get a standlight circuit. Or wear a helmet light

the modern high power LED are well matched to dyno power because you don't need a regulator. The dyno will not put out more current than the LED can handle. The circuits at the link above have more complexity depending on the speed you want to produce light. If low speed light production is an issue, a voltage doubler is used. Since this can cut down on the light at high speed, there are switching circuits to pull the doubler out at a certain speed.

With LED lights at least, adding a battery adds considerable complexity since they can put too much current through the emitter. Similarly with a incandescent dyno to battery conversion, you have to worry about over-driving the bulbs.


I'm moving this to electronics and gadgets