I have no scope, but there are no major symptoms of anything amiss, electrically. There can be as few as nine components in the circuit, including the switch and the rear light parts. I expect to be showing a (flickery) light front and rear even at a walking pace. It will have a (different) low loss rectifier and will be built round some LEDs I have found which have a low forward voltage of ~2.45V 100mA.

I have in mind a design that has lower losses in the rectifier, and automatically switches from paralell to series operation with speed.īut right now I'm building a simpler (no standlight), cheaper front light which is intended to make the most of the feeble output of an SA dynohub. It is worth measuring the current/volts actually going through the LEDs and comparing this with the current/volts at the generator a lot of these circuits can be really lossy this makes for a light that isn't as bright and/or a light that doesn't come on at low speeds. If you have a 'scope it is worth testing the circuit to see that it is working properly. My suspicion is that if the light is flickery at speed, maybe there is a fault in the circuit as built. I wonder if an auxiliary box isn't a bad idea here you could keep all the electronics in one place then, and just have simple/compact lights with little more than the LEDs in.

It is a shame you have started with such a small housing to work with. If anyone has any questions/suggestions, chime in! The other components I'm only partially counting, as I still have spares of those. There are still a few niggles, so I'll ride it a bit more, and then diagnose problems/think of improvements. The Pico still has better graduated road illumination. That LED also lights up first in the circuit (I presume when there's not enough voltage for both LEDs, current flows down the diode towards the supercap, and is then shared between the supercap and LED2), so that actually helps low speed illumination. The circuit dictates that only one light ('LED 2') will be lit by the standlight, but that's no biggie. That was one of the most expensive components though. With a 1.5F supercap (just about fits in there) it's at least as good as the one on my Pico - bright for about 3 minutes, then fading for the next 10 minutes. I think it may have flickered less until I hit a big bump, which might have knocked off the capacitor. Testing it today, it works! Unfortunately I couldn't fit a smoothing capacitor larger than 470uF, which is too small to do any real smoothing, so the thing still flickers under 15km/h. The dynamo circuit - extremely tight cram! I lined most parts which could short out with electrical tape.

Space plan generator dynamo