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  #27  
Old May 6th 18, 11:15 PM posted to rec.bicycles.tech
James[_8_]
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Posts: 6,153
Default Dynamo/LED power conditioning

On 07/05/18 03:01, Joerg wrote:


Note the three big 470uF capacitor in the schematic. That's the "flicker
reduction trick" :-)

Problem is, electrolytic capacitors do not live long in harsh climate
conditions such as the black light enclosure baking in the glistening
Arizona desert sun for hours every week or riding around the Klondike in
a harsh winter.

For me the only proper way of lighting a bicycle is with a rechargeable
battery.


Bull**** alert!

We all know how reliable rechargeable batteries are, especially in harsh
environments, right?

OTOH, here is an electrolytic cap from Vishay, that has a "useful life"
of 1,000,000 hours at 40C, and 8000 hours at 125C.

https://www.vishay.com/docs/28334/118aht.pdf

(The useful life approximately halves for every 10C increase.)

If the temperature inside the electronics enclosure was much more than
80C for most of the time the light is in operation (E.g. while you're
riding and the light has forced air cooling), the engineer ought to be
shot, and that still gives a useful life of over 62500 hours.

--
JS


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