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  1. #1
    Member roguehippie's Avatar
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    Dynamo Hub/light setup vs. Traditional

    Hi All,

    Well, the Kona commuter is rockin' hard now, and I've gotten into that rut where I constantly want the next cool thing. So . . .

    Since lighting is an honest-to-god issue for me (I ride 10 of my 15 miles in unlit conditions and it's dark out there in "god's country"), I've been considering a new light.

    I can:

    A) Spend $85.00 and get a nice 10W halogen setup with rechargeable battery
    B) Spend $50.00 and get a high-powered emitter from NiteHawk but I know nothing about them. (Anyone? Anyone?)
    C) get a dynamo wheel (Shimano hub type) and light set-up for roughly $200 and feel all cool about generating my own power, not having to use batteries, etc.

    Does anyone have experience with dynamo hubs and their impacts on your ride? Do the 3, 6W halogen lights that work with them produce a lot of light, or are they simply like CatEye lights without the need for batteries?

    I've got a 5 LED blinker on my handlebar which is great for making me seen, but I'm more or less "using the force" on the dark sections of my ride to and from work.

    Any input would be appreciated!

  2. #2
    Senior Member randya's Avatar
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    What exactly does 'traditional' mean? For bikes, I suppose that would be a carbide lamp...

    http://wasg.iinet.net.au/clamps.html
    http://www.websolutionswa.com/lamps/miller.html

  3. #3
    Senior Member randya's Avatar
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    Quote Originally Posted by roguehippie
    get a dynamo wheel (Shimano hub type) and light set-up for roughly $200 and feel all cool about generating my own power, not having to use batteries, etc.

    Does anyone have experience with dynamo hubs and their impacts on your ride? Do the 3, 6W halogen lights that work with them produce a lot of light, or are they simply like CatEye lights without the need for batteries?
    IMO, this is the way to go. Brightness shouldn't be an issue; the beam pattern of the lamp you choose is probably the most important consideration. Old Union lamps, B&M lamps and some other brands produce a good focused beam.

    Best US source I've found on the web is Peter White Cycles: http://www.peterwhitecycles.com/lightingsystems.htm

    Search these forums and you will find several older threads addressing the questions you are asking.

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    Quote Originally Posted by roguehippie
    Hi All,

    Does anyone have experience with dynamo hubs and their impacts on your ride? Do the 3, 6W halogen lights that work with them produce a lot of light, or are they simply like CatEye lights without the need for batteries?
    !
    I'm very happy with mine. It is definitely a "see" light, rather than just a "be seen" like the CatEye. A lot clearly depends upon the light that you run. My Lumotec gives a bright, very well-focused beam. It works very well on the routes I ride.

    Personally, I would not consider any other lighting solution -- too much hassle. I just want to jump on the bike and go. Your priorities may be different.

    Paul

  5. #5
    Retrogrouch in Training bostontrevor's Avatar
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    I once went on a night ride with a guy with a carbide lamp. It was pretty awesome. I still don't know if it was legal, but way cool. I'm not entirely sure what it was burning but dude had some sort of fuel cell in the back of the bike with a rubber hose up to the lamp itself.

  6. #6
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    The hub dynamo is great. No doubts about the battery charge. It's there ready to roll at any time. I love my SON.

    As to the lights, the optical design of the lens and reflector are what work, not the power of the globe. I ride lots at night on randonnees with people who have spent small fortunes on battery lights. They still don't measure up to the Lumotech Ovalplus, and now the B&M E6.

    For urban riding, go with the Ovalplus with the LED that remains lit from energy stored in a capacitor for around 5 minutes. Helps you get seen at junctions when the main globe goes out on stopping.

    For best use of light output, the E6 reigns supreme, but is not available (I don't think) with the LED.

    I have one Ovalplus as a primary light and an E6 as a secondary for my randonnee bike which serves more often that not as a commuter.

    The commuter I plan on building will have a the latest Shimano hub dynamo with a single Ovalplus.

  7. #7
    Senior Member rainedon's Avatar
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    Quote Originally Posted by Rowan
    The hub dynamo is great. No doubts about the battery charge. It's there ready to roll at any time. I love my SON.

    As to the lights, the optical design of the lens and reflector are what work, not the power of the globe. I ride lots at night on randonnees with people who have spent small fortunes on battery lights. They still don't measure up to the Lumotech Ovalplus, and now the B&M E6.

    For urban riding, go with the Ovalplus with the LED that remains lit from energy stored in a capacitor for around 5 minutes. Helps you get seen at junctions when the main globe goes out on stopping.

    For best use of light output, the E6 reigns supreme, but is not available (I don't think) with the LED.

    I have one Ovalplus as a primary light and an E6 as a secondary for my randonnee bike which serves more often that not as a commuter.

    The commuter I plan on building will have a the latest Shimano hub dynamo with a single Ovalplus.
    I have been pondering this question for a long time and hopefully one of you guys can set me straight. I have a 1 mile descent in my morning commute where I typically reach speeds of 25+mph. 9 months of the year I'm riding before sunrise and this road is pitch black and I'm in Oregon, so the roads are often wet. I am using a Light and Motion Solo 13 watt halogen lamp. I am satisfied with this light and its illumination at these speeds in these conditions. When this light/battery fail, I am really interested in replacing it with a generator setup. Will a generator hub with one of the available lamps (most seem to be 3 watt) give comperable light and intensity and make me equally as satisfied as my Light and Motion? Does a 3 watt bulb on a generator system somehow give off as much light as a 13 watt bulb on my NiMH system?

    Thanks
    nate

  8. #8
    Mad bike riding scientist cyccommute's Avatar
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    Quote Originally Posted by bostontrevor
    I once went on a night ride with a guy with a carbide lamp. It was pretty awesome. I still don't know if it was legal, but way cool. I'm not entirely sure what it was burning but dude had some sort of fuel cell in the back of the bike with a rubber hose up to the lamp itself.
    Perfectly legal and still obtainable. Some cavers still use them as a primary light. I have a Justrite lamp, and 2 carbide bicycle lamps (nonfunctional). I also use Bangsite in a carbide cannon.

    Calcium carbide is a "salt" of acetylene. Add water, the water pulls off the calcium ions and makes calcium hydroxide and acetylene. The acetylene is directed to a jet that is ignited and, viola, light! The more water dripped on the carbide the more acetylene is produced and the lamp gets brighter.

    Stuart Black
    "It's all chemistry."

  9. #9
    Senior Member randya's Avatar
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    Quote Originally Posted by Rowan
    ...power of the globe...
    It sounds so awesome!!! In the US it would be a bulb - you guys down under sure have a funny way of saying things...

    The B&M Oval and Oval plus both throw a good focused beam. I still like the optics of the old W. German Union lamps better, though.

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    Quote Originally Posted by rainedon
    Will a generator hub with one of the available lamps (most seem to be 3 watt) give comperable light and intensity and make me equally as satisfied as my Light and Motion? Does a 3 watt bulb on a generator system somehow give off as much light as a 13 watt bulb on my NiMH system?
    No, and no.

    Nifty reflectors and precise aiming are great, but at the end of the day you're talking about a 3 watt headlight. There's just only so much light you're going to get from that thing. In no way will it be the equal of your 13W lamp.

    The biggest drawback to the generators, in my view, is that the lamps are so dim compared to battery lights near their cost.

    A second drawback is that they rob you of a significant amount of power, ~7W for the best hub generators. The drain is smooth, so you don't notice it directly as increased rolling resistance, but if you do the calculations you see that this power drain robs an ordinary rider of ~1/5 - 1/2 mph speed on flat ground. One scenario would be a minute loss per hour, at ~20 mph. Another scenario would be a loss of nearly two minutes per hour at ~17 mph. For that amount of speed *gain*, some people pay several hundred dollars for aero wheels, to give some perspective on the power cost of the generator.

    Another way to put it is that a rider can carry a *lot* of weight in batteries, several pounds worth, and still use less power to to go a given speed than with the hub generator. 7W of power will buy you over five pounds of batteries on a slight uphill slope, never mind on level ground-- that's *way* more than enough batteries to run a light through the night. And that battery light could be *much* brighter than a generator-powered lamp.

    Still, generators bring great convenience compared to batteries, that is true. Some of the better systems have auto switches. They'll come on whenever it's dark. They're very cool.

    But as far as performance in illumination and rider speed, they're far behind battery lights.

  11. #11
    Senior Member randya's Avatar
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    You can argue wattage all you want, but dynamo systems with halogen lamps are plenty bright for both being seen and illuminating the road. I could show you a 15 watt tube audio amplifier that would knock the socks off a solid state unit ostensibly rated at 10 times the wattage.

    Drag is noticeable with some dynamos but not that significant unless perhaps you are racing; it's less with a hub system than a sidewall tire drive (although there are several low drag sidewall dynamos on the market now, including the B&M S6 and the Swiss-made Lightspin).

    Dynamo fact and fiction: http://www.myra-simon.com/bike/dynamos.html
    Comparison of dynamo performance: http://www.myra-simon.com/bike/dynotest.html
    Schmidt hub review: http://www.myra-simon.com/bike/schmidt.html

  12. #12
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    Quote Originally Posted by Merriwether
    No, and no.

    Nifty reflectors and precise aiming are great, but at the end of the day you're talking about a 3 watt headlight. There's just only so much light you're going to get from that thing. In no way will it be the equal of your 13W lamp.

    The biggest drawback to the generators, in my view, is that the lamps are so dim compared to battery lights near their cost.

    A second drawback is that they rob you of a significant amount of power, ~7W for the best hub generators. The drain is smooth, so you don't notice it directly as increased rolling resistance, but if you do the calculations you see that this power drain robs an ordinary rider of ~1/5 - 1/2 mph speed on flat ground. One scenario would be a minute loss per hour, at ~20 mph. Another scenario would be a loss of nearly two minutes per hour at ~17 mph. For that amount of speed *gain*, some people pay several hundred dollars for aero wheels, to give some perspective on the power cost of the generator.

    Another way to put it is that a rider can carry a *lot* of weight in batteries, several pounds worth, and still use less power to to go a given speed than with the hub generator. 7W of power will buy you over five pounds of batteries on a slight uphill slope, never mind on level ground-- that's *way* more than enough batteries to run a light through the night. And that battery light could be *much* brighter than a generator-powered lamp.

    Still, generators bring great convenience compared to batteries, that is true. Some of the better systems have auto switches. They'll come on whenever it's dark. They're very cool.

    But as far as performance in illumination and rider speed, they're far behind battery lights.
    You simply don't seem to know what you are talking about.

  13. #13
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    Quote Originally Posted by Rowan
    You simply don't seem to know what you are talking about.
    Well, if it seems that way to you it's because you don't understand the facts about generator lighting. And there isn't much point in your arguing about it. Do the calculations yourself. Start at analyticcycling.com. Or don't. I don't care. Either way, the facts are what they are.

  14. #14
    Retrogrouch in Training bostontrevor's Avatar
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    Quote Originally Posted by cyccommute
    Calcium carbide is a "salt" of acetylene. Add water, the water pulls off the calcium ions and makes calcium hydroxide and acetylene. The acetylene is directed to a jet that is ignited and, viola, light! The more water dripped on the carbide the more acetylene is produced and the lamp gets brighter.
    Right, which is why I wonder if it was legal. Carbide lamps are self-contained. This had some sort of fuel cell with a rubber hose running from the cell in the back to the lamp in the front. I suspect that there was no carbide involved but straight up bottled acetylene. The fire marshal might have something to say about that.

  15. #15
    Dominatrikes sbhikes's Avatar
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    I wish I had a dynamo light instead of the Nightrider light I paid $120 for. Maintaining the battery is just too complicated.

    If the battery just needs to be "topped off" (how do you know??) you charge for 4 hours. That means I'd have to charge it as soon as I get home and stay up until at least 10pm (I go to bed early) so I can be sure to unplug it in time. Don't forget!

    If the battery is exhausted (which you aren't supposed to do), charge it for 9 hours. The only way I can do that without setting an alarm clock for the middle of the night is to charge it at work. That I don't mind, but what if the battery isn't exhausted yet, but there's not enough power to get home? There's nothing to indicate this.

    Dynamo sounds perfect. No babysitting batteries.
    ~Diane
    Recumbents: Lightning Thunderbolt, '06 Catrike Pocket. Upright: Trek Mountain Bike.
    8.5 mile commute. I like bike lanes.

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    Quote Originally Posted by randya
    You can argue wattage all you want, but dynamo systems with halogen lamps are plenty bright for both being seen and illuminating the road. I could show you a 15 watt tube audio amplifier that would knock the socks off a solid state unit ostensibly rated at 10 times the wattage.
    What "plenty" is for you I suppose you're best fit to say. As far as comparisons to other lights are concerned, the good headlamps for generator lights are about as bright as brighter caving headlamps. So, to my mind, they're very good be-seen lights, and mediocre seeing lights.

    I say "mediocre", and not "bad", or "unuseable", just to be clear. I've got a halogen caving headlamp that's about as bright as an acquaintance's generator-driven halogen headlamp (she's got a Schmidt hub generator), and that headlamp is a serviceable backup. It's not great. I certainly can't see the road-- I mean really *see* it, as opposed to inferring and guessing about a lot of what's there-- making 20+ mph descents. But it's not bad, either. I can see *some* of the road, and well enough to travel comfortably at less than 15mph.

    By comparison, the rechargeable battery halogen light systems are certainly brighter than generator powered lights. There's no question, for example, that a 13w halogen Light and Motion system is much brighter than the lamps powered by generator hubs. This is just a matter of easily observable fact; it's not a matter for debate. The poster I was responding to was asking precisely about this comparison, and it's not just fair but accurate to say that he will be losing a lot of light moving to a 3w halogen headlamp from what he's got now.

    The primary advantage of a generator hub is its continuous provision of power, whenever light is needed. This is greatly convenient-- no worries lighting. It's also safer than running a risk of your batteries going dead, though that worry can be partly alleviated, of course, through proper battery maintenance and carrying a backup (each of which adds to the inconvenience of battery lighting, though). The cost of this convenience is greatly reduced light compared to comparably priced battery powered systems, and, as I said above, a larger speed cost than some people imagine to the rider, too.

    But a generator might well recommend itself to someone. I don't say otherwise. I don't see why we shouldn't be clear about the drawbacks as well as the advantages, though.

  17. #17
    Senior Member ollo_ollo's Avatar
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    I have multiple bikes & several lighting systems: rechargable battery powered 10watt & 15watt halogen bar lights, a 3watt LumoTec Oval+ light driven by a Sturmey Archer Dyno Hub, a 3watt halogen light driven by a Soubitez bottom bracket generator and a 3watt halogen light driven by a Union sidewall generator. The 10 & 15 watt systems provide much more & brighter light with better visibility than the 3 watt systems, especially above 20 mph but as others have said, battery charging is a nuisance. But the 3watt systems are definitely an improvement over a 5 led blinker & give acceptable light on a dark road if I respect a 15 to 18mph limit. Higher speeds are risky without more light or bright streetlights. I took a fall this Winter when my 15watt light went out unexpectedly on a dark country road. I was fiddling with the cable trying to get it working again & veered off the pavement edge, then fell. In my experience, combining a hub generator light with a battery powered halogen light is the best solution. My favorite combination is the 10watt battery system for long run times along with one of the generator systems to give a wide & focused lit area plus some redundancy if one system fails. Also the LumoTec & some generator systems have overvoltage protection to protect the bulb on high speed descents. Don
    visit my homebuilding blog: www.monoplanar.blogspot.com

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    Senior Member ollo_ollo's Avatar
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    Forgot to mention the home made light system I built around a 55watt 12volt halogen auto backup light ($4.95 with bulb) and 2 yellow xenon strobe lights; The "total Geekiness" thread has all kinds of great "self help" solutions to the light problem if you are so inclined.
    visit my homebuilding blog: www.monoplanar.blogspot.com

  19. #19
    Mad bike riding scientist cyccommute's Avatar
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    Quote Originally Posted by bostontrevor
    Right, which is why I wonder if it was legal. Carbide lamps are self-contained. This had some sort of fuel cell with a rubber hose running from the cell in the back to the lamp in the front. I suspect that there was no carbide involved but straight up bottled acetylene. The fire marshal might have something to say about that.
    Oops. I was being a little dense

    Knock the valve off of a tank of acetylene and you could have a rocket power bike! At least for a little while. It'd be kinda Slim Pickinish!

    Stuart Black

  20. #20
    Senior Member rainedon's Avatar
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    Quote Originally Posted by sbhikes
    I wish I had a dynamo light instead of the Nightrider light I paid $120 for. Maintaining the battery is just too complicated.

    If the battery just needs to be "topped off" (how do you know??) you charge for 4 hours. That means I'd have to charge it as soon as I get home and stay up until at least 10pm (I go to bed early) so I can be sure to unplug it in time. Don't forget!

    If the battery is exhausted (which you aren't supposed to do), charge it for 9 hours. The only way I can do that without setting an alarm clock for the middle of the night is to charge it at work. That I don't mind, but what if the battery isn't exhausted yet, but there's not enough power to get home? There's nothing to indicate this.

    Dynamo sounds perfect. No babysitting batteries.

    I have a simple $5 timer from Home Depot that my charger plugs into. You know, the kind that you plug your house lights into when you go away on vacation to trick would be burglars into thinking you are home. Simply plug your charger into the battery and set the little peg in the timer to turn off whenever you want it to.

  21. #21
    Si Senior dbg's Avatar
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    I have been pleasantly surprised how bright is the lumotec (170) combined with the shimano dynamo hub. I'm sure there are battery systems that can be much brighter, however. Being somewhat of a procrastinator, I just didn't want to deal with high prices for 4 hour systems. My light is always there and my commuter bike gets no maintenance attention at all. It has to be ready at all times (trusty steed).

    BUT, remember you have to account for stopping (at intersections) and losing your headlight illumination. Also, I added a switch because I felt the rolling resistance was noticeable and I wanted to be able to shut it off when not needed.

  22. #22
    Senior Member royalflash's Avatar
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    My vote goes for the SON hub dynamo with a Lumotech Sensor Oval Plus. I cant detect any extra rolling resistance- it switches on automatically when it gets dark and does not go off when the bike is stationary. It is reasonably bright and there are no running costs.

    I combine this with a very bright helmet mounted flashing LED light.
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    This looks like the place to ask this question.
    Does anybody know how to combine the two. Batteries and a hub or tire rubber generator?
    It would be really slick to be able to charge a high powered battery while riding on say a 3 day weekend tour. Or a gps, cellphone, get the idea.
    B&M makes a 12 volt gen (tire rubber type) 6 watt output.
    By the way I love my SON too.
    I agree those 10+ watt light systems do put out more light, but how I usally ride the gens output is sufficient.

    Serious about the question and electrical engineers out there?

  24. #24
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    My commuter has a Nexus NX-30 (i.e. the cheap one on Peter White's pages) with a single round Lumotec; my tourer and tandem both have a SON with a Lumotec Oval Plus and a secondary Lumotec. Resistance is minimal, although the Nexus is noticeable when rolling at high speed with the light on, which is not a problem for commutes in stop and go traffic, but could be an "incomfort" if I rode all night on rural roads.

    As for lighting, I would compare the single Lumotec with a 8 to 10 W MR-11 light (i.e. a 10 W bulb on a brand new freshly charged battery is brighter, but after 15 minutes, the 3 W Lumotec is brighter. How come? Simply because the Lumotec and Bisi headlights focusses the light where you need it for highway riding, not in the sky. Whereas that "stray light" is useful for singletrack, it's not that useful on highways.

    For your high speed descents, the single Lumotec won't allow you to ride at full speed unless the road is already lit. With dual Lumotecs or, better, with a Lumotec and a Schmidt E-6, you will be able to go faster, but you might not go at full speed.
    Depending on your night vision, rain, snow, stray lights, etc., I would suggest a maximum riding speed of 30 km/h with a single headlight or 40-45 km/h with dual headlights, maybe 5 km less if it rains. In other words, I don't think the headlight would be a significant limitation on your ride.

    On the plus side, the generator-based headlight doesn'T limit you in how long you ride, you never need to plan your charges, and the battery doesn'T die when it's -20 C. And if you really like high speed descents, you could supplement it with a 20 W single battery headlight with an autonomy of 30-40 minutes, which won't cost you an arm and a leg because it doesn't last that long.

    One other factor that differenciates the Lumotec (or Schmidt) headlights vs cheaper ones is the current-limiting diode, which allows you to ride as fast as you want without killing your lightbulb.

    P.S. I can't assess Peter White's taillights because I use Vistalite SuperNebula taillights. That way, I didn't have wires going all the way to the back of the bike, and my lighting system works whether I ride by myself, with a trailercycle, with a child trailer... or with both.
    Michel Gagnon
    Montréal (Québec, Canada)

  25. #25
    Senior Member randya's Avatar
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    Quote Originally Posted by oknups
    This looks like the place to ask this question.
    Does anybody know how to combine the two. Batteries and a hub or tire rubber generator?
    It would be really slick to be able to charge a high powered battery while riding on say a 3 day weekend tour. Or a gps, cellphone, get the idea.
    B&M makes a 12 volt gen (tire rubber type) 6 watt output.
    By the way I love my SON too.
    I agree those 10+ watt light systems do put out more light, but how I usally ride the gens output is sufficient.

    Serious about the question and electrical engineers out there?
    Dynamo regulator:

    http://www.nscl.msu.edu/~daniel/sreg.htm

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