On 2018-02-09 11:40, Ian Field wrote:


"Joerg" wrote in message
...
On 2018-02-08 16:01, Frank Krygowski wrote:
On Thursday, February 8, 2018 at 4:14:47 PM UTC-5, Joerg wrote:
On 2018-02-08 12:20, AMuzi wrote:
On 2/8/2018 2:08 PM, Joerg wrote:


Those 2.4W bulbs were a joke. My bikes (after my teenage
years) always had better lighting than that. Now it's all
LED on my bikes but the real stuff with more than 500 lumens.


For years with a Margil cover or, after a Krygowski mod with O
ring, and
without a switch (always on) I have no complaints about function or
longevity. YMMV.


How much does that O-ring reduce the drag? In the old days (with a real
power bus on the bike) I often rode the first miles with the dynamo off
because of the drag. I only put it back to the wheel when the "steam
gauge needle" (remember those?) got too close to the red range.

First, the terrors of dyno drag are mostly a myth. This article deals
with it:
http://www.myra-simon.com/bike/dynotest.html
"the slowing down has more to do with psychology than the actual
power required
to turn it."
and
"All of the generators were easier to turn than riding up a 1 in 300
slope.
Another way of putting that is a rise of 18 feet per mile; and
there's quite a
cluster of sidewall and hub-driven models around the 1/500 line, or
10 ft per
mile."


Well, take another look at your link. I routinely ride at 30km/h at
which bottle dynamos waste 15W or more. That is nothing to sneeze at.

Bottle dynamos also tend to slip if wet or muddy.


On my MTB it wold be quite useless. On the road bike I could use in just
while not slippery. It has a large battery so 4h no-charge wouldn't be a
problem.

--
Regards, Joerg

http://www.analogconsultants.com/