Hub dynamo to USB charger
#26
Senior Member
The drag is not that bad. It's so little that you can't feel it. But the power output is low. It's 3W (at 6V) nominally, not 6W. They could make dynamos that put out more, but then the drag would be intolerable. So they're great for powering lights, but that's because lights do great with 2 or 3 watts. But it's not enough or cost-justified for charging except in a very few cases. And even if it's good for charging, you should still have at least one spare external battery.
I run dynamo lights, and they work great for me. I run them day or night, so there is no charging available from the system.
I run dynamo lights, and they work great for me. I run them day or night, so there is no charging available from the system.
They work well for lights only. Dynamos are at the limit of their capability for that since there isn’t much left over for charging They really don’t work all that well if you have even modest battery needs by today’s standards. There is no real room left to add more charging capability in the design of dynamos because it’s going to eat into your rolling resistance pretty significantly if charging were to go to, say, 20W which would be reasonable but that would likely require 30-35W at the cranks (which would be a problem). 20W would be pretty reasonable and would be enough to support a single 5V/1A plus a single 5V/2.4A USB ports.
I see dynamos as useful if you’re completely off grid and have no access to an outlet. I also see them as being overtaken by solar panels pretty quickly.
#27
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Really, solar panels are useful? I read the ratings from time to time, and it seems that the space required and the small output don't justify the expense. And you pretty much need ideal conditions, and it isn't always easy to drape them on your bike over your baggage. But I'd be glad to know I'm wrong. I haven't toured much recently, but I suspect batteries seem like the best bridge between power outlets. It also pays to reduce power consumption as much as possible.
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#28
Senior Member
Really, solar panels are useful? I read the ratings from time to time, and it seems that the space required and the small output don't justify the expense. And you pretty much need ideal conditions, and it isn't always easy to drape them on your bike over your baggage. But I'd be glad to know I'm wrong. I haven't toured much recently, but I suspect batteries seem like the best bridge between power outlets. It also pays to reduce power consumption as much as possible.
With the solar panels, I think it’s best to have a battery that charges at the voltage output of the panel instead through the USB interface that they all have that is going to drive the efficiency down.
#29
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But, I would prefer a USB port. There are smart battery chargers that are designed to shut off the charge when the battery is charged. I have a couple USB powered AA/AAA chargers and a couple Li Ion chargers. I would rather have a charger that has some smarts in it.
In the photo I have two Eneloop USB powered AA NiMH chargers that can handle two AA batteries, they are the white things hanging from the outlet, and one Li Ion charger that looks like a clamp that is holding one of my camera batteries.
And in this photo, there are four AAA NiMH batteries in the black box which I think is called a Power Chimp, the green light means that that battery is charged, the other three are still charging.
The black box opened up, disregard the white rectangle, that is a piece of foam that I put in the box when riding to keep the AAA batteries from rattling, the box is sized for AA or AAA batteries:
Last edited by Tourist in MSN; 02-14-20 at 04:53 PM.
#30
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The problem with solar panels is (1) they have to be fairly large for anything over 20W and (2) you need fairly ideal conditions to get to full power out of the solar panel, if it’s cloudy, raining, or heavy trees you may not get full power (or any power). Also you have to spend time getting the position just right so you get the maximum power and then the sun moves around on you. Strapping them to the bike and hoping for the best won’t produce good results.
I have a small 7w solar panel that is the size of a small tablet, but don’t use it that much. I use a SON dynamo with Edulux 2 dynamo lighting and a USB charger. It’s true that 3W only gives you 5V/600mA but this is enough to charge an in-line battery and keep the Garmin, iPhone and some other small devices such as backup battery lights charged for rides 300km or longer. Loss of 3W comes out to increasing the riding time about 10minutes per 100km for me at my long distance pace.
I have a small 7w solar panel that is the size of a small tablet, but don’t use it that much. I use a SON dynamo with Edulux 2 dynamo lighting and a USB charger. It’s true that 3W only gives you 5V/600mA but this is enough to charge an in-line battery and keep the Garmin, iPhone and some other small devices such as backup battery lights charged for rides 300km or longer. Loss of 3W comes out to increasing the riding time about 10minutes per 100km for me at my long distance pace.
#31
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+1 for the Sinewave Revolution. I have two of the Reactors (which is a light and revolution in one) and it works perfectly. The SP hubs are really good for the money, and you can only really feel the drag if you are rolling it with your hand.
#32
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Bugger, you made me disappear down the rabbit hole that is German hub dynamo websites... Looks like a lot of manufacturers have got on the band wagon of impedance matching to maximise output at all speeds. Still like my Forumslader though because it does everything because it has an internal battery. I have the big battery version with the USB Loader cable, so I can use it as a standard USB power pack and charge from AC if needed. I put it in a PVC tube the size of an old school bike pump and it clips into pump clips on my downtube. I disconnect it and take it into the tent at night. The only slight downside is it looks like a bomb to Airport security, what with it being slightly home made, having a push button and flashing lights. Usually gives them a laugh when I explain it though.
#33
Senior Member
Bugger, you made me disappear down the rabbit hole that is German hub dynamo websites... Looks like a lot of manufacturers have got on the band wagon of impedance matching to maximise output at all speeds. Still like my Forumslader though because it does everything because it has an internal battery.
#34
mosquito rancher
#35
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Bugger, you made me disappear down the rabbit hole that is German hub dynamo websites... Looks like a lot of manufacturers have got on the band wagon of impedance matching to maximise output at all speeds. Still like my Forumslader though because it does everything because it has an internal battery. I have the big battery version with the USB Loader cable, so I can use it as a standard USB power pack and charge from AC if needed. I put it in a PVC tube the size of an old school bike pump and it clips into pump clips on my downtube. I disconnect it and take it into the tent at night. The only slight downside is it looks like a bomb to Airport security, what with it being slightly home made, having a push button and flashing lights. Usually gives them a laugh when I explain it though.
I have had good luck with my Sinewave Revolution, but when I saw the output claimed by the Cycle2Charge, I thought about ordering one. That is until I saw a 30 Euro shipping charge to USA, then I rapidly lost interest. If my Sinewave died, I would probably give the Cycle2charge a try as the price with shipping is competitive with another Sinewave, but I do not need another charger that much. And the Sinewave waterproofing is exceptional, I have no clue how well waterproofed the Cycle2charge is.
Cycle2Charge
Be assured, in that rabbit hole (i've disappeared down there also more than once) you'll find that the forumlader is still one of the best energy harvesting systems available, there is only one that is at speeds below 20 km/h a tiny bit better (tout terrain the plug 5 plus)
https://www.cycle2charge.de/images/Bi...ich-eng_V3.JPG
#36
Senior Member
This guy claims to have a very efficient USB converter, and is also working on a StVZO-compatible headlight with built-in USB converter.
The Cycle2charge website claims about 4.8 watts at 20km/hour, that is pretty close to the Forumslader output.
https://www.cycle2charge.de/images/Bi...ich-eng_V3.JPG
https://www.cycle2charge.de/images/Bi...ich-eng_V3.JPG
#37
Senior Member
Unterhausen raises a good point, some lights including the Luxos U have had a reputation for water ingress or other failures. I think that most of the water problems with the Luxos U were solved after they re-designed the remote switch several years ago, but you still occasionally hear of failures. Apparently the four electrical contacts in the rear are not waterproofed in any way. I do not tour with my Luxos U, I mostly use it for around home riding and I usually do not ride on rainy days by choice.
I do ride in all weather. The bike is my main transportation, so I don't get to set it aside on rainy days. I imagine most of my problems are a result of water damage, although my 2nd light, at least, should have been the version that was better protected against water damage.
So, for my part, I don't recommend the Luxos U if you're going to ride in the rain. Too expensive to risk, and it will be cheaper to replace the two, individual components in the future if either the light or the USB charger dies.
On solar panels: I do have a 21 watt, 4 panel, foldable solar panel that has helped me keep things charged to a certain extent. It works best if the sun, obviously. I've had good luck at music festivals where I can sit in the sun for hours at a time. I've had decent results on sunny, or even overcast, days where I can drape it over my handlebars and ride all day down open roads. I've had poor luck when riding wooded trails on days when rain is in the forecast. When my Luxos U had not been replaced, I used the solar panel and a portable battery to keep my phone charged when riding down the C&O canal trail. Intermittent rain and almost constant shade meant that the solar panel was not super efficient, but it eaked out enough juice to keep from needing to plug in for about 200 miles/4 days. When I got DC, though, I was running low on juice. It's worth it to me, but it's not as reliable as a dynamo if you know that you will be rolling for a good chunk of the day.
I have not yet tested out the Sinewave that replaced the USB part of my Luxos U, but I have a five day trip planned this spring where I will have no access to a plug, so I hope to put it through its paces then.
#38
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I always check out all of my equipment before I pack up my gear for a tour. It is rare when I am surprised by something that does not function, but there have been a few times that I was glad I set up a tent to check it first or checked my stove to make sure it works well while still at home, etc. Given the bad luck you had with your Luxos U chargers, you might want to hook up the Sinewave and make sure it puts power into your powerbank ok well before your tour starts,
If the battery pack in the Luxos U is still there, that might put a small drain on your hub even when the light is turned off. That might be something to check before your tour starts. It is my understanding that the battery pack supplies the standlight on the light, thus I assume it is still part of your light.
If you are curious about my setup for electrics for touring, I described that in detail on another forum at this link:
Electrics that I use for bike touring - what works for me.
#39
Senior Member
Given the bad luck you had with your Luxos U chargers, you might want to hook up the Sinewave and make sure it puts power into your powerbank ok well before your tour starts,
If the battery pack in the Luxos U is still there, that might put a small drain on your hub even when the light is turned off. That might be something to check before your tour starts. It is my understanding that the battery pack supplies the standlight on the light, thus I assume it is still part of your light.
If the battery pack in the Luxos U is still there, that might put a small drain on your hub even when the light is turned off. That might be something to check before your tour starts. It is my understanding that the battery pack supplies the standlight on the light, thus I assume it is still part of your light.
The Luxos U is off the bike for the time being. I have switched to a Cyo T, which has the advantage of fairly straightforward switch, so I can turn it off and not divert any energy from the Sinewave. When I'm not charging anything, I just leave it on in the daytime running light mode. I don't really notice any change in the friction of the hub when the light is off vs. on. At least not enough to ever bother turning the light off.
The Luxos U may have continued to draw a little on the hub to replenish its cache battery. I don't know, but, like the Cyo, I usually left it on, so it didn't really matter. What surprised me is that the cache battery seemed to continue to supply a small amount of power to the lights for days at a time, even when not connected to the hub, and it also surprised me that the light didn't fully turn off when it passed its "standlight" time, although I think that was more damage to the light, because I think when the light was new, it did not have quality of continuing to emit a tiny bit of light for days on end when not in use.
#40
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Last year my wife convinced me we didn't need a hub dyno and lighting and money was tight with the camping gear we already bought and on the first night we got lost in the dark. While it was nice to say I was right it wasn't convenient so this year's tour is being prepped starting with a pair of hub dynos for the adults and usb rechargeable lights for the kids. I'm looking at a shutter precision hub as it seems to get decent reviews for a good price along with a Busch and Muller 40lux light.
The IQX reportedly has problems running in parallel with a USB Werk.
The Luxos U has a built-in USB port, but turns it off when the light comes on. Some people also report water ingress issues.
During the day I wouldn't mind the extra drag to charge things and I'm looking at this
https://www.bike24.com/1.php?content=8;product=38306 Busch and Muller USB Werk 361bw
to charge the two battery packs I have which will keep phones and USB lights topped up while riding. Will this be sufficent and is it decent or should I be looking at something more?
Secondary question. Are dynamo hubs solid enough to build into the existing wheels and riding with full time or should I build them into seperate wheels for touring use only.
https://www.bike24.com/1.php?content=8;product=38306 Busch and Muller USB Werk 361bw
to charge the two battery packs I have which will keep phones and USB lights topped up while riding. Will this be sufficent and is it decent or should I be looking at something more?
Secondary question. Are dynamo hubs solid enough to build into the existing wheels and riding with full time or should I build them into seperate wheels for touring use only.
It's enough to charge my Garmin Edge 800 while in use, so I finish rides with more battery life remaining than I start.
It's not enough to maintain a charge on my Samsung Galaxy S5, unless I switch that into low power mode with no apps running and a dim black and white screen.
Dynamo hubs are plenty strong - front wheels with 100mm OLD axles have a more than ample bracing angle.
The issue is bearing replacement - Schmidt and Shutter Precision hubs require disassembling wheels to replace bearings.
Schmidt claims 50,000 km life. Shutter Precision claims 10,000 - 20,000 which may be one season. Reports of lower bearing life from Shutter Precision hubs aren't uncommon - https://www.bikeforums.net/electroni...placement.html.
Shimano dynamo hubs allow bearing replacement without wheel disassembly. I'd have bought one if I was unwilling to pay for a SON28.
https://matt.signorini.id.au/?p=114
Last edited by Drew Eckhardt; 02-18-20 at 05:18 PM.
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#41
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I attached the schematic for a Shimano hub I have on one of my bikes.
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#42
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The paperwork that came with my Luxos U said that the USB port would still provide power with the light on, but that it was limited to less than 100 milliamps. So, you were close to right, as 100 milliamps from a USB port is only a half watt.
The exploded diagrams that I have seen for Shimano dynohubs only have user replaceable bearings on one side of teh hub, not both sides.
I attached the schematic for a Shimano hub I have on one of my bikes.
The exploded diagrams that I have seen for Shimano dynohubs only have user replaceable bearings on one side of teh hub, not both sides.
I attached the schematic for a Shimano hub I have on one of my bikes.
https://matt.signorini.id.au/?p=114
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#43
Senior Member
I've had my dynohub system since about 2012 if memory serves.
I use a Son28, Edelux 1 headlight and standard E-werk and seperate cache battery.
Apart from replacing the cache battery every three or so years, its been trouble free with the only maintenance being a yearly inspection of the various terminals inspection and clean.
I'd point out that the Usb-werk has an internal battery that I wonder how you replace when it goes kaput.
Locally in Australia I've met 4 riders who've all had trouble with the Luxos headlight and read of more in the various forums I read, so I'd suggest wariness.
I look upon my system as a fit and forget for the most part and after some experimentation I now tend to charge a storage battery which I then use to charge my various devices.
I have a Garmin watch, Edge 1030 with external battery and Petzl headlight torch that I can keep charged on tour as well as an iPhone.
I've been so happy with my system that I've mirror'd said system on my Extrawheel bike trailer.
Edit: I've just remembered that my E-werk is a bit older than I stated due to it coming off my previous bike.
The dynohub though is the newer kit due to my Ogre having disk breaks which the Moulton not having.
I'd foolishly skimped on a non disk hub not considering that I might upgrade the bike.
The E-werks longevity has been great and I'm very pleased with my investment.
I use a Son28, Edelux 1 headlight and standard E-werk and seperate cache battery.
Apart from replacing the cache battery every three or so years, its been trouble free with the only maintenance being a yearly inspection of the various terminals inspection and clean.
I'd point out that the Usb-werk has an internal battery that I wonder how you replace when it goes kaput.
Locally in Australia I've met 4 riders who've all had trouble with the Luxos headlight and read of more in the various forums I read, so I'd suggest wariness.
I look upon my system as a fit and forget for the most part and after some experimentation I now tend to charge a storage battery which I then use to charge my various devices.
I have a Garmin watch, Edge 1030 with external battery and Petzl headlight torch that I can keep charged on tour as well as an iPhone.
I've been so happy with my system that I've mirror'd said system on my Extrawheel bike trailer.
Edit: I've just remembered that my E-werk is a bit older than I stated due to it coming off my previous bike.
The dynohub though is the newer kit due to my Ogre having disk breaks which the Moulton not having.
I'd foolishly skimped on a non disk hub not considering that I might upgrade the bike.
The E-werks longevity has been great and I'm very pleased with my investment.
Last edited by rifraf; 02-24-20 at 09:49 PM.
#44
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I’d agree with that.
They work well for lights only. Dynamos are at the limit of their capability for that since there isn’t much left over for charging They really don’t work all that well if you have even modest battery needs by today’s standards. There is no real room left to add more charging capability in the design of dynamos because it’s going to eat into your rolling resistance pretty significantly if charging were to go to, say, 20W which would be reasonable but that would likely require 30-35W at the cranks (which would be a problem). 20W would be pretty reasonable and would be enough to support a single 5V/1A plus a single 5V/2.4A USB ports.
I see dynamos as useful if you’re completely off grid and have no access to an outlet. I also see them as being overtaken by solar panels pretty quickly.
They work well for lights only. Dynamos are at the limit of their capability for that since there isn’t much left over for charging They really don’t work all that well if you have even modest battery needs by today’s standards. There is no real room left to add more charging capability in the design of dynamos because it’s going to eat into your rolling resistance pretty significantly if charging were to go to, say, 20W which would be reasonable but that would likely require 30-35W at the cranks (which would be a problem). 20W would be pretty reasonable and would be enough to support a single 5V/1A plus a single 5V/2.4A USB ports.
I see dynamos as useful if you’re completely off grid and have no access to an outlet. I also see them as being overtaken by solar panels pretty quickly.
The efficiency of conversion for most dynamo to USB chargers is now in the mid to high 90s percentage wise. So even if you did want to extract 20W it's not going to take 30-35W watts at the crank.
But 10W is what you'll get from a dyno hub at touring speeds, that's 2A. Over a days riding, if you have that going into a battery it's plenty to keep a phone going and have spare for other things. Over a 6 hour day of riding you'll get around 45-50WH into a battery and/or device. I can't imagine why you'd need 120WH a day when you're travelling.
Solar panels are pretty well useless touring unless you're in a desert or Antarctica because you're often in shade or not riding in the right orientation. Having once carried a fairly decent sized one it was ineffective for the room it took up. Also, the guys who we watched getting their panel, battery and gear stolen when they had to put it in a sunny spot slightly away from their campsite ( because you know, trees) probably don't think solar is such a good idea any more. By the time they jumped up to chase the homeless dude running off with their gear, he had way too much of a head start.
#45
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Just so you know, pretty well everything you've said here is not well informed.
The efficiency of conversion for most dynamo to USB chargers is now in the mid to high 90s percentage wise. So even if you did want to extract 20W it's not going to take 30-35W watts at the crank.
But 10W is what you'll get from a dyno hub at touring speeds, that's 2A. Over a days riding, if you have that going into a battery it's plenty to keep a phone going and have spare for other things. Over a 6 hour day of riding you'll get around 45-50WH into a battery and/or device. I can't imagine why you'd need 120WH a day when you're travelling.
Solar panels are pretty well useless touring unless you're in a desert or Antarctica because you're often in shade or not riding in the right orientation. Having once carried a fairly decent sized one it was ineffective for the room it took up. Also, the guys who we watched getting their panel, battery and gear stolen when they had to put it in a sunny spot slightly away from their campsite ( because you know, trees) probably don't think solar is such a good idea any more. By the time they jumped up to chase the homeless dude running off with their gear, he had way too much of a head start.
The efficiency of conversion for most dynamo to USB chargers is now in the mid to high 90s percentage wise. So even if you did want to extract 20W it's not going to take 30-35W watts at the crank.
But 10W is what you'll get from a dyno hub at touring speeds, that's 2A. Over a days riding, if you have that going into a battery it's plenty to keep a phone going and have spare for other things. Over a 6 hour day of riding you'll get around 45-50WH into a battery and/or device. I can't imagine why you'd need 120WH a day when you're travelling.
Solar panels are pretty well useless touring unless you're in a desert or Antarctica because you're often in shade or not riding in the right orientation. Having once carried a fairly decent sized one it was ineffective for the room it took up. Also, the guys who we watched getting their panel, battery and gear stolen when they had to put it in a sunny spot slightly away from their campsite ( because you know, trees) probably don't think solar is such a good idea any more. By the time they jumped up to chase the homeless dude running off with their gear, he had way too much of a head start.
I don’t intend on cycling 6 hours a day for starters. I also have power needs that would put 50WH at the very bottom of acceptable for me. So, a dynamo simply won’t work even if we presume the optimistic power conversion efficiency, output and riding time that you claim is correct.
I also agree that I wouldn’t use a solar panel unless I wanted to be only off grid. But, newer solar panels are more highly efficient and the efficiency is going up fairly quickly. I have a 20W panel that cost $75 and I’m going to be fully testing that next week and then when the sun is higher later in the year.
Otherwise, with the appropriate battery and charger (USB-C PD charger with one of the newer batteries that charges at a high USB-C PD input), you can charge that much or more in a very short time. I have a battery that charges at 30W and is, for example, 34Wh in capacity. Newer batteries are coming out that charge yet faster and the the newer GaN chargers are tiny and light for the power output.
My strategy is to look for outlets and charge the appropriate size battery with a small high power USB-C charger since I’ll be in settled areas. The dynamo set up is expensive and marginal in it’s power output (even using your numbers) and won’t work for either the power needs or the tours I’m planning.
#46
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Just so you know, pretty well everything you've said here is not well informed.
The efficiency of conversion for most dynamo to USB chargers is now in the mid to high 90s percentage wise. So even if you did want to extract 20W it's not going to take 30-35W watts at the crank.....
The efficiency of conversion for most dynamo to USB chargers is now in the mid to high 90s percentage wise. So even if you did want to extract 20W it's not going to take 30-35W watts at the crank.....
https://www.cyclinguk.org/sites/defa...ub-dynamos.pdf
on the third page there are two graphs, one for drag and one for electrical output. When you compare drag and output you can see that there is a lot of inefficiency in the hubs.
But it is my understanding that the chargers that convert the AC current into USB 5v DC have the high efficiencies you cite.
My point is that if you wanted 20 watts of power, you might need 30 to 35 watts at the crank due to the hub inefficiencies.
That said, nobody is going to want to pedal that hard, I am content with the output from my SP hub. If someone feels a need for 20 watts, it is their choice if they desire that much electronic stuff, I don't want that much stuff.
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It is easily possible to get more than the rated output out of a dynamo hub. Dynamo hubs are constant current devices that produce AC over an increasing voltage range as speed increases. By matching the load to the output voltage using capacitors and resistors the output can be much greater than the rated output. As an example the Forumslader has 5 stage load matching, which is switched by a microprocessor, plus a voltage booster at low speeds to maximise output. I suspect some of the more recent chargers have the same thing, given their high outputs.
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It is easily possible to get more than the rated output out of a dynamo hub. Dynamo hubs are constant current devices that produce AC over an increasing voltage range as speed increases. By matching the load to the output voltage using capacitors and resistors the output can be much greater than the rated output. As an example the Forumslader has 5 stage load matching, which is switched by a microprocessor, plus a voltage booster at low speeds to maximise output. I suspect some of the more recent chargers have the same thing, given their high outputs.
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Tom Reingold, tom@noglider.com
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Sort of, it actually changes the characteristics of the dynamo output,by varying things like the magnetic saturation of the core. So it's the output voltage of the dynamo that is being changed. Power can't be created out of nowhere. Dynamos are constant current, usually around 500mA. Dynamo lights are set up so their impedance limits voltage from the hub to around 6V, 6V x 0.5A = 3W. It's why in the old days with incandescent globes it was a bad thing if your tail light blew. That lowered the impedance so the output voltage climbed, and then the headlight bulb blew as well. Manufacturers also set up the system so the maximum power output is quite low in the speed rangeso the lights worked when you were riding slowly, since the amperage is constant they did this by making the hub produce 6V at low revs and effectively putting the brakes on the voltage higher than this. This is a big source of the "inefficiency" mentioned in other posts. That extra voltage (power) goes somewhere as heat. People smarter than me realised you could take advantage of this extra available voltage to increase power output. Because the dynamo output is not linear though, because it's a magnetic system and all sorts of things like induced eddy currents are involved, it needs a staged way of tapping into this extra available power, but the upshot is you can manipulate the hub output to just below the maximum it can produce at various speeds and that is more than 3W and in my hubs up to 10W. This will increase the efficiency of the hub output compared to running a light. It's not possible to go higher than this because that's all the hub can produce, but if somebody was to come out with a bigger hub...
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