Originally Posted by
steelbikeguy
Sinewave makes a reliable device for this purpose.
https://www.sinewavecycles.com/
There are other sources for this sort of thing too.
There's no reason a person couldn't cobble together a reasonable version of this too. The basics would include a bridge rectifier, filter caps, and a 7805 5V linear regulator. Of course, when the battery is fully charged, the dynamo voltage will rise quite a bit, and some sort of voltage clamp will be needed to protect the 7805.
Steve in Peoria
$120, yike.
You could probably cobble something together with a rectifier, some caps and a buck converter.
A 7805 is very good a providing at reliable supply, but they're not at all efficient. Any excess voltage simply goes into heating the regulator.
You can buy buck converters for about $5 or you can get custom circuit boards fabricated for about $20 (for 10 boards including shipping), so you can affordably do a full custom if you want.
I've given up even bothering with proto boards anymore. I do a basic test of critical things on a breadboard then straight to a custom PCB. There's usually a mistake somewhere, so it costs me a little more, but the final product is better.