On Tuesday, May 8, 2018 at 2:32:57 AM UTC+1, Jeff Liebermann wrote:
On Mon, 7 May 2018 14:44:34 -0700 (PDT), Andre Jute wrote:
https://swhs.home.xs4all.nl/fiets/tests/verlichting_analyse/dynamos/vergelijking/index_en.html
https://swhs.home.xs4all.nl/fiets/tests/verlichting_analyse/dynamos/dynamos.gif
At 16 km/hr these deliver 3.5 to 4.5 watts, which seems rather high.

Mmm. I measured the hub dynamo in the Shimano Di2 "Smover" full auto group, admittedly a hub dynamo tuned to power not only the lamps but also the sensors and controller unit, plus the switching units for the full-auto gearbox and the electronically active suspension as well. It produced 3.6W at 6kph (1) and 4.8W at 25kph, after which the line flattened sharply; that's a notable performance for a hub dynamo from around the turn of the century that seemed no bigger than the standard top-end dynamo hub then, Shimano's 3DH72.

(1) This is what I meant when I said that in comparison to the slow SON, the Shimano spun up useful lamp output from only a little over walking, keep-your-balance pace.

AJ
Constant load, calmly