Schmidt hub dynamo : any "add ons"?

I use a rectifier from a 9V 1A dc power adapter similar to the ones that come with cordless phones
etc... Use the small board inside with the capacitor and connect the schmidt in place of the
transformer connection (AC). You could use a DC voltage regulator on the output or a rechargeable
battery pack to control the voltage. I use 4 AA rechargeable NiMh batteries in a backup light in
parallel with 4 AAA NiMh batteries external that I use for my MP3 player. I have had no problems
with overcharging/overheating the batteries with this setup. The charge voltage for 4 cells is very
close to 6V so it acts as a voltage limiter for your light also. With the light on very little
current will flow to the batteries unless they are totally drained. "Walter Mitty" <[email hidden]> wrote
in message "]news:[email hidden]...

Quoted message said:

Since the Schmidt Original Nabendynamo is so damn efficient (I have one),

I

Quoted message said:

was wondering if anyone in this group might know about transformers/smoothers in order for the
Schmidt to power a portable radio or walkman or even charge a mobile phone while on the road.

I don't think it should be impossible. Should it? Is it done?

--
Walter Mitty.

Walter Mitty <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Since the Schmidt Original Nabendynamo is so damn efficient (I have one), I was wondering if
anyone in this group might know about transformers/smoothers in order for the Schmidt to power a
portable radio or walkman or even charge a mobile phone while on the road.

I don't think it should be impossible. Should it? Is it done?

No idea. You might check on the BikeCurrent list, which is hosted on topica.comtopica.comOpen ↗

I see one problem, however. On top of voltage regulation, you would have to deal with the fact the
Schmidt and other dynamos produce alternating current whereas most chargers and electronic gizmos
need continuous current.

Regards,

Michel Gagnon

[email hidden] (Michel Gagnon) brightened my day with his incisive wit when in
"]news:[email hidden] he conjectured that:

Quoted message said:

Walter Mitty <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Since the Schmidt Original Nabendynamo is so damn efficient (I have one), I was wondering if
anyone in this group might know about transformers/smoothers in order for the Schmidt to power a
portable radio or walkman or even charge a mobile phone while on the road.

I don't think it should be impossible. Should it? Is it done?

No idea. You might check on the BikeCurrent list, which is hosted on topica.comtopica.comOpen ↗

I see one problem, however. On top of voltage regulation, you would have to deal with the fact the
Schmidt and other dynamos produce alternating current whereas most chargers and electronic gizmos
need continuous current.

Regards,

Michel Gagnon

Yeah, but thats what rectifiers & smoothers are for. The other gizmos still nede adapters to plug
into the wall. The schmidt is a lower power wall socket.

--
Walter Mitty.

Walter Mitty said:

Yeah, but thats what rectifiers & smoothers are for. The other gizmos still nede adapters to plug
into the wall. The schmidt is a lower power wall socket.

Hmmmm.. Basically, you'd need to make a flexible AC-DC converter circuit which ends up with the
correct voltage whenever you're going faster than x km/hr. The voltage and wattage a bike generator
is designed for is 6V/3W, or in other words 6V, and .5 A. I've been told that hub dynamos, at least,
pretty much act like a current source, as long as the speeds are there. So you'd need to determine
first how much your cell phone draws when charging. The (non-extra-fast) charger for my Nokia 3310
says it's 3.7 V at 355 mA, or 1.7 VA.. holy [censored], it only draws about half of a standard bike
lighting setup.

Okay, given the low voltages, I think it's probably safe to say that the regulation and smoothing is
gonna take up a fair amount of the power, at least a quarter if not more. I think I'd "Keep It
Simple, Stupid", and just do rectifier > smoothing cap > low drop regulator. The electronics could
easily fit in a small housing attached to a carkit style holder for your phone. You might want to
look at a regulator that switches off when it drops out of regulation, rather than just passing the
lower voltage.

It's not impossible that using this setup, when you're going fast, voltages spat out from the hub
would go up far enough to damage the regulating electronics (not (usually) the phone itself, unless
the regulator shorts, which remains a possibility). I'd be very careful about this stuff and first
try rifing withg a dummy load and a voltmeter in operation, and see what transpires.

Jasper