Rear dynamo lights

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Bmblbzzz
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Re: Rear dynamo lights

Post by Bmblbzzz »

wirral_cyclist wrote: 27 Sep 2022, 3:42pm
axel_knutt wrote: 27 Sep 2022, 3:27pm
simonineaston wrote: 27 Sep 2022, 7:56amit's less easy to judge the distance to a flashing light.
It's less easy to judge the distance to a light that hasn't been noticed, too.
And a 50% flashing light is only on half the time, so much more easily missed.
Theoretically. In practice that would be true if the off time was greater than the likely gaze time in any one direction, which is not the case. Flashing bike lights tend to flash from twice to several times per second, so the off time is mere fractions of a second. Think of flashing lights on emergency vehicles, their off period doesn't make them easier to miss. Even the long off period of a lighthouse doesn't, because it matches the gaze time and visibility of a person keeping watch at sea.
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mjr
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Re: Rear dynamo lights

Post by mjr »

A big steady light is plenty noticeable. Drivers rarely hit cyclists because they haven't seen them. (Smidsy is a lie!) It's more often because they don't care enough to steer clear and sometimes that they've misjudged a distance.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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zenitb
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Re: Rear dynamo lights

Post by zenitb »

Like others on here I combine the B+M rear dynamo constant light, with some "add on" AAA driven battery flashers. These last ages and I have two of them the setup is "fault tolerant" of battery failure. I feel the flashers give a bit more warning than the B+M dynamo rear on its own although they can get blocked when cycle touring. I clip them on my luggage then.
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mattsccm
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Re: Rear dynamo lights

Post by mattsccm »

Thanks to those who read my question.
I asked about flashers as I know they do the job I want.
Going dynamo as they remove the need to change batteries or recharge so not interested in a back up. Been using them for 40 years +
Ah well.
rjb
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Re: Rear dynamo lights

Post by rjb »

i have a flasher on my tandem. its a diy set up using a single led front and a 1/2 watt flasher on the rear. (similar to the smart rear flashing lights) The front light is powered by a simple bridge rectifier. (4 diodes and a smoothing capacitor.) The rear is connected in parallel with the front, wires run to the battery terminals on the rear and comes on whenever the dynohub is running. (no batteries in the rear). The smoothing capacitor is a high value 1Farad and will keep the rear flashing for 10 mins after i stop. The system runs at 3.2 volts. :wink:
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
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mjr
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Re: Rear dynamo lights

Post by mjr »

mattsccm wrote: 28 Sep 2022, 10:21am Thanks to those who read my question.
I asked about flashers as I know they do the job I want.
Going dynamo as they remove the need to change batteries or recharge so not interested in a back up. Been using them for 40 years +
Ah well.
A steady light will also "tell a driver that there is something to be aware of". If that's not the job you want, maybe it would be good to say what that job is and others may suggest something less harmful than flashers.

On last night's group ride, I had to be a bit careful to ride behind other dynamo users because it seems this year's cheap flashing rear lights are even brighter than before and utterly destroy your night vision. Even though they don't seem bright enough to dazzle (which would be illegal), I suspect they're now bright enough to reduce rider safety because I don't understand why they won't also destroy the night vision of motorists approaching from behind. The point of light feels far brighter than dipped car headlights now. Maybe the lights will become less obnoxious if the electronics adapt when the batteries become unable to charge to full capacity, or maybe the riders will learn to set them on "sparkle" mode if they have them (where one of multiple LEDs is always lit).
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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MikeF
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Re: Rear dynamo lights

Post by MikeF »

I would have thought a flashing rear light powered by a "dynamo" would cause the front light to flicker as well.
"It takes a genius to spot the obvious" - my old physics master.
I don't peddle bikes.
Jdsk
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Re: Rear dynamo lights

Post by Jdsk »

MikeF wrote: 29 Sep 2022, 9:57pm I would have thought a flashing rear light powered by a "dynamo" would cause the front light to flicker as well.
There are circuit designs that could avoid that.

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rjb
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Re: Rear dynamo lights

Post by rjb »

On my tandem the front light pulses in sync with the rear flashing but only when stationary. When riding the cogging effect of the dynohub causes the front to pulse at low speed but then fully lights with no flicker as speed picks up. :wink:
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
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