Thorn Cycles Forum
Technical => Lighting and Electronics => Topic started by: RonS on December 02, 2013, 11:02:01 PM
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So, I have a B&M IQ Cyo headlight and a toplight line taillight powered by a Shimano 3N72 hub dynamo. The toplight line supposedly makes it easier for motorists to judge distance. I think it would be easier still if the bike had two, separated lights, the toplight on the rack and perhaps the new Secula on the fender.
I have no idea how much current the new LED lights draw. Do the German regs require LED lights to draw 2.4 and .6 Watts like the old incandescents, or would a 3W dynamo be up to the task?
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I have a 3W hub generator, it powers two rear lamps (B&M Line Plus on the rack and Seculite on the mudguard) and one front lamp (B & M Cyo 60).
My generator is a SON Klassik, any other 3W generator ought to work as well.
With the extra rear lamp, you might need slightly more speed to get the lamps to the same level of brightness, but I haven't noticed any difference.
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I am pleased I decided to check in and use the search function :)
I am thinking of running two Busch & Muller Busch & Muller Secula Plus for Seat Post or Stay (331/2ASK) (http://www.bumm.de/produkte/dynamo-ruecklicht/secula.html) rear lights in-combination with a Busch & Muller Lumotec IQ2 Luxos U (http://aushiker.com/busch-muller-lumotec-iq2/) front light. All of which will be powered by, a SP PD-8 dynamo (http://www.sp-dynamo.com/8seriesdynamo%20hub.html) mounted in a 20" wheel.
Sounds like this might be a go. Fair call?
Regards
Andrew
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Fair call?
Hi Andrew!
While I have not used this exact combination myself, I'd say it falls firmly into the "should work" category.
Worst-case, you could sell-on one of the Seculas and substitute an LED blinky if the two didn't work, but I think you'll be fine.
Best,
Dan.
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Hi Andrew!
While I have not used this exact combination myself, I'd say it falls firmly into the "should work" category.
Worst-case, you could sell-on one of the Seculas and substitute an LED blinky if the two didn't work, but I think you'll be fine.
Best,
Dan.
Thanks Dan. I think I will give a shot. I have read but that the Secula does draw "high power" so I may loose a touch of front light I guess.
Andrew
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Just got my shipping notice from Bike24 that the Secula is en route. I should be able to report in a couple of weeks how well a Secula / Toplight Line Plus / IQ Cyo combination works. If two taillights draw too much current, there is a battery version of the Toplight Line.
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Just got my shipping notice from Bike24 that the Secula is en route. I should be able to report in a couple of weeks how well a Secula / Toplight Line Plus / IQ Cyo combination works. If two taillights draw too much current, there is a battery version of the Toplight Line.
That would be great. I don't have a rack on the bike so the likes of a couple of Secula appeals.
Andrew
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I have to IQ Cyo headligts on my bike and a flashing batterylight.
http://www.flickr.com/photos/bicycletour-dk/11407643984/in/photostream/
Best infoside
http://www.peterwhitecycles.com/wiringinstructions.asp
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Good news from your practical experience and usage, Andreas; thanks. For a long time, Thorn/SJS Cycles made a very nice mount for dual headlights that proved helpful with those mounting needs, but it appears they're down to just the single light version now: http://www.sjscycles.co.uk/thorn-alloy-dynamo-headlamp-bracket-m5-fork-crown-mounting-black-prod12373/?geoc=us
I'll miss the availability of the double headlight bracket if it is now truly gone; it was a beauty!
Best,
Dan.
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I am guessing that two tail lights in parallel would work ok. But if you find you are draining too much current from the head lamp, then try running the tail lights in series. They might be dimmer in series however so I would try parallel first.
My thoughts above are only a guess, I have run two headlights in series without a tail light. (My taillights are battery powered.)
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I am guessing that two tail lights in parallel would work ok. But if you find you are draining too much current from the head lamp, then try running the tail lights in series.
On the two bikes I have with two rear lamps powered by the hub generator they are connected in parallel.
I haven't tried series connection, but suspect that it wouldn't work well with LED lamps.
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I have two of the Secula lights on order from Bike24.net so I guess I will find out soon enough if they will work or not :)
Andrew
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On the two bikes I have with two rear lamps powered by the hub generator they are connected in parallel.
I haven't tried series connection, but suspect that it wouldn't work well with LED lamps.
LED bicycle lamps are designed to drop or to be made up in sets to drop the 6V nominal that a hub dynamo produces. This could be one lamp dropping a notional 3W, or a headlamp at 2.4W plus a tail lamp at 0.6W. In the filament and halogen days, BUMM lamps used to tell you in the specs and also in the serial number whether the headlamp was 3W or 2.4W, and all rear lamps were 0.6W. Today you may assume that a front BUMM LED lamp with an outlet for a tail lamp will drop 6V with or without the tail lamp attached. An additional lamp or set of lamps must thus be fitted in parallel. There may be exceptions (perhaps where the LEDs are supposed to do double duty as rectifier diodes, in which case they would be wired in opposed series-parallel, recommended for DIYers who know what they're doing) but I don't know of any in the sort of commercially sold lamps we would normally consider. These considerations are slightly, but only slightly, complicated by the knowledge that almost all common dynamos running without load will rise at the output to at least 7.2V and some higher, because the nominal 6V rating presupposes full load. But modern LEDs are quite strong, quite possibly today more sensitive to overheating than to moderate overvolting, so breakages are likely to be rare.
SUMMARY
The safe thing to do with LED lamps in the absence of hard information, knowledge and instruments, is to series one headlamp with one tail lamp, and to parallel the next lamp or set.
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SUMMARY
The safe thing to do with LED lamps in the absence of hard information, knowledge and instruments, is to series one headlamp with one tail lamp, and to parallel the next lamp or set.
With a headlamp designed to work with a hub generator (i.e. with a manual or automatic switch), is the tail lamp connected to the headlamp output working in series or in parallel ?
I thought the only reason not to connect the tail lamp directly to the generator (so in parallel) was to benefit from the on/off switch in the headlamp.
With bottle dynamos, I always connect the headlamp and tail lamp in parallel, three of the family bikes still have this setup.
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With a headlamp designed to work with a hub generator (i.e. with a manual or automatic switch), is the tail lamp connected to the headlamp output working in series or in parallel ?
I thought the only reason not to connect the tail lamp directly to the generator (so in parallel) was to benefit from the on/off switch in the headlamp.
With bottle dynamos, I always connect the headlamp and tail lamp in parallel, three of the family bikes still have this setup.
Well, you would mount two filament lamps, 6V each, in parallel. You would also mount in parallel two LED lamps, one 6V, one a lesser voltage but with a built-in circuit to reduce 6V form the generator to whatever voltage the LED requires.
In each case it depends on what protection circuit for the lamp is already in place.
The advantage of a series connection, if the voltages of the LEDs add up to generator voltage, is that no energy is wasted in heating dropper components. But, if there are other circuits already built into the lamps to control the voltages, then parallel connection would work best.
At bicycle voltages/current you are unlikely to do much damage if you get it wrong.
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Many headlight units have a place to plug the taillight connectors into. Check your instructions and if it includes instructions on wiring both lights, follow the instructions.
The only time you would want to run any lights in series is if they both use the same amount of current.
My two headlight setup is an example, both headlights are the same model so have exactly identical requirements. And my taillight is battery powered, so that simplifies it when only my headlights are in the circuit.
But a headlight and taillight will have different current requirements, I would not be surprised if attempting that in series damaged something.
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One important point to note wrt LED dynamo lighting:
LEDs require DC voltage, and most LED taillights lack a rectifier of their own and so depend on a circuit in the headlight to convert AC to DC for proper operation. My tests show not all (i.e. "few" or "no") LED taillights have voltage limiters, so also depend on the headlight for that.
Best,
Dan.
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LEDs require DC voltage, and most LED taillights lack a rectifier of their own and so depend on a circuit in the headlight
I suppose most B&M tail lamps must be an exception then.
I still have B&M Seculites on 2 bikes and one of the older B&M Toplights on 1 bike, connected directly to bottle dynamos in parallel with LED front lamps. I had similar systems on nearly all family bikes before I started using hub generators, initially with front halogen/rear LED before front LED lamps became available.
I never had any problems with the LED tail lamps, even if used for a few kms with a failed (halogen) front lamp (which is probably not recommended).
Going further back in time, rear lamps with filament bulbs would burn out almost immediately if the front lamp failed.
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I suppose most B&M tail lamps must be an exception then.
That could well be, Martin. I wonder if it is all of them? When I mounted a B&M Line Plus on my SON28-equipped Extrawheel trailer, I was unable to get it to work until I designed and built a voltage rectifier/limiter for it. It worked fine, then.I still have B&M Seculites on 2 bikes and one of the older B&M Toplights on 1 bike, connected directly to bottle dynamos in parallel with LED front lamps.
I don't doubt it for a moment, I just wish there was a way of determining for sure in advance of purchase. I wrote B&M and asked, and was advised to wire the taillight directly to the headlight -- only. I do know the model with the brake-light function requires different wiring from others, and some of B&M's models initially did not play well with the Luxos headlight. Perhaps they vary from model to model or perhaps they change from time to time in production?Going further back in time, rear lamps with filament bulbs would burn out almost immediately if the front lamp failed.
<nods vigorously> Boy! I'll say; mine lasted about a nanosecond after the headlights blew, back in the days when I used filament bulbs.
Best,
Dan.
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But a headlight and taillight will have different current requirements, I would not be surprised if attempting that in series damaged something.
We have run B&M Cyo and Seculite in series with no adverse effects. The lights both ran at expected outputs. Having said that it is not ideal as should one light fail the whole lot is out of action.
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I suppose most B&M tail lamps must be an exception then.
I still have B&M Seculites on 2 bikes and one of the older B&M Toplights on 1 bike, connected directly to bottle dynamos in parallel with LED front lamps.
+1
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Well, I finally got around to trying out the Secula/Toplight combo along with my Cyo headlight. I had given the light to my daughter to test as the dynamo was on her bike at the time. 21 year old ladies are not really too keen on doing experiments for dad though, so the light got "misplaced" under whatever was heaped in her dorm.
Now that the dynamo wheel and lights are now on the Raven, I can say that there is plenty of juice from the dynamo to power everything. I tried running one tail light and two and can't tell any difference in light output. The lights are wired in parallel, using the tail light output wires on the headlight.
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I can say that there is plenty of juice from the dynamo to power everything. I tried running one tail light and two and can't tell any difference in light output. The lights are wired in parallel, using the tail light output wires on the headlight.
Thanks for checking back in with the firsthand report and update, Ron; I'm sure this will prove helpful to others in the future.
Best,
Dan.
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Now that the dynamo wheel and lights are now on the Raven, I can say that there is plenty of juice from the dynamo to power everything. I tried running one tail light and two and can't tell any difference in light output. The lights are wired in parallel, using the tail light output wires on the headlight.
Thanks for the update. I am still to get mine setup. Small problem my wheel building skills has delayed things somewhat :)
Andrew
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Now that the dynamo wheel and lights are now on the Raven, I can say that there is plenty of juice from the dynamo to power everything. I tried running one tail light and two and can't tell any difference in light output. The lights are wired in parallel, using the tail light output wires on the headlight.
Thanks for that, Ron.
It sounds like you have two taillights in parallel, the pair in series to the headlamp. Your remark about "plenty of juice" raises the further question:
How much current would a SON actually produce if loaded up with enough devices (lamps, GPS being recharged, etc) to keep the voltage down to 6V at the first LED.
And another question:
Presuming rectification but no regulator circuit in the lamp (neither of which we know for a fact), if the load was enough to bring the voltage down to 5V, would the LEDs still work, and how effectively?
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Peter White has shed a bit more light (sorry!) on the matter of multiple dyno-powered LED *head*lights here: http://www.peterwhitecycles.com/wiringinstructions.asp
CYO, Edelux and Supernova E3/E3Pro headlights can all be "doubled up", You can use two CYOs, two Edelux or two Supernova E3. But don't mix and match between brands. That hasn't been tested.
Best,
Dan. (...who bemoans the apparent discontinuation of the dual-light version of Thorn's alloy mounting bracket, now available only as a "single": http://www.sjscycles.co.uk/thorn-alloy-dynamo-headlamp-bracket-m5-fork-crown-mounting-black-prod12373/?geoc=us )
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I usually make my own light brackets anyway. A bit of strap Aluminum, a drill, some drill bits and an M5 or M6 tap is all it takes. Sometimes I get fancy and spray on some matt black primer when done.
I sometimes run a single Lumotec oval, sometimes a double setup. In both cases I am using home made brackets.
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Presuming rectification but no regulator circuit in the lamp (neither of which we know for a fact), if the load was enough to bring the voltage down to 5V, would the LEDs still work, and how effectively?
While I was tidying up the wiring today I did a low tech test. Poke the probe wires from my multimeter into the back of the connectors for the wires going to the tail lamps and give the wheel a spin. I got just over 6V AC, so, in the Cyo at least, there is no rectification in the output to the tail lamp. I didn't spin the wheel fast enough to to see how many volts I could get. I'll have to get some alligator clips for that test. All in the name of science.
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While I was tidying up the wiring today I did a low tech test. Poke the probe wires from my multimeter into the back of the connectors for the wires going to the tail lamps and give the wheel a spin. I got just over 6V AC, so, in the Cyo at least, there is no rectification in the output to the tail lamp. I didn't spin the wheel fast enough to to see how many volts I could get. I'll have to get some alligator clips for that test. All in the name of science.
It proves, though, that your two rear lamps are not overloading the hub dynamo, even at modest speed.
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One important point to note wrt LED dynamo lighting:
LEDs require DC voltage, and most LED taillights lack a rectifier of their own and so depend on a circuit in the headlight to convert AC to DC for proper operation. My tests show not all (i.e. "few" or "no") LED taillights have voltage limiters, so also depend on the headlight for that.
Best,
Dan.
Nicelite bulbs can run anywhere between 1.5 volts to 9volts and always be the same brightness. Fitting batteries the other day the light takes 4 but light will work on 2. So appeared to be normal brightness at 1.2 volts