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I run a SON hub dynamo and have recently upgraded my front light (the old light and the dynamo are ~10 years old). The new one is much brighter than the old and has a USB outlet for charging stuff, so I'm very happy with that (Lumotec Eyc).

What I want from a rear light is something like the "superflash" red LED lights, but any kind of blinking would be acceptable. Ideally I'd like one that has both constant and blinking LEDs but I have enough power available to run two, so I'm willing to keep my existing light.

I run my dyno lights constantly, day and night, so having an "off" switch is not necessary (and slightly undesirable), I'd be quite happy with a light that simply flashes whenever power is applied.

But with much searching I have not been able to find anything. I am specifically not interested in the "reelight" things, they will not work for me (and I recommend against them in general, they flash too slowly and too dimly). This thread on bikeradar didn't turn up anything. I suspect part of the problem is that blinking bike lights are not legal in Germany, home of all the good bike light manufacturers.

But I would love a link to one that I can buy, if anyone has one.

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I concur with the questions unhappy verdict that German law prevents flashing rear dynamo powered lights, Peter White is stronger with his "No." – Samuel Russell Dec 3 '13 at 2:57
Traditionally, blinking taillights have not been provided with gensets because the load of a blinking incandescent lamp would cause the headlight to flicker (worse than it did already). But certainly there have been blinking taillights for battery sets that could be adapted to a genset, and with LEDs the fluctuating load is no longer an issue. (This might actually be a good challenge for some teenager electronics hobbyist -- relatively cheap and straight-forward to do, with readily available parts, other than the housing.) – Daniel R Hicks Dec 3 '13 at 4:09
@DanielRHicks if I was going to DIY I'd most likely take an existing blinky, remove the batteries and add a 3V regulator or DC/DC converter and run it off the front light output, which is usually a smooth-ish 5V or 6V with modern lights. In my case I have 5V 500mA available from the USB output as well. Although given how many spare blinkies I have, I'd be tempted to leave out the converter and see if one would just run off 6V :) In fact, I might just do that when I get home. A lab power supply is just like a dynamo, isn't it? – Mσᶎ Dec 3 '13 at 4:33
@Ӎσᶎ, why not put several in series ;p – Vorac Dec 3 '13 at 9:23
@Ӎσᶎ they probably would run off 6V, most of the blinkies run off 2 lithium coin cells in series, giving ~7V. Might need a capacitor though. Even the bigger rear lights use a driver chip that has a reasonable range of input voltages, to provide their current-controlled output. I'm running the PCB of a 2AA rear light in the battery box of a 3AA head torch which I've modded to use 1 lithium AA. so everything runs of 3.6V. Works a treat. – Chris H Dec 3 '13 at 10:50

1 Answer 1

I have an Origin rear light and I've seen that it can be charged via usb and also have the lights on at the same time. If you want to have it powered by a Dynamo, what you could do is have the Dynamo connected to it the whole time on the bike and be lighting at the same time. That could be a way to pull it off and never have to take it off. Also, if you have daylight, the lights could be off and charging so you can use it when the night comes. Good luck.

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