On 9/12/2017 3:50 AM, sms wrote:
On 9/11/2017 11:59 PM, Sepp Ruf wrote:

snip

For Rob who might experience mental drag uphill from just having to see a
big, heavy, non-laminated hub slowly revolving in the front wheel, the
smallish Shimano DH-T780-1N, 1.5W 250mA class, might suffice[1] once he
grows sick of the Soubitez.* Best price I see is 96 euros a pair from CNC
Hamburg on ebay, no overseas shipping available, though.
http://www.ebay.com/itm/253093811841

[1]
DRL does not require more than 100 lumens if you get the optics right.

True, but if you want a dynamo light for more than just a DRL then that
won't do.

I have an SP dynamo (relabeled as "Joule") on a 20" wheel on a Dahon.
It's coupled to a European dynamo light with about the best optics
available, but at a claimed 200 lumens it's still really only useful as
a DRL, plus it does not have a flash function.

I should add, that I've designed a hack to add modulated capability to
all these European-standard dynamo lights that lack it.

Since when dynamo power is cut off the standlight comes on at lower
brightness, by interrupting the AC power to the light you can modulate
the intensity. Using a magnetic reed switch with a wheel magnet is the
simplest solution but the flash rate varies with wheel speed. Using a
Triac with a timer is a better solution but it needs DC power for the
timer so it gets more complex.

If there were much of a market for dynamo lights in countries where
flashing DRLs are not illegal, then the manufacturers might consider
including modulated DRL functionality.

The only dynamo light I've seen with a DRL flash function is the Planet
Bike Blaze Dynamo SL, which has been improved slightly over the original
and is now rated at 150 lumens. Nashbar has it for $42.18 right now (26%
discount). Once you give up on the idea that ANY dynamo light is going
to be sufficient for commuting, and accept that it's only going to be
useful as a DRL, the Planet Bike light is a pretty good deal. But it
won't work with the 1.5W Shimano dynamo, it needs a 2.4-3.0W dynamo.