Michel Gagnon

Look at https://www.peterwhitecycles.com for serious dynamo stuff.

The Shimano Nexus dynohub is a very good generator -- the page at Myra-Simon assesses the performance of the older NX-10; the current NX-30 is much better --, and the Schmidt is outstanding. If you want something cheap and don't want to build a wheel, get one of the Dynotec generators with a Lumotec headlight. All the above generators will offer years and years of reliable performance.

There are a few flaws with the generic $10 generator shown at the top of the page:

- much more resistance than needed, because of poor bearings, etc.;
- no built-in voltage limiter; you will have to pedal under 10-15 km/h otherwise you will have more than 6-7 V and you will fry lamps.;
- poor mechanical parts mean you will fry the generator soon.

Regards,

MisterJ

I used one 20 years ago during my nightime work commute. It seemed to slow me down a little, but that may have been more psychological than real. It may have been just a vision thing, too. I would still have a blinkie or two for when you stop at crossings and lights.

RainmanP

OK, based on your stated use and brightness needs this discussion becomes irrelevant until you make some decisions. Here is why.

1. You will be riding in the wilderness so there will be no electricity to recharge batteries, BUT you need bright light for the type of riding you will be doing.

2. Only a high quality rechargable battery light system will provide adequate light for off road riding in the dark. We are talking at least $100.

3. The most powerful quality dynamo I know of, the Dymotec at 12V (most are 6V) will only power a 5W light and costs about $150-170. Some 6V units will power up to 4W. Mike from the Snowy Midwest knows of some 12V Chinese dynamos that are less, but I don't know anything about quality or reliability, and I don't know where you can get them.

4. Don't even think about trying the $10-20 unit from Target. You will have to strike a match to see if the bulb is lighting up.

What exactly are you planning to do? Maybe we could give you advice. Are you planning to do a tour riding off road all night without seeing civilization for weeks?

Your best compromise might be the Cateye 5-LED headlight that uses 4 AA batteries. Battery life is supposed to be very good. I have one, but I am using NiMH rechargables that I keep topped so I can't talk about specific hours of use. I believe they claim 30 hours. In your case you could just carry one or two extra sets of batteries that wouldn't weigh that much. I would suggest using only Duracell Ultras.

BTW, I have experience with most types of lights, including
Vistalite rechargable system with 5W, 10W, and 15W light heads - bright with 10W or higher, but only 1.5-2 hours per charge.

Small Cateye (HL1500?) micro halogen bulb using 4AA - 1.2W light, dim, minimally inadequate for real lighting but provides some visibility.

Dynosys LightSPIN dynamo with Hella FF lamp 4W bulb - very nice light system for commuting.

Cateye 5-LED light - seems as bright as the 4W dynamo light, adequate illumination, good battery life.

Just some things to consider. In your case, unless you are planning to do off road riding at night at speed I would go with the Cateye 5 LED light. Costs about $35, but you might find it for less.
Regards,
Raymond

FOG

I still have my old one, from 1978, and the problem was it did not light up the road enough, although it was ok where there were any street lights. I think the lights themselves are a lot better today though, so it might work.

shaharidan

https://www.bikeforums.net/showthread...ghlight=Dynamo

dont know if you saw this thread, but i thought it was a fairly informitive discussion on lights.

fubar5

What would be cool is a generator that recharges batteries..That way you could ride with a battery powered setup and get all the light you need, plus charge batteries at the same time.

isemonge

I bought one for night riding and had a huge problem with installing it (the mount resulted in a bad connection and the front headlight circuit was not earthing properly, so all the power went into the rear light and blew it), but have now bought another out of sheer determination to see if they work. Once I fixed the circuit problem and restored the integrity of the circuit it seemed super bright. I will post again next week with a more detailed analysis. I cycle on the bike path here in Sacramento and there are no lights or anything, so one really needs a bit of power...and this could be an inexpensive solution (although in terms of time it is already about the most expensive light I have ever bought :-)

randya

I only use dynamos on all of my bikes. I agree with Joe, Peter White Cycles on the web is the best source for dynamos; but you can get a B&M sidewall dynamo from Peter for a lot cheaper than the Schmidt hub. Figure on about $50 to $75 for a complete set (dynamo, headlight and taillight w/ standlight). The unit you pictured looks like a copy of the old standard Union generator. They work OK as long as your wheel is true and you don't do a lot of riding in the rain. In either case, they have a tendency to slip and may damage your tire (wheel out of true), or fail to work at a critical time (slippage in the rain). The grounding problem is easily solved by using a two wire configuration, rather than using the single wire configuration and trying to use the bike frame for the ground (earth). Two wire 18-20 guage jacketed audio speaker wire works fine. Halogen headlamp bulbs are much brighter than the standard bulbs; if the headlamp does't come with a halogen bulb, they're only about $3 each, and are interchangable w/ standard bulbs. There is some drag, but it's really not that significant.

Batteries are the US standard, but there's no real reason for that -- I say go with the dynamo! No recharging, no toxics, and it's always mounted on your bike, ready to use.

bentbaggerlen

A tire driven dynamo will wear a stip on the sidewall of the tire over time. I used to use one on one of my first touring bikes. I also hated the tire driven dynamo because it would whine when it was in use.
Go to Peter White's web space and take a look at the Schmidt Dynamo hub, I have been useing mine now for three years. It is not a cheap hub, it will last you for many years.

Dave Stohler

It's actually fairly easy to make. All you'll need is a switch and a diode (to prevent back-charging). If you are using an AC dynamo, you'll need a bridge rectifier too, in order to convert the output into DC.

isemonge

Well I commuted back and forth the other day. On the way home I used my dynamo and it seemed to work quite well, but I think that a change to a two wire configuration would put my mind at rest about grounding problems. The big thing though was the whine, it whined constantly, and although the drag was inconsequential it seemed a lot more just because of the noise, a constant reminder that you were not going as fast as you thought you were. I am going to try it a few more times, but in the long term I am not hopeful I will use it forever. One question though; if you substitute a halogen for whatever I have in there at the moment, then I presume that the drag will not increase. i.e. is a halogen extra light for no extra drag? Alan

mike

Sure, man, I have used dynamos for lighting my commute for many years. I used all kinds EXCEPT for the internal hub dynamo. It just seemed like too much work to re-lace a wheel to put the dynamo hub, but if I was really serious about bike generated lighting, I would consider it.

The cheap Target $10.00 units are "OK". The plastic cover that goes over the generator drive wheel slips on the tire, so you either have to remove or modify it. The bare metal wheel will tear up a road tire or a gumwall. They are "OK" on thick, tuff mtn bike tires.

The best frame mounted generator I ever had was a newer Japanese unit that mounted onto the front fork. The light was mounted directly with the generator, so you don't have the long wiring from the generator to the light like you do on most of the dime-store units sold in the USA. Somewhere on these forums, I discussed this Japanese generator and included a pic. That was more than a year ago, however and was probably lost to some of the server problems we have had. The only problem with this lighting system is that it mounted to the front fork. I was always concerned that it might come loose and fly into the front wheel spokes. We all know what happens next. I ended up giving the Japanese model to a friend of mine who begged for it. He loved it and I haven't heard otherwise from him since then.

The two biggest problem with the dime store generators are:

1) Wiring. This is the biggest problem. The wires work loose or wear through. I suggest that you carry a small flashlight with some electrical tape wrapped around the handle so you can do emergency repair work when needed. In fact, the wire provided with the dime store generator units is too thin/poor. USe better wiring from the start.

2) Generator/tire friction drive: The generators can get gunked up with snow in winter. Also, it takes a while to get it adjusted correctly.

In general, I like generator lighting. You always have a light and never have to worry about the battery going dead in the middle of the ride (and not have spare batteries). Generator lights seem to produce more light than most handle-bar mounted battery units that take hardware store batteries (AA, C, D, etc).

I can say this, after years of using generator lights, today I use battery powered lights - and I ride to work and home every day in the dark.

I can't say when or why I made the switch, but through it all, I gradually switched over to battery powered lights. I guess it is because the generators worked great when they worked and they were pretty reliable BUT... when they didn't work and it was something more than just wiring, they were a big head-ache; more of a head-ache than just switching batteries.

Maybe if I had a reliable hub mounted dyno, I would still be using it today.

mike

Good question. You can find out for under a buck - try it and see. Let us know how it works.

Like you said, the drag is not so great as to cause concern. When I was a kid and weighed about 90 lbs, I thought grandma's bike had a lot of drag with the generator light on. As a thick legged adult, it does make some difference, but the trade-off for having light is worth it. Of course, I don't spend a lot of time going up-hill either.

rjtokyo

They're used en masse here in Tokyo and seem to be very durable. Here are a couple of drawbacks to keep in mind though:
1) The drag on your tire is very noticable; it feels like you're towing another bike behind you. Doesn't seem like it puts much wear on the tire itself though.
2) If you slow down, the light of course dims noticably, or even disappears.
3) They make a pretty loud whining noise.
If none of these bothers you, give it a try. Just don't get the kind that place the rubber roller on your rim. In wet conditions the rollers don't move and you get no light.

rjtokyo

Have you considered a dual lighting setup? That's what my wife's got on hers. Primary lighting coming from an internal front hub generator. Every so often though, from hitting potholes, bumps, or whatever, some connection gets loose and she loses her light. If that happens, she's got a secondary, handlebar mounted 2-C cell halogen. If your battery light is only secondary, you shouldn't have to replace batteries very often, but if your generator light happens to whack out, you're not stuck in the dark???

randya

I've got a rarely used backup battery light too, but mostly I rely on the dynamo. I generally only need the backup light on very wet rides if the dynamo begins to slip on my wheel. BTW-I'd trouble shoot the connections at the lamp and bulb if you've got a problem with losing light when hitting bumps, etc. Among problems I've like this are poor or loose ground connection at the lamp housing, and insufficient tension on the spring contacting the back of the bulb.

I'm also interested in continuing the previous discussion regarding charging batteries with a dynamo while riding. First of all, many better dynamo lamps and taillights now have a 'standlight' circuit that stores enough charge in a capacitor to keep the lamp on for 5 minutes +/- after stopping, so you still have lights while you're waiting at an intersection, for example.

There was also a previous post with some comments on charging conventional rechargeable batteries with a dynamo, that discussed use of rectifiers to rectify AC output and diodes to prevent backcharging.

My comments on this are that rectification should seldom if ever be necessary with a bicycle dynamo, as I believe almost all bicycle dynamos put out DC and not AC current. If they put out alternating current, they would probably be called 'alternators', and not generators. The output rating and type of current should be indicated on the dynamo shell.

Since diodes only allow for one way current flow, it makes sense to me that the use of a diode in the charging circuit would prevent backcharging or draining of the batteries while you are charging them.

IMO, that still leaves two unresolved issues:

1. How do you control the rate of charging, and is this necessary or not?

2. How do you control overcharging (shutting off the charging system) when the batteries are fully charged, and is this necessary or not?

It seems like once all these questions are answered, a pretty simple schematic could be drawn up, and such a charging device could be built inexpensively with readily available electronic components.

Also, there are some very low drag bottle dynamos on the market today. They cost a little more, but if efficiency and drag are significant concerns for you, you might try one of these low drag models. You will pay more for one of these units (figure $100.00 +/- for the dynamo alone, excluding lamps), but it may be worth it to you.

B&M Dymotec S6, available from Peter White Cycles:
https://www.peterwhitecycles.com/dymotec.asp

Dynosys Lightspin, not sure about US distributor:
https://www.dynosys-ag.ch/indexe.html

bentbaggerlen

Take a look at
https://www.nscl.msu.edu/~daniel/regulator.html
https://www.nscl.msu.edu/~daniel/sreg.htm

I use my Son Hub to recharge ni-cads when on tour.

randya

Thanks! I haven't studied them in detail yet, but these look like totally excellent links for simple electronic regulators and battery chargers for bicycle dynamos. From the schematics, these look like reasonably easy projects to build, for anyone with a little experience w/ electronics, either as a hobbyist or as a commercial assembler, that knows how to read electronics schematics and operate a soldering iron. Cool!!!