Bicycle generators and LED lights

[Luhan]

There have been credible reports that some of them are *fakes* (the
generator part does nothing) and they just run off of primary cells
button cells for a while.

The full size ones actualy work (slightly), the smaller ones just run
off the watch battery for a while.

Luhan

 

[Paul E. Schoen]

The full size ones actualy work (slightly), the smaller ones just run
off the watch battery for a while.

Luhan

This was discussed a while ago in June about my experience with
Shake'n'Fake flashlights I got at the Harpers Ferry flea market. They were
only about $3 each. There is a little PC board in them, and one of them had
a resistor on it, but the wires from the coil were not even connected.
Others had the wires twisted together and stuck into a hole on the board,
and the "magnet" was just a slug of steel.

I actually replaced the slug with a magnet from an old meter, and I wired
up a little circuit with a 1N34 diode, a capacitor, and an LED, to see if
any useable voltage would be generated. After I shook it for awhile, I
measured the voltage on the capacitor, and sometimes found several hundred
millivolts. However, I discovered that it was just coming from the battery
through my hand.

The coil was only about 40 turns of fine wire. I wonder how many turns are
needed, or how fast the magnet must move, and how strong the magnet needs
to be, in order to generate enough voltage and current to light the LED.
There are some real ones for sale, but they cost about $20 or so, and I
heard that you can actually feel the magnet slowing down as it generates
power.

The lights I bought have a clear case, which seems like a cool idea so you
can see the mechanism, but actually it produces glare which makes it less
effective.

At the same flea market, I bought a couple of hand cranked lights, which
seem to work properly, although the mechanism will probably wear out if it
is used very much. They were about $5 each. Maybe they could be attached to
the handlebars and the counterforce from pedaling could be used to pump a
pair of them.

Paul

 

[Jim Yanik]

Here is the supplier...

http://stores.ebay.com/HKJE-Led-Lamp-Center

Luhan

THANKS!

 

[Jim Yanik]

The full size ones actualy work (slightly), the smaller ones just run
off the watch battery for a while.

Luhan

The shaker I had did not even have the coil connected,the wires were just
hid under the lower battery contact,both of them still twisted together.
It had a CR2032 and a CR2025 cell in series.The "magnet" was just plain
unmagnetized soft iron.

It only cost me $3 at a "dollar" store,no great loss.

 

[Johnny Sunset aka Tom Sherman]

...
3. The Sturmey-Archer dyno hub. I haven't personally used it, but it
puts the generator inside the front hub of the wheel. I have a close
cousin and friend who _does_ have experience with them, and he speaks
highly of them. They're hard to get in the US (if S-A even makes them
any more). It's supposed to be very reliable -- the construction
certainly _sounds_ bullet proof -- but there's a bit of a weight penalty.

All of these methods suffer from the simple problem that when you stop
the light goes out. So you have your choice of inefficient, more
efficient but hard to get and breaks, or quite efficient but heavy and
unobtainable....

Why bother with the obsolete Sturmey-Archer Dynohub?

Harris Cyclery imports Shimano dynamo hubs that are better in every way
than the old Sturmey-Archer:
<http://sheldonbrown.com/harris/lighting/shimano.html>.

The premium quality (and most expensive) dynamo hub is the Schmidt's
Original Nabendynamo (SON) hub:
<http://www.peterwhitecycles.com/schmidt.asp>.

A wide range of lights, both halogen and LED are available, and many
include a standby capacitor so the headlight will remain lit for a
couple of minutes when stopped (long enough for most traffic signal to
complete a cycle).

 

[Richard B]

I got them on Ebay. 50 for 99 cents plus $18 'shipping'. Thats
basically 50 for $20. They are 10mm (big) and have a 10 degree angle,
which runs up the mcd spec. I also bought 50 UV LEDs for $10 plus
free shipping - they work great too.

Luhan

Here are a couple of websites that will provide more than you want to
know about LED technology.

http://ledmuseum.home.att.net/ledleft.htm
http://electronics.howstuffworks.com/led.htm

And while you are at it try looking at http://pocketlites.com/
You may be able to find something there that you can use or modify to
suit your needs.

Rich

 

[René]

Slightly puzzled with this thread...

Here in Holland (were we cycle a lot!) one can find battery operated
headlamps / taillights in enormous numbers in a variety of shops.
Cheap too. Which is nice - because my kids seem to incur a lot of wear
to their bikes and lighting options mounted thereon. Leds are nice to
be visible to other traffic, but if you need to light your own path
(dark roads outside town) halogen is a lot better. (less hi-tek then
luxeon stars etc, but a *lot* cheaper)

Why bother with dynamo's? Just buy a few sets of NiMH AA's, a cheap
1/10C charger, and you are set for the dark winter. Most lights are
quick-removable and serve as hand-torch if needed.

Al in all works a lot better than the conventional slipping dynamo +
broken wires / bulbs I had to live with in my youth.

 

[Tim McNamara]

Why bother with dynamo's? Just buy a few sets of NiMH AA's, a cheap
1/10C charger, and you are set for the dark winter. Most lights are
quick-removable and serve as hand-torch if needed.

Al in all works a lot better than the conventional slipping dynamo +
broken wires / bulbs I had to live with in my youth.

It depends on your needs. I ride brevets which can involve riding
literally from dusk till dawn, and there aren't any battery powered
lights that will last that long. I'd either have to have multiple
lights or carry spare batteries. Rechargeable lights are nice, as long
as you are sure you'll have enough time between rides to recharge them.
If all I needed was light up to an hour or so once a day, then I'd
probably find a battery powered light to be all I needed.

With a generator system, the light is always there, ready to go. You
don;t have to think about it at all. Generators and headlamps have
improved quite a bit, as well. Hub generators such as the Schmidt SON
or the Shimano units are very reliable and have negligible drag. I have
the Schmidt on one bike, and a Sanyo Dynapower bottom bracket mounted
generator on another. And battery powered lights for a third bike that
is used mainly for riding to and from work.

 

[Luhan]

Here are a couple of websites that will provide more than you want to
know about LED technology.

http://ledmuseum.home.att.net/ledleft.htm
http://electronics.howstuffworks.com/led.htm

And while you are at it try looking at http://pocketlites.com/
You may be able to find something there that you can use or modify to
suit your needs.

Rich

Thank you soooo much. That information on copulation was very
helpful....


Luhan

 

[Donald]

Thank you soooo much. That information on copulation was very
helpful....


Luhan

WHAT !!!

http://dictionary.reference.com/browse/copulation

 

[Luhan]

WHAT !!!

http://dictionary.reference.com/browse/copulation

Here is some of what shows up at pocketlites.com

http://members.cox.net/berniekm/poketlites.jpg

Luhan

 

[Donald]

Here is some of what shows up at pocketlites.com

http://members.cox.net/berniekm/poketlites.jpg

Luhan

I guess thats the problem, this site comes up blank for me.

so, I don't get it.

 

[Richard B]

Here is some of what shows up at pocketlites.com

http://members.cox.net/berniekm/poketlites.jpg

Luhan

I see I typed pocketLITES.com but I meant pocketLIGHTS.com.

But even the mis-entered "pocketlites.com" link is not a porn site.

Your JPEG says pOKEtlites not pOCKtlites, did you typo?
Perhaps one or more of the links on the mis-entered pocketlites page was
hijacked...

Try this...
http://tinyurl.com/pj2un
I used tiny url to shorten the pocketlights.com link and I tested it.
Maybe it will work for you now.

Pocketlights.com is a website that sells all kinds of high tech lighting
solutions.


Rich

 

[[email protected]]

For my bike (nothing special, a nice simple road bike bought at a
garage sale) I would like to add a bicycle generator and LED lights.

I assume that output voltage of these generators varies with
speed. There are some on sale on ebay for not too much, 6v or 12v
models, most are 6 watts.

I want to do it in some nice way, such that

1) the LEDs would work across the range of speeds and be protected
from overvoltages and such

2) Most power would not be lost on some current limiting resistors,
but instead would go into LEDs. I think that 6W spent on LEDs would
give me a lot of light.

If there are products like that on the market already, I do not want
to "reinvent the wheel" and I would rather buy one, but I am not sure
if such a thing is available.

I would prefer LEDs to regular incandescent bulbs for many very
obvious reasons (more light and more reliability).

I am moderately handy and built some electronic things before, like a
control and inverter for a DC welder.

Any ideas?

i

Generator, try the sports section at your local Target.

Michael

 

[John Woodgate]

Try this...
http://tinyurl.com/pj2un
I used tiny url to shorten the pocketlights.com link and I tested it.
Maybe it will work for you now.

Pocketlights.com is a website that sells all kinds of high tech
lighting solutions.

KinkEEEE!(;-)

 

[James F. Mayer]

I see I typed pocketLITES.com but I meant pocketLIGHTS.com.

But even the mis-entered "pocketlites.com" link is not a porn site.

Your JPEG says pOKEtlites not pOCKtlites, did you typo?
Perhaps one or more of the links on the mis-entered pocketlites page was
hijacked...

Try this...
http://tinyurl.com/pj2un
I used tiny url to shorten the pocketlights.com link and I tested it.
Maybe it will work for you now.

Pocketlights.com is a website that sells all kinds of high tech lighting
solutions.


Rich

Anybody tried http://www.sunbriteleds.com/index.asp ? They have led
incandescent lamp replacements and available from Digikey.

 

[jtaylor]

2. A generator inside a wheel that runs on the tire tread. These are
much lower drag than (1), but the ones I've seen mount on the
intersection of the chain stays with the bottom bracket, and they don't
last long. They're also not easy to come by.

If the one you are referring to is the Sanyo dynamo, there is a design
problem which leads to early falure - that can be fixed...

The operating cam is fixed to its lever by a hex-shaped hole; this hole
wears on the matching section of the shaft. It can be fixed by carefuly
excising a portion of the aluminium casting and silver-soldering the cam to
the shaft. (The excision is required to get access to the shaft/cam with
your torch flame.)

 

[Luhan]

I see I typed pocketLITES.com but I meant pocketLIGHTS.com.

But even the mis-entered "pocketlites.com" link is not a porn site.

Thats just what I typed in for the filename; it could have been
anything.

Looks like link to a porn site to me.

Luhan

 

[Luhan]

I see I typed pocketLITES.com but I meant pocketLIGHTS.com.

But even the mis-entered "pocketlites.com" link is not a porn site.

Your JPEG says pOKEtlites not pOCKtlites, did you typo?
Perhaps one or more of the links on the mis-entered pocketlites page was
hijacked...

Try this...
http://tinyurl.com/pj2un
I used tiny url to shorten the pocketlights.com link and I tested it.
Maybe it will work for you now.

Pocketlights.com is a website that sells all kinds of high tech lighting
solutions.


Rich

Those flashlights seem way overpriced. I have a couple nice ones that
I got for $5 each at the local flea market.

Luhan

 

[joseph2k]

I have a 6 volt, 4 amp hour gel cell on my bike along with a set of 8,
125,000 mcd white LEDs. The total draw is about 200ma, and I only need
to rechage the battery once a month.

Luhan

So how big is the battery?