Shimano ones, they're fine as long as you stay away from the "DH-32" model that's nfg. You can get phone adapters with rectumfryer and surge protector that let you charge from the dynohub without intermediate powerbank, LiPo batteries are pretty efficient but you always incur at least 10-20% loss by storing the energy in a battery and then getting it out again.
You didn't include anything about connectivity, lights, chargers, power banks. I know some basic stuff about electronics and I can tell that no gadget uses 6V. USB standard voltage is at 5 +-0.2V and 3W is close to half power than a basic USB 1A charger. I suggest you do a follow up video on everything about the peripherals of a dynamo.
Many gadgets can easy step down to 5V from 6V, so it is better to have 6V than 5V, because of one need to regulate voltage level to 5V with different tolerances, so having 6V is advantage, because of one do not have to step up to higher voltage before using eg. linear voltage regulator which need slightly higher voltage than 5V to step down easy to 5V. I'd like to see test where you connect multimeter with small load lets say 1W at see if those wheel dynamos whatever it is called have some step up converters which will help output 6V regardles of cruising speed in soem range lets say between 10km/h to 90km/h ;)
My guess is that you’re too young Ollie to have seen Brains on Thunderbirds when it was first broadcast but thanks for an entertaining impression of Brains.
I've got a cheap and nasty bottle dynamo on a city commuting bike. I've noticed that whenever it rains the dynamo doesn't produce enough power for my lights. (I suppose either water is getting underneath the bottle top or possibly the water between the tire and the bottle top is causing the issue) I've also got to cycle up a steep hill and there's always that bit of resistance whenever I use a bottle dynamo. Would a hub dynamo get around these issues? If so, how is one installed? Do I need to buy a brand new wheel rim?
Hunt (and probably others) sells wheels with a dynamo. You could also buy a dynamo by itself and have it built into a wheel you already own by your LBS. Just make sure they each take the same number of spokes.
Too bad no links for all that were mentioned. Are these brushless or brushed in transfer? If these dynamos had enough output, they could help charge a battery on an electric bike to extend range.
Different hubs work differently because of patents and what not, but the classic and class defining Sturmey Archer GH6 uses a 20 pole magnet which bolts into the hub shell and then has a copper wound armature which sits within it and is clamped to the axle by the lock nuts. The wires connect to the armature which is stationary as the magnet spins around it, I imagine that modern ones operate in a similar way.
I saw that someone below mentioned installation and use video. Did you ever make one ? Can I have one on the front and the back ? If you have time, that would be great. I need to figure this out, and instead of me dinging around and messing up, it would be great to just watch a video instead.
Drawbacks for hub dynamos: weight, drag, and......price, low output and maintenance. I believe both SP and SON hubs have to go back to the manufacturer for bearing replacement, which, if you ride a lot of miles, could be every 1-2 years. And the hub has to be removed from the wheel for that.....so then you have to have the wheel rebuilt. And the amount of light you get with a hub dynamo light is pretty sad compared to a battery light system you can put together for $30, as I have. And I can move that battery system to any of my bikes, even though they have different wheel sizes/brake systems. I really want to like dynamo lights, but I just can't get past the hundreds of dollars extra cost for far less performance.
"Dynamos are for charging IT devices, or charging lights. Or driving lights directly!" Sign of the times, I guess... Also, complaining about the drag of a switched on dynamo: It's physics, dummy! Also known as the law of energy conservation. On the longest tour I have ridden up to now I had a 'be on' dynamo harvester charging device (now available from NC-17) that actually extracted up to 12 Watts out of my SON. And if you carry a lot of electronics, as we tend to do these days, you are happy about every single one of these watts. That's why you don't want the delux version of the SON on a tour. Yes it's a bit lighter, but it also extracts less power. Go with the 28. ETA: The NC-17 AppCon 3000 unfortunately is not nearly as powerful as the dynamo harvester. They claim that they have optimized for slower speeds (below 15 km/h), which are more common on tour, but frankly, it's not all that more efficient there to warrant the change. The best charging device today is the Forumslader ( forumslader.de ) If you need high power.
What I'm curious about is if it is a brushless design or not, which would be WAY superior to anything else out there and much more efficient. I looked at one of Hunt's videos and it showed the guts of one and it does look brushless, hence no commutator. It that is the case, it would actually be an syncronous alternator and use a rectifier internally. That would be slick indeed and be practically maintenance free... except for the bearings. But somehow, "syncronous rectifer" just doesn't roll off the tongue, does it!?!? It's the antithisis of a sexy name. Yeah, stick to Dynamo.
The DC coming from the dynamo will most definitely damage your phone because a Dynamo creates AC. That's why you need to buy a device to convert it to DC (A rectifier) before you charge any device.
At 00:30 you see two rectangular pins next to the axle. That where you put the connectors on. A shimano connector looks different and is easier to use.
Is there an easy way to determine how large of a power bank you can charge on a ride of a given distance with a dynamo? Could you charge a spare e-bike battery for a bike-packing companion on an e-bike?
At 00:30 you see two rectangular pins left of the axle. That is where you put the connectors on. You still need some sort of charging device, like a bm usb werk, cycle2charge, etc
For what its worth there is big differences between a Magneto and a Dynamo . A Magneto produces AC voltage with permanent magnets and a Dynamo produces DC voltage using a commutator ..
Also, of course, watts are watts. Assuming that the dynamo is efficient, a dynamo that cause more drag will charge your devices faster, up to the maximum number of watts the battery can accept. By the way, you forgot the number one reason why bottle dynamos are horrible: Slippage! They might work well in the dry, but once things start getting wet and cold, they will invariably start slipping. So you go to your local bike store or read something on the net about a new miracle dynamo that won't slip, you buy it, and it doesn't slip. Not for the first week or so. Then it's back to square one...
I tried charging battery pack using dynamo hub, but it goes awfully slow. Not recommended. Charging iPhone or Wahoo ELEMNT directly from it, works perfectly.
The drag is actually much greater than the amount of watts they produce, that hub probably creates 10.5 watts of drag when producing 6 watts of energy. They are no where near 100% efficient.
A fantastic video for people who already know everything suggested by the title. For others wanting to learn, not so great.... no description of exactly what it is to a cyclist, no view of how it connects to the bike or how it's actually used in practice. It's said that you can use them to charge equipment like phones and computers and heated blankets(?), but not even the slightest hint at the charging capacity (e.g. a 10-minute ride will charge your heated blanket for a toasty night's sleep?). Not up to GCN standards.
They get pretty bright with LED technology, modern dynamos will output 6V at 3W (0.5A) AC, which is plenty. Even with classic dynohubs, which were killed by the 1985 Road Vehicle Lighting Regulations, the light output using leds is easily comparable to battery powered lights. The things to watch are standlights and rectification, which some lamps will have built in but which can be annoying if missing, dynamos don't keep the lights on at traffic lights by themselves, and without a rectifier, all leds will strobe.
They get pretty bright with LED technology, modern dynamos will output 6V at 3W (0.5A) AC, which is plenty. Even with classic dynohubs, which were killed by the 1985 Road Vehicle Lighting Regulations, the light output using leds is easily comparable to battery powered lights. The things to watch are standlights and rectification, which some lamps will have built in but which can be annoying if missing, dynamos don't keep the lights on at traffic lights by themselves, and without a rectifier, all leds will strobe.
If someone is intrested, there are some nice information on some dynamos on: fahrradzukunft.de/14/neue-nabendynamos-im-test/ Its german but you should be able to comprehend the graphs in the lower part of the article: (1): mechanical input lights off (2): electric output on 12 Ω (3): mechanical input on 12 Ω (4): electric output on 24 Ω (5): mechanical input on 24 Ω There is actually quite some difference in quality.
Hi, I have discovered that, if I connect my dynamo to my light system, the chip controls the output voltage from the dynamo and limits it from maximum 24V to less than 5V, at this voltage, my voltage regulator won't work, means, I can´t charge things when the lights is on. I don't understand how my light system works. If it drains the voltage down to 5V, it might be, taking all the extra energy which my dynamo generates and the light itself doesn't need, away and make it even harder to ride. Or, it could be, it sync with the output from the dynamo and acts as a motor driver and put back the extra energy into the dynamo? Could be, but I don't think so. Because the output is drop down to 5V, otherwise the voltage would be higher. And a interesting fact, my front light works always, but my back light works only when the input to light system is AC current. And if it is at a low speed 3km/h, the blinking between front and back doesn't sync either. Front light twice or more and back light only once. Do you guys have any idea?
Well, Ollie definitely did a better job then Dan or Si ever did with the science glasses gag. That was entertaining, I laughed hard. No offense to Dan or Simon it's still funny when they do it.
How about some more information to understand how much energy the dynamo produces? How long would it take to charge an external battery? How does the amount of electricity produced by the dynamo compared to what you get out of a wall socket? I understand this answer is complicated because it would depend on your speed and in the case of the wall socket the country in which you live.
Do you have a dynamo on your bike? If not, would you get one now? Let us know your thoughts in the comments below 👇
GCN Tech I do and it powers my automatic shifter. As it charges a couple of 18650s I can also charge my phone off it with a little voltage convertor circuit.
yes, and it powers my lights. Simple and efficient. I dont care about drag or weight. Great invention.
GCN Tech It wasn't really made clear in the video but before connecting a dynamo to a battery its important to check if the output is AC or DC. Most dynamos I've come across put out AC so it's essential to use a rectifier between the dynamo and battery.
Ed R you made your own batterypack of 18650s? Which ones? Panasonic ncr?
Sounds like good idea for biking around for weeks
Calvin Pessl Just some old ones from an old laptop battery, I'm using 2 cells in series. Mine really has one purpose which is to power the automatic shifter. The 8.4 volts is perfect for an Arduino and a servo. Left a comment below asking if anyone knows the optimum voltage for such a battery pack.
An AC-DC "converter" is called a rectifier. It's not something anyone needs to know, but when you do know it, you can never help but correct those who aren't aware of it.
On a normal electrical generator the electricity is gathered from two different ring contacts (separated on the axial dimension) with pads that are in continuous contact. The dynamo uses a single ring contact that is cut in two halves (half rings) and pads on the opposite sides of the ring. As the dynamo rotates, the coils will produce alternatively a positive and negative polarization, but as the ring rotates the pads will contact first one then another coil (dynamos work on two coils only).
Disadvantages of dynamos: mechanical complexity, the magnets are fixed so you need to rotate the coils and gather electricity from them (increases electrical and mechanical losses), they need one collector ring for every two poles so most are bipolar, when rotating a bipolar generator you have peaks and troughs in the necessary force (they don't roll smoothly). A magneto can have the magnets on the moving part of the device so no mechanical and electrical losses on the collector part, can be made with multiple "pols" (phases) so the peaks and troughs are much lower, rectifiers are gonna work forever at peak efficiency (unlike mechanical systems with brushes collecting electricity).
Did someone say "Full Bridge Rectifier"??!!
@@JKPieGuy FULL BRIDGE RECTIFIER!!
@@soupgaming5923 ElectroBoom would still find a way to get a shock with these
Growing up an ACDC converter was called a speaker, lol
Magneto is the villain in X-Men, Dynamo is the villain in the Running Man.
I love how Ollie puts on a Midwest American accent when he wants to sound like a scientist. Those of us across the pond typically don an RP British accent when we want to sound smart. Hilarious!
Sooo true
It sounded to me like he was imitating professor Frink from the Simpsons.
Even more disconcerting was the Jimmy Saville impression at the end.
After the way they handled brexit, and the coronavirus, etc, etc I don't think anyone is going to be imitating a brit to sound smart anymore :)
Really - I’m from the Midwest and I didn’t notice the accent you’re referencing.
Informative video, but more to the point, i'm quite impressed with how Ollie has managed to fit in so well with GCN. Chapeau!
You're the best Ollie! Can you also do one where you actually install it etc. up until the point where your phone is actually charging?
Thats a good idea, we'll see what we can do
This would be really cool. The video was good, but I felt we needed to see a dynamo/magneto in use and actually charging something to fully grasp how cool it is.
+1 for that video
www.cyclingabout.com/best-dynamo-hub-bicycle-touring-bikepacking/ everything you want to know :)
Ollie is quickly becoming one of my favorite presenters. Good work.
Ollie is slowly unbecoming one of my least favorite presenters. Good work!
He's in my top 8 for sure.
Shannon Ayres his also becoming my favourite mathematician. 440 grams is nearly four times 96 grams. Got to love the British education system when apparently Ollie has a PhD.
Usually I didn't understand many foreign people videos but you are understandable and I liked your video👌
Dynamos are awesome! I've been using a Shimano Alfine dynamo hub with B&M lights(front and rear) on my commuter bike for almost 2 years and the lights are great to have whenever I want. They are also pretty bright compared to alot of the midrange bike lights I've used in the past.
Boo! What a mundane use-for-everyday setup! Imagine all the grams you are wasting!
I'm joking of course. I have one bike, that has to do it all. So I have fenders, a pannier rack, fixed lights, the works.
Seeing the nerds on GCN discuss losses of half Watts and weight savings of grams makes me chuckle.
Dynamo hubs are totally the way to go. I have only used them with LED lights. I have never tried to charge devices. I have used a vintage Sturmey Archer, a new Sturmey Archer and an SP. They all delivered bright reliable light at night.
This was great help for my physics Igcse electro magnetic induction topic. Thanks for the help GCN
Thank God a nice video about dynamo hub!
Next video is how to service it!
We'll add that to the list!
I know vintage dynohubs are easy to service, despite how scared a lot of people are of them, but I'd imagine modern ones with sealed or press fit components are much less straightforward, and have no better spare parts availability than one from 1936.
and how to charge a power bank from a son hub!?!
Jack Mitchell what dynamo hub you have?
Thanks for the explanations and differenciation between both, especially about the AC and DC
Ollie are perfect for GCN!
Great video! Glad that my bike have a dynamo and it's actually the best thing ever for daily commuters 🙌
Absolutely the best upgrade I have made on my commuting bike. The power is always available and the lights can be permanently attached. Just be sure to get lights with a capacitor/standlight so you aren't left in darkness when you stop at traffic lights.
Nice to see you on GCN Ollie..
Nice info on dynamo hub. Currently running on Shimano dynohubs on some of my bicycles. It just works fine.
Nice AC/DC reference! It's a long way to the top if you wanna K.O.M.
on the highway to hell
Nice review. Used to have one on my bike back in the 70’s to run my lights. May well consider one again after watching this👍🇦🇺
Nice
I have one on my Litespeed and it’s awesome and drag is so negligible I leave the light on permanently. Highly recommend K-Lite headlight specifically built to suit.
Thanks for the video. At the time Sturmey Archer trademarked Dynamo cars also had Dynamos that was in the 1930s. I begged a 1950's 3-speed dyno-hub in order to answer some questions people were asking in some of the vintage and near veteran bike Facebook groups. The losses in a dynamo which is electrically simply a generator are
Copper losses in the case of an AG/FG/GH are 5 ohms which when drawing current (300mA) is 1.5W = 5 x 0.3
Eddy current losses these depend on how thin the laminations, which minimise current circulating in the iron by breaking the circuit that would be made if it were solid mu-metal, the soft iron, conducting fluctuating magnetism to the winding. A mains transformer and good motors have quite a thin, and therefore efficient, compared to a dynamo. I do expect that the dynamo is not particularly good. I am told of one modern hub dynamo that makes the bike much harder to peddle when the bike is ridden at speed when the AC generated is a higher frequency than 50Hz mains. This may be due to this issue?
Magnetising current - the power needed to keep changing the polarity of magnetism - for mu-metal this is very good.
blog.andrew-lohmann.me.uk/2019/07/bicycle-hub-dynamo-maintanance-project.html
But I have a question does a 3W dynamo provide enough power for all the lights and IT. The answer is going to be no but will it be enough for the average person bike lighting and provide enough to top up his phone a bit?
I kept waiting for you to tell me that I could win this wheel, which would have been tremendous, but you didn't, and now I'm sad. I'll tell you what, if you want to make it up to me, you can send me the wheel.
I loved it when you said "reverse the polarity". Now please say "modulate the shield frequency."
The current Doctor only ever says "Destroy the Patriarchy..." :(
Don't have dynamo......yet but after this brilliant video i'm one step closer to get one:-) Very good work one of the best from Ollie brilliant.
I love my hunt dynamo wheelset. The drag is negligible, and it's a nice piece of mind to know that your lights won't run out of batteries.
Oh, and one minor correction: the dynamo hub generates AC current, not DC. This is why the lights tend to flicker at slower speeds. In fact, if you freeze the frame at 3:18 you'll see a neat little sine wave on the flange letting you know that you need an AC to DC converter for your USB devices.
Awesome video breakdown, this really helped me make an informed decision for my next bike tour. Thanks!
When I was a kid I used love my old bottle dynamo(s) I had this awesome front lamp on the right hand fork that would light up tree canopy dark roads in Bedfordshire. My mates had these crappy Ever Ready battery lights that used a pair of AAs that were just no comparison. The last time I used one was around 2000 but was experiencing problems with the contact wheel slipping on the tyre in the wet and without a proper mounting boss on the fork used a hacked solution that utilised a bracket that used the cantilever boss. Just use modern LEDs now but when I spec up a new touring bike, probably a Condor, I'll have one of the Son hubs. As others are saying though it is necessary to add somekind of circuitry to maintain steady current.
I enjoyed nerding out and learning about dynamo hubs! Thanks for the good quality video :)
This is so slay. Helped me a lot 🤟🤟🤟
I have a Son28 dyno hub, hooked up to a Supernova e3 triple heads light and a e3 tail light. I also have a sinewave Revolution usb charger. This setup was expensive but its worth it knowing that I have lights any time I need them, and I can charge a powerbank witch I can then use to charge my phone, ipod, gopro and gps while I'm out touring.
I've got the SON delux with Edelux2 and Sinewave Revolution and a battery pack that allows for pass-through charging. It is expensive but knowing that I can run all night is good piece of mind.
What set up should you recommend with gears like dslr cameras and laptop? Thank you in advance.
Excellent video Ollie, thinking about a dynamo for my Gravel Bike it would be very handy.
Let us know if you get one!
I grew up in Romanian in the 80s. Many people depended on public bus, trains and personal bikes to get around. They had these dynamos back then. My grandfather had one on his bike he rode to work and back.
Very practical devices. Bicycle dynamos have been on the market for a century.
Great video. Lots of info and well presented.
I really hope you're going to do a follow up video to this one. There's a lot of questions and confusion down there !
Please put the derivation of Maxwell's Equations in the description, thanks.
Good video... Ollie is the perfekt reporter and moderator...AND... 2 more Powerbanks in your sattle bag are more heavy than a dynamo in the hub.. (-;
+GCN Tech
@6:35 Not necessarily true. A magneto doesn't always produce ac current, for example an ignition magneto on 2 stroke engines produces a dc pulse.
I have a son dynamo hub on my gravel bike with an edelux light and a Shimano Nexus with a non branded plastic light on my commuter, I love dynamo lights, not worrying about batteries is excellent. I want to upgrade my mountain bikes to dynamo lights too.
Engaging review! Nice presentation and well worth the technical explanation.
Have a dynamo on my commuter, wouldn’t dream of,putting one on my race though
I would not charge even a batterypack with a wheel dynamos without having a circuit that keeps the voltage at a steady USB-standard of voltage and current. The dynamo on the HUNT wheel seems to have 6volt output at 16km/h, so If I assume correctly, it means it will output even more going at 30km/h and therefor can damage the electronics you try to charge.
Andrew N yeah I heard your have to regulate the voltage and current somehow because it can spike during riding. But then can you can charge your phone directly from that voltage regulator? Or do you have to charge your battery pack first then your phone? Because that kinda seems inefficient imo
All yo need is a simple voltage regulator. Here's the video on how to do it. ruclips.net/video/GSzVs7_aW-Y/видео.html&vl=en
Generally the voltage is self regulating to an extent because the efficiency of the generator decays as the speed increases, it's how they generally avoided blowing bulbs going down hills while still having lights going up them. As a result, it doesn't take a lot to get a totally smooth output, you just need to bridge the terminals with a suitable resistor.
Which begs the question: why hasn't a clever dynamo manufacturer built the regulating circuitry right into the hub so that the output could be used directly to charge USB devices? A sort of "iDynamo"?
Paul Flory depending on the circuitry it may not work within a close proximity to the magnetic field that's being radiated from the dynamo and the hub most likely also has a lot more vibrations than the frame of a bike which could add unnecessary wear to the circuitry, especially soldered components on a small PCB.
I thought about going dynamo on my adventure (gravel) bike set up but for all the extra cost and effort it just seemed easier to get a solar rechargeable battery with 25k mAh which lasts 3-4 days. If you intend to cycle through the night or go a very long time in crap weather and no access to electric then I can see why you would usea dynamo.
Do you need a dynamo specific wheel?... so do you generally buy them separately and then take them to you LBS to build???
Could this be used as an alternator on an e bike..?
Sir Do we need to give more Force to run Dynamo hub wheel??????
Good vid man thanks
Very informative
Can you combine a dynamo with the Di2 derailleurs?
Przemyslaw Sliwinski -- di2 is charged through a normal USB connnector, so yes, you'd charge a battery pack first. Then plug battery pack in to di2. Battery on di2 lasts a flipping long time though so unless you're cycling around the world in 80days and don't see a single plug, you shouldn't need to charge it
Thank you - I am considering an Alfine Di2-based setup.
Awesome & Thanks :)
'...that's nearly four times more.' Um, it's actually 4.5 times more than 96g. Great video nonetheless Ollie as been wanting to know about the benefits and drawbacks of dynamo hubs for a while.
Good info! It was nice to actually learn how much drag these things produce in empirical terms.
It will depend on load power, so without electric power meter connected between dynamo and battery pack or charger you will never know how much power is used to charge power bank, because of charging Li-ion batteries for example in non linear process with current much lower at the end, so wthose power ratings on those dynamos whatever it is can be only some kind of capabilities of such things what they can do and how much power you can take from this thing but it can't tell you without electric power measurement how much drag power it uses at the moment ;) It is worth to know basic electronics anyway and do not relay on Yt video like this one because of you can miss many important things while presenters in GCn have sometimes pure understanding how physics works :)
@@szankony6276 "presenters in GCn have sometimes pure understanding how physics works" While Szan Kony seems to have poor understanding how English words work. SCNR ;)
Could you use a dynamo to charge your electronic shifter battery? Or even leave out the battery?
I carry a small solar panel on my rando bag. Works for me, but I also don't have many gadgets other than my cell phone and my Roam. The cell phone I keep off during my ride. I used to ride lots at night but after a couple of spills I shy away from night rides.
thanks but would've liked some info on output and what sort of limitations on the amperage you can pull from these, as well as different models and specs. on to the next vid on these...
Standard requirement for a lighting dynamo is three watts at moderate speeds (.5 Amps at 3 Volts) Most current hub dynamos will easily deliver up to 6 Watts. With special charging circuitry like the dynamo harvester you may squeeze out up to 12 Watts. (At the standard USB 5 Volts in this case.)
6 Watts of drag at how much electrical output power? It depends on the load you're drawing. I can't afford the SON kit so I use the Shimano ones, they're fine as long as you stay away from the "DH-32" model that's nfg.
You can get phone adapters with rectumfryer and surge protector that let you charge from the dynohub without intermediate powerbank, LiPo batteries are pretty efficient but you always incur at least 10-20% loss by storing the energy in a battery and then getting it out again.
You didn't include anything about connectivity, lights, chargers, power banks. I know some basic stuff about electronics and I can tell that no gadget uses 6V. USB standard voltage is at 5 +-0.2V and 3W is close to half power than a basic USB 1A charger. I suggest you do a follow up video on everything about the peripherals of a dynamo.
al kiou the video is more advert than providing information
Many gadgets can easy step down to 5V from 6V, so it is better to have 6V than 5V, because of one need to regulate voltage level to 5V with different tolerances, so having 6V is advantage, because of one do not have to step up to higher voltage before using eg. linear voltage regulator which need slightly higher voltage than 5V to step down easy to 5V.
I'd like to see test where you connect multimeter with small load lets say 1W at see if those wheel dynamos whatever it is called have some step up converters which will help output 6V regardles of cruising speed in soem range lets say between 10km/h to 90km/h ;)
My guess is that you’re too young Ollie to have seen Brains on Thunderbirds when it was first broadcast but thanks for an entertaining impression of Brains.
Hi. Can we have a review for Bicycle Dynamo CHAIN contact generator?
I've got a cheap and nasty bottle dynamo on a city commuting bike. I've noticed that whenever it rains the dynamo doesn't produce enough power for my lights. (I suppose either water is getting underneath the bottle top or possibly the water between the tire and the bottle top is causing the issue) I've also got to cycle up a steep hill and there's always that bit of resistance whenever I use a bottle dynamo.
Would a hub dynamo get around these issues? If so, how is one installed? Do I need to buy a brand new wheel rim?
Hunt (and probably others) sells wheels with a dynamo. You could also buy a dynamo by itself and have it built into a wheel you already own by your LBS. Just make sure they each take the same number of spokes.
You could buy a new idler wheel for you bottle dynamo, or re-face it with grit, to reduce slippage when it's wet.
I have a dynamo "F12W-PRO", it can charge my iPhone directly. At the same time, it can provide the power of the lights.
Too bad no links for all that were mentioned. Are these brushless or brushed in transfer? If these dynamos had enough output, they could help charge a battery on an electric bike to extend range.
Is there a battery in the hub so you charge devices when off the bike? or somehow you use a wire while the wheel is spinning?
Different hubs work differently because of patents and what not, but the classic and class defining Sturmey Archer GH6 uses a 20 pole magnet which bolts into the hub shell and then has a copper wound armature which sits within it and is clamped to the axle by the lock nuts. The wires connect to the armature which is stationary as the magnet spins around it, I imagine that modern ones operate in a similar way.
Wow. Dynamos wheely are the wheel deal!
I saw that someone below mentioned installation and use video. Did you ever make one ? Can I have one on the front and the back ? If you have time, that would be great. I need to figure this out, and instead of me dinging around and messing up, it would be great to just watch a video instead.
Drawbacks for hub dynamos: weight, drag, and......price, low output and maintenance. I believe both SP and SON hubs have to go back to the manufacturer for bearing replacement, which, if you ride a lot of miles, could be every 1-2 years. And the hub has to be removed from the wheel for that.....so then you have to have the wheel rebuilt. And the amount of light you get with a hub dynamo light is pretty sad compared to a battery light system you can put together for $30, as I have. And I can move that battery system to any of my bikes, even though they have different wheel sizes/brake systems. I really want to like dynamo lights, but I just can't get past the hundreds of dollars extra cost for far less performance.
How do you compute the generated power output of dynami
How do you charge your devices on the fly?
My bikepacking bike is a Cannondale 29er hardtail with a Lefty fork so has anyone been able to build a Lefty compatible front wheel with dynamo hub?
Ive seen these in the uk for sale and they usually say 700c x 28 can i fit a 700c x 25mm tyre on one of those
If you stop at traffic do the lights stay on or stop working?
"Dynamos are for charging IT devices, or charging lights. Or driving lights directly!"
Sign of the times, I guess...
Also, complaining about the drag of a switched on dynamo: It's physics, dummy! Also known as the law of energy conservation.
On the longest tour I have ridden up to now I had a 'be on' dynamo harvester charging device (now available from NC-17) that actually extracted up to 12 Watts out of my SON. And if you carry a lot of electronics, as we tend to do these days, you are happy about every single one of these watts.
That's why you don't want the delux version of the SON on a tour. Yes it's a bit lighter, but it also extracts less power. Go with the 28.
ETA: The NC-17 AppCon 3000 unfortunately is not nearly as powerful as the dynamo harvester. They claim that they have optimized for slower speeds (below 15 km/h), which are more common on tour, but frankly, it's not all that more efficient there to warrant the change.
The best charging device today is the Forumslader ( forumslader.de ) If you need high power.
its a bit unethical to extract energy from your son
@@griffin3964 Should I stop having him tread the home trainer to power the TV, yathink?
What I'm curious about is if it is a brushless design or not, which would be WAY superior to anything else out there and much more efficient. I looked at one of Hunt's videos and it showed the guts of one and it does look brushless, hence no commutator. It that is the case, it would actually be an syncronous alternator and use a rectifier internally. That would be slick indeed and be practically maintenance free... except for the bearings.
But somehow, "syncronous rectifer" just doesn't roll off the tongue, does it!?!? It's the antithisis of a sexy name. Yeah, stick to Dynamo.
#askgcntech what about the non friction dynamos? Have you ever used one? Are they any good?
If you don't draw any power, the difference is barely feelable. If you do, that's the price you pay to generate power.
The DC coming from the dynamo will most definitely damage your phone because a Dynamo creates AC. That's why you need to buy a device to convert it to DC (A rectifier) before you charge any device.
Can a dynamo be used on an e-bike to charge a battery? I want to increase the range if my e-bike.
Do I just plug my cable into the spokes? Kind of a half explanation here. Didn't really see a single unit in use on a bike
At 00:30 you see two rectangular pins next to the axle. That where you put the connectors on. A shimano connector looks different and is easier to use.
Is there an easy way to determine how large of a power bank you can charge on a ride of a given distance with a dynamo? Could you charge a spare e-bike battery for a bike-packing companion on an e-bike?
How do you actually plug in your device? Where does the cable go?
At 00:30 you see two rectangular pins left of the axle. That is where you put the connectors on. You still need some sort of charging device, like a bm usb werk, cycle2charge, etc
For what its worth there is big differences between a Magneto and a Dynamo . A Magneto produces AC voltage with permanent magnets and a Dynamo produces DC voltage using a commutator ..
Thanks
Can i use a car charger whit a dynamo to charge my phone or do i need a powerbank first like u said
Also, of course, watts are watts. Assuming that the dynamo is efficient, a dynamo that cause more drag will charge your devices faster, up to the maximum number of watts the battery can accept.
By the way, you forgot the number one reason why bottle dynamos are horrible: Slippage! They might work well in the dry, but once things start getting wet and cold, they will invariably start slipping. So you go to your local bike store or read something on the net about a new miracle dynamo that won't slip, you buy it, and it doesn't slip. Not for the first week or so. Then it's back to square one...
Bonded carbide grit idler wheels don't slip, but they wear the tires more quickly than the common knurled steel idler wheels.
I had a dynamo on my 1968 RSW 16!
The on one my 1977 Raleigh 20 still is.
I tried charging battery pack using dynamo hub, but it goes awfully slow. Not recommended. Charging iPhone or Wahoo ELEMNT directly from it, works perfectly.
I like the Withnail and I reference .
I did wonder if anyone would notice!
The drag is actually much greater than the amount of watts they produce, that hub probably creates 10.5 watts of drag when producing 6 watts of energy. They are no where near 100% efficient.
A fantastic video for people who already know everything suggested by the title. For others wanting to learn, not so great.... no description of exactly what it is to a cyclist, no view of how it connects to the bike or how it's actually used in practice. It's said that you can use them to charge equipment like phones and computers and heated blankets(?), but not even the slightest hint at the charging capacity (e.g. a 10-minute ride will charge your heated blanket for a toasty night's sleep?).
Not up to GCN standards.
gcn has been confused for a while now
How bright of a front light can you power?
They get pretty bright with LED technology, modern dynamos will output 6V at 3W (0.5A) AC, which is plenty. Even with classic dynohubs, which were killed by the 1985 Road Vehicle Lighting Regulations, the light output using leds is easily comparable to battery powered lights. The things to watch are standlights and rectification, which some lamps will have built in but which can be annoying if missing, dynamos don't keep the lights on at traffic lights by themselves, and without a rectifier, all leds will strobe.
They get pretty bright with LED technology, modern dynamos will output 6V at 3W (0.5A) AC, which is plenty. Even with classic dynohubs, which were killed by the 1985 Road Vehicle Lighting Regulations, the light output using leds is easily comparable to battery powered lights. The things to watch are standlights and rectification, which some lamps will have built in but which can be annoying if missing, dynamos don't keep the lights on at traffic lights by themselves, and without a rectifier, all leds will strobe.
Dt swiss hub in centrelock is 113g 👍😉
thank you
If someone is intrested, there are some nice information on some dynamos on: fahrradzukunft.de/14/neue-nabendynamos-im-test/
Its german but you should be able to comprehend the graphs in the lower part of the article:
(1): mechanical input lights off
(2): electric output on 12 Ω
(3): mechanical input on 12 Ω
(4): electric output on 24 Ω
(5): mechanical input on 24 Ω
There is actually quite some difference in quality.
Nice I won't too dynamo hub bkie sir how can't order
I thought u were gonna talk about Tesla when glasses went on 😂🤙🏽
Hi, I have discovered that, if I connect my dynamo to my light system, the chip controls the output voltage from the dynamo and limits it from maximum 24V to less than 5V, at this voltage, my voltage regulator won't work, means, I can´t charge things when the lights is on.
I don't understand how my light system works. If it drains the voltage down to 5V, it might be, taking all the extra energy which my dynamo generates and the light itself doesn't need, away and make it even harder to ride.
Or, it could be, it sync with the output from the dynamo and acts as a motor driver and put back the extra energy into the dynamo? Could be, but I don't think so. Because the output is drop down to 5V, otherwise the voltage would be higher.
And a interesting fact, my front light works always, but my back light works only when the input to light system is AC current. And if it is at a low speed 3km/h, the blinking between front and back doesn't sync either. Front light twice or more and back light only once.
Do you guys have any idea?
Well, Ollie definitely did a better job then Dan or Si ever did with the science glasses gag. That was entertaining, I laughed hard. No offense to Dan or Simon it's still funny when they do it.
You didnt actually show how it works, like is it a cable that plugs in whilst you're riding?
Every extra Watt of drag is because an extra Watt of power from the dynamo is being used by a gadget.
Ollie, is there really such a thing as a chargeable electric blanket?! That would be a tingly sleep....
Dynamos are great on commuters or tourers. A dynamo wheel turns a bike into a properly practical mode of transport.
I use a SON28 with a sinewave revolution,just connect anything with a USB socket to the sinewave and Bob's your uncle
How about some more information to understand how much energy the dynamo produces? How long would it take to charge an external battery? How does the amount of electricity produced by the dynamo compared to what you get out of a wall socket? I understand this answer is complicated because it would depend on your speed and in the case of the wall socket the country in which you live.