"josephkk" wrote in message
...
On Tue, 17 Jan 2012 21:48:22 -0000, "Ian Field"
wrote:


"Nico Coesel" wrote in message
...
John Larkin wrote:

On Tue, 17 Jan 2012 12:49:23 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
m...

Here you go...

http://analog-innovations.com/SED/Bi...ubSwitcher.pdf

[snip]

Anyone care to actually discuss this?

Paul
www.pstech-inc.com


If led's are so efficient that a couple of watts is enough, there's no
need to multiply the alternator current. No switcher, no transformer.
A rechargable battery is a nice idea, to have lighting when you're
going slow or stopped. Simple linear electronics is probably all you
need.

The tail light of my 15 year old bicycle uses a supercap to store
energy. It has enough storage to keep the led on for about a minute
after stopping. Ofcourse the tail light doesn't need to be very
bright.

I'd like to replace the front lamp with a led lamp though.


I bet whatever 'dynamo' you have is better than my old Sturmey archer AG
hub
which would only shift 1.8W loaded by the specified bulbs.

Currently I use it to charge a 1.2Ah SLA battery which powers a pair of
current sensing flyback converters that feed to series chains of LEDs, my
design was published in Elektor a few years ago.

The subject of my post on SED that triggered this thread here by JT was a
request on whether better load matching an old SA 'dynamo' could squeeze
more power from it - the consencus seems to be yes.

My read on that is more of a maybe, let's try it.

The extra power going into the battery would be handy for occasional use of
a 3W star LED "main beam" for unlit sections of cycleway.

Nice recap on what you have and where you want to go. Some others lost
sight of that.

I've lost count how many times I've corrected JT that *I AM* using LEDs -
but he still persists in calling me an "antique" for using bulbs!