Help! Dynamo newbie here!

I know my mechanical stuff, and I know my battery-powered lights, but when it comes to stuff that connects to dyna-hubs and external chargers, I'm at a bit of a loss.

I've been charged with writing up a short Q&A session for some dynohub accessories...except that I don't know much about dynohubs. (I'm very knowledgeable about everything else they wanted me to write about, though.) All I know are the two biggest brands are SON and the Shimano Nexus series. I'm still doing research to see if lights and battery chargers are interchangeable between the two brands, except that aside from reading their corporate websites and product pages, I'm not sure where to start for things I really want to know, like "are there compatibility issues, and what makes one brand incompatible with the other?"

I can probably play it safe sticking to just these two companies, as the company I'm writing for only has hub kits for Shimano and SON. However, it got me to wondering what other dynamo hub brands are out there - like SRAM, Suntour, and maybe Sturmey-Archer - and if I can actually say that those brands might be compatible with either Shimno and SON. Or are Shimano and SON dominating the dyna-hub market to the point that considering other brands isn't even a concern?

Any help would be appreciated.

Shutter Precision dyno hubs are becoming popular because of low price and high efficiency. I've got a PD-8 and it works great. This is my first dyno hub so I have nothing to compare to but I plug it in and start riding and it powers my light. What else could you want?

I've not come across any compatibility issues. I think all dynamo lights will work with any dyno hub. The hubs themselves are designed for a certain diameter rim.

Almost all dynamo hubs produce the same power, 6v, 3w, .5a, so they are all compatible with the lights that are also almost all to the same spec. The spec itself is the German StVZO (or is it StZVO?). The other brands to consider are SRAM, Sanyo, S-A, and Shutter Precision as already mentioned. There are some dynamos that don't produce to this spec but they aren't taken seriously. As far as rim size, there are some that are meant to be used with 20" rims for folding bikes, otherwise 26, 27 or 700c are all compatible.

As far as the brands, only Schmidt seems to make both dynamos and lights.

There really isn't a lot of info on these things, but there are a few pages. The google and siri know everything.

Traditional dynamo hub lighting assumes a 3.0 watt, 6 volt system with a 2.4 watt headlight and a .6 watt taillight. Generally speaking, any light combination designed for a 3.0 watt 6 volt system will work with any hub designed to output 3.0 watts at 6 volts. This is the standard, but it is not 100 percent. The Shutter Precison SV-8 is designed to only output 2.4 watts, for example. The lower output would produce less drag, and might be fine to power lights, but would impact charging. Also, at least one 12 volt (sidewall dynamo) system exists, and those lights wouldn't work with a 6 volt hub.

Not all headlights and taillights are compatible with each other though. The B & M Luxos U, for example, a very advanced light with integrated USB charging capabilities, isn't compatible with all taillights. Supernova headlights and taillights work together differently than other brands, and so they shouldn't be swapped around with other brands.

You can find quite a bit more info on dynamo lighting on the Peter White Cycles page. Sheldon Brown had written some good stuff which might be worth reading for foundation knowledge, but there have been advancements since his passing.

This is no big deal, but if you're writing up something for a presentation, "Dynohub" is a specific product name trademarked by Sturmey-Archer. However, the word is commonly used for any similar hub (the way Kleenex, Band-Aid and Xerox are used generically). The pedantic will delight in informing you these hubs are alternators rather than dynamos (rolls eyes).

Shimano offers a series of lamps for generator hubs. I've never seen one on any bike that wasn't a Shimano display machine at an industry show, and I'm unsure they're still marketed in N.A.

OP, you might throw in a short line that you're only talking about the modern generator hubs of the last decade or so. Vintage Dynohubs produce different voltages and/or wattages than today's offerings.

Shimano has some low power dynohubs that might not work that well with extra accessories. I'm pretty sure they will work fine with most every light except for possibly the Luxos U. Luxos B should be ok.

I've wondered if those 1.5w hubs are the ones that the Citibikes use. The Citibike lights are pretty modest. Next time I take one out I'll have to take a look.

I see...so aside from mechanical things like size and width, the differences between the two brands aren't all that huge: the voltages are still the same, the guts are different, but operate on the same principle. That would mean something like this https://www.bike2power.com/LightCharge-Chargers would actually be redundant: you'd only need one adapter to fit them both?

The difference between those is just the plug at the dynamo. For some reason they use different connectors. For the Shimano I have, you take the bare wires and push it through the top part, wrap it up, and click it onto the hub. I think the SON uses flat disconnects that you can buy at any Radio Shack or Home Depot, but are probably also supplied with the hub and pre-wired for this device. I don't know why one would be more expensive than the other.

That does seem odd I agree. I use a PedalPower+ Super-I-Cable which I use with both a Shimano and a SON dynamo. Only difference is the connection to the actual dynamo.

Andrew

B&M makes both, but they make Bottle generators. , not hub center sorts.

Schmidt makes No Taillights..


Schmidt has a 2 wire 2 spade lug connection , at the hub..

Shimano has made their own 2 bare wire plug.
it comes out in 1 piece to pull wheel.

Thanks, zacster. Do other brands of hubs follow one or the other of these connections, or are they all different in this regard?

Shutter Precision uses the same type of connector as the Shimano. Whether they are interchangeable I can't tell you.

I think some provide a frame ground to one of the connectors.

According to Peter White Cycles, both Shimano and Sanyo hubs ground to the frame via the axle.

That shouldn't affect compatibility with devices, though. You would just need to make sure you're not shorting the circuit by connecting the power wire to ground.

There must not be enough conductivity in my frame, or at least around the axle. I used my digital multi-meter and it didn't show a continuous circuit between either either side of the connector and the frame on my Shimano hub.

Shimano axles are aluminum, it isn't likely to make good contact. Are your dropouts clean metal?
according to my tests, they do interchange

Bit of trivia for you that may be of interest.
Whilst I currently use a Son28 hub to power my lights, gps and phone my first dynohub was one of the vintage Sturmey Archer GH6 models.
When I became aware of the new led headlights a couple of years ago, I ordered a Son hub and Edelux headlight.
This initially tapped me out financially for a short period of time and I couldnt afford to get my Son hub made up into a wheel.
I decided to try to see if my Sturmey GH6 would in any way wake up the Edelux headlight.
I didnt have much faith as the GH6 was reputed to be around 1.8 watts.
Well happy to report it worked fine.
So well in fact that if I hadnt already bought the Son dynamo hub, I'd likely not have bothered.
I'm glad I did, not so much because its likely the Son offers more output or perhaps less drag, but because the GH6 weighs in at around 1.1kg from memory, which is more than double the Son.
My bike was already heavy so swapping out the hub and sprung leather saddle for a Ti framed Brooks Swift meant a large weight saving.

I should probably add my bike at the time was a Moulton APB which utilises 20' wheels, meaning the hub was rotating faster than a larger diameter wheel of say 700c and thus putting out more power than the 700c or 26' would have.

A GB-based tester found his old 6V Dynohub, rated at 1.8W output, drew 1.0W unloaded and 2.6W powering a 1.5W lamp - competitive efficiency with today offerings, and too little drag in either case to be detectable by the rider. Fed into the best of today's LEDs, one can make useful light. They're still heavy, though!

Back to my original comment, the 6V Dynohubs have fewer poles than today's generator hubs and tend to flicker (26-28" wheels) with LED lights without a battery in the circuit to smooth the power. Sturmey also made 8V and 12V Dynohubs.