"John Larkin" wrote in message
...
On Sun, 04 Dec 2011 09:23:12 -0700, Jim Thompson
wrote:

On Wed, 30 Nov 2011 13:09:54 -0700, Jim Thompson
wrote:

On Sun, 27 Nov 2011 14:56:00 -0000, "Ian Field"
wrote:

Tinkering with the old Sturmey archer bicycle dynamo, I was wondering
whether it would charge a 1.2Ah SLA any better if the loading was
modified.

The generator is rated 6V/3W, but off load at a decent rate of knots it
can
produce over a couple of hundred volts.

What I was wondering was whether its possible to get more energy into
the
battery by letting the generator output voltage stretch its legs so to
speak
and convert the excessive voltage down with a buck converter.

Can anyone advise on the practicality of this please?

Thanks.


Bwahahahahaha! So this was the original post? Bwahahahahaha!

...Jim Thompson

Perhaps Larkin would be happy to address Ian's question, "What I was
wondering was whether its possible to get more energy into the battery
by letting the generator output voltage stretch its legs so to speak
and convert the excessive voltage down with a buck converter"?


Well its what I wanted to hear anyway, I might start thinking about a design
for a buck converter to try it out and see what happens, might be possible
to get away with a MC34063 - failing that maybe a discrete component design.

Unfortunately my workshop has been dismantled for refurbishing and most of
the stuff crammed into the shed - so no room to work in there either.

When I tried LTspice I found it a PITA to use - maybe while deprived of my
workshop I should give it another chance.