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anidel
@jj72
I can’t see it working. To fit it inside a standard BB you’d need tiny magnets and too few segments in the commutator which wouldn’t induce much current for one thing, but the real problem would be the speed which the unit would turn. 60 or so rpm would produce bugger-all output. It’s why the old-school SA Dynohub was so weak on anything other than 20” wheels - 27” wheels just didn’t generate enough power. Smaller wheels spin faster which is why dynamos work well on Brommies etc.
Personally I don’t think they’re worth the hassle. USB rechargeable lights are so powerful and simple these days, I’d rather just stick with those.