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.

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.

I was surprised, but a lot of the newer ones are really getting up there in wattage and down in weight. Omnicharge has one for $75 that is 20W and weighs 500g. I had wanted to test them so this conversation got me to order one. I’ll let you know how it works. The last time I looked at this, you could pretty much get 7W for that weight.

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.

I tried a smaller solar panel a couple years ago on a kayak trip, trip was two weeks with no access to anything to plug into. And a dynohub on a kayak trip, .. that ain't going to happen. I decided not bringing solar again. If your new panel is that great, I might re-consider.

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.

https://cimg5.ibsrv.net/gimg/bikefor...cbcc766376.jpg

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.

https://cimg2.ibsrv.net/gimg/bikefor...6520c407be.jpg

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:

https://cimg2.ibsrv.net/gimg/bikefor...fc4155077b.jpg

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.

+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.

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.

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)

This guy claims to have a very efficient USB converter, and is also working on a StVZO-compatible headlight with built-in USB converter.

If I was with TSA, I do not think anyone could talk me into believing that a PVC pipe full of electronics is that harmless.

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

The Cycle2charge website claims about 4.8 watts at 20km/hour, that is pretty close to the Forumslader output.
http://www.cycle2charge.de/images/Bi...ich-eng_V3.JPG

Looks interesting. But not cheap either. but the price is probably justified.

That is pretty good and the pricing is good. i wonder why fahrradzukunft never tested this one, as it is from germany. Fahrradzukunft got a sample of the new pedalcell system, i am looking forward to that testing, maybe they then include some other untested systems like the cycle2charge.

I am one of the people who's Luxos U has failed. When I got it, it seemed like a good deal because it was slightly less than the cost of a good dynamo light + a separate USB charger. But then the USB charger failed, and I had to have it replaced. Then the replacement's USB charger failed, then the handlebar button failed entirely, so the light could only be changed using the button on the light itself. Not a terrible tragedy, but that button is kind of tricky and only works with the wheel spinning. Since it was mounted where I couldn't reach it when riding, if I ever turned it off and wanted to turn it on, I had to lift up the front of my bike, get the wheel spinning, and cycle through options using the button until the light came back on. Naturally I generally left the light on. Every so often, though, someone would notice that my light was on and would turn it off for me, thinking that I was going to run out of battery power. It also developed a weird quirk where it would continue to output a small amount of light long after the stand-light had turned off. And by "long after" I mean days. I removed the light from the bike, left it on my workbench for days, and it was still emitting a faint light. Weird. Then one of the tail light contacts rusted off. I had to wire my tail light separately, which wasn't terrible, since I really wasn't able to turn the light off anyway, so running the tail light through the headlight didn't give me any more control. Still, at that point I decided to replace the light. This time I got two devices: a light and a USB charger. I figure if one of the two items fail, I will still have one, functional component. The other benefit I'm realizing is that I have more than one bike, and I'd like to get dynamo hubs/lights for more than just my main bike. I don't want to be moving one light between multiple bikes all the time, so probably every bike will have it's own dynamo light. But USB charging is something I only need occasionally, so I don't mind sharing one charging device between bikes. Much cheaper than buying 3 Luxos Us.

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.

I think I get a tiny bit more power out of the Sinewave Revolution than I get out of my Luxos U which is on a different bike.

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.

I will be checking the Sinewave before hand. i have already set it up to be wired into my hub and have verified that a charge is detected while riding, but I haven't actually charged anything. The charge was too inconsistent for my phone, which was also the case for the Luxos U. The on-and-off of the phone meant that it still lost power over the course of a ride, although that's on my stop-and-go, urban commute. Very possibly it would work better on an actual tour where I didn't have to stop for traffic signals every few minutes. Generally, though, I have worked around this by having it charge a battery that I then used to charge the phone when the day's riding was done.

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.

You want the 80 lux Cyo Premium which will run in parallel with the USB Werk. I use a Schmidt Edelux II, although the Cyo Premium offers the same optics for much less money.

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.

I have a USB Werk. A small cache battery means I don't get many external power disconnected messages from my Garmin. Apart from that, other options may be better with more output at lower speed.

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

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.

They're both replaceable, and the left cone is the same as the right. You can also buy the rotor as an assembly including the left cone.

https://matt.signorini.id.au/?p=114

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.

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.

For you to be correct, then manufacturers must be de-rating their specs by giant margins. That’s not a bet I’d make for the cost of a dynamo.

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.

At this article:
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.

I think you're not in the target market for these sorts of devices, then.

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.

Are you saying this device draws more power as input voltage increases? That's pretty smart.

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...