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Old March 8th 17, 06:45 PM posted to rec.bicycles.tech
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On 3/6/2017 9:22 AM, Jeff Liebermann wrote:

Kinda looks like all of them will sorta deliver 2.5 watts before the
core saturates (to provide some level of voltage regulation). Further
down the page is a "Low Speed Power" graph, which shows that most can
produce 2.0-2.5 watts at 10km/hr. One could assume that the dynamo
will deliver 4.0 watts, but that would require buying one of the few
better (hub) dynamos listed, and riding at 25-30km/hr (15-19mph).

If I were designing or sizing a lighting system suitable for my slow
style of "cruising", I would use the worst case 10km/hr (6mph) and 2.0
watt figures.


You've touched on one of the reasons why dynamo lights haven't caught on
in the U.S..

I wish that it were possible for inexpensive, dynamo powered lights to
provide adequate illumination for commuting, but it isn't. I recognize
that few people can afford nearly $500 for a hub dynamo wheel and a
SuperNova E3 Triple 2. For commuting, where there is no problem
charging batteries every night, a high power LED set-up is more
economical and provides better illumination. It's hard enough getting
people to spend even $25 on a bicycle light, getting them fork out $500
for a dynamo wheel and a decent dynamo light would be damn near impossible.

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