Originally Posted by
rifraf
I decided to try to see if my Sturmey GH6 would in any way wake up the Edelux headlight.
I didnt have much faith as the GH6 was reputed to be around 1.8 watts.
Well happy to report it worked fine.
So well in fact that if I hadnt already bought the Son dynamo hub, I'd likely not have bothered.
I'm glad I did, not so much because its likely the Son offers more output or perhaps less drag...
A GB-based tester found his old 6V Dynohub, rated at 1.8W output, drew 1.0W unloaded and 2.6W powering a 1.5W lamp - competitive efficiency with today offerings, and too little drag in either case to be detectable by the rider. Fed into the best of today's LEDs, one can make useful light. They're still heavy, though!
Back to my original comment, the 6V Dynohubs have fewer poles than today's generator hubs and tend to flicker (26-28" wheels) with LED lights without a battery in the circuit to smooth the power. Sturmey also made 8V and 12V Dynohubs.