So I’m about to build a couple of dynamo wheels primarily to charge a power bank and keeping phone topped up. Then I thought, could I make a light out of an old Chinese job that I’ve got lying about. Would be perfect if I could also incorporate a small battery so it had a standlight.

Realistically is this doable if you havnt got the first clue about electronics? Anyone tried anything similar and been successful or set fire to stuff?

I did change the emitter in my fluxient U2mini for a whiter light so not a total biff!!

Yes you can.  somewhere ( candlepower forums?) I have seen a circuit to run an led straight from the dynamo or you could use the dynamo to charge a battery pack and run the light off that.  The issue you will have is you only have 3w to play with which might not be enough for the light you have.  If its for road use I would just use a B+M light – so much better than MTB type lights for road use.

I reckon it will be more expensive in time and money to adapt an existing light instead of just buying a dynamo specific light.

I ran a led directly from a dynohub just running through a bridge rectifier, a cap would smooth things out but I found once above walking pace it was fine.

If you are converting a battery led I would make sure there is a small battery in line and run it also through a switch mode power supply chip. Standard application circuits will be on data sheet. Just copy one of those.