"white" LED's vs. incandescent and halogen lights

"white" LED's vs. incandescent and halogen lights

Post by Frank Krygowsk » Tue, 15 Dec 2009 02:01:50



Quote:

> I'm quite happy w/ my old-school generator + Union headlight,
> supplemented a little with flashlight battery lights.
> It is enough. ...
> The venerable Union headlight still works well because of
> its intelligently designed Fresnel(ish) lens + reflector,
> and the broad disc of light it emits.

> New technology isn't always better technology. ...

> Frankly, when riding at night, I don't even want to
> turn night into day. ...

And I pretty much agree with all the above.  But still, there are
(rare) times I wish my generator lights would give a _little_ more
light.

Which brings me to the question:  How soon before we can buy drop-in
replacement LED bulbs for existing bike headlight generator sets?

These things already exist for flashlights, for car taillights, and
for other applications for which the electrical problems are larger
(i.e. the need to regulate current by at least crude means).  Most
white LEDs will do fine with the regulated 1/2 amp that's naturally
produced by typical bike generators.

There are problems with heat sinking, I suppose.  And there may be
some problems with optics, since LEDs don't emit the same near-
spherical field as a filament.  Some cleverness might be needed to get
the LED to direct its light in the proper direction.

But if those could be solved (or safely ignored?) it seems there's a
ready market.

- Frank Krygowski

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by datakol » Tue, 15 Dec 2009 02:05:21

DAY light is short now. Try shooter's yellow clipons and a second
lamp, of different manufacture, mounted low on the forks.

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Nate Nage » Tue, 15 Dec 2009 02:55:12

Quote:


>> I'm quite happy w/ my old-school generator + Union headlight,
>> supplemented a little with flashlight battery lights.
>> It is enough. ...
>> The venerable Union headlight still works well because of
>> its intelligently designed Fresnel(ish) lens + reflector,
>> and the broad disc of light it emits.

>> New technology isn't always better technology. ...

>> Frankly, when riding at night, I don't even want to
>> turn night into day. ...

> And I pretty much agree with all the above.  But still, there are
> (rare) times I wish my generator lights would give a _little_ more
> light.

> Which brings me to the question:  How soon before we can buy drop-in
> replacement LED bulbs for existing bike headlight generator sets?

> These things already exist for flashlights, for car taillights, and
> for other applications for which the electrical problems are larger
> (i.e. the need to regulate current by at least crude means).  Most
> white LEDs will do fine with the regulated 1/2 amp that's naturally
> produced by typical bike generators.

> There are problems with heat sinking, I suppose.  And there may be
> some problems with optics, since LEDs don't emit the same near-
> spherical field as a filament.  Some cleverness might be needed to get
> the LED to direct its light in the proper direction.

> But if those could be solved (or safely ignored?) it seems there's a
> ready market.

> - Frank Krygowski

I'm still waiting for LED taillight replacements to become acceptable.
They're not there yet, despite the superiority of LED flashlights and
bicycle headlights.  I've tried several, mostly because I've been trying
to avoid having to custom make taillight LED boards and/or cut up some
expensive truck taillights for my '55 Studebaker (the stock taillights
with 1034 or 1157 bulbs are just not as bright as one would expect a car
tallight to be, and they have plastic lenses so I'm not perfectly
comfortable using halogen bulbs.)

I had promised to see if a Mag-Lite LED "bulb" would fit in a Lumotec,
and I never did check.  I have located my Mag-Lite; unfortunately, it
happens to be in the trunk of my car and it's 35 degrees and raining at
the moment, making it yet another Sunday in a long string of Sundays
where I was hoping to be able to go for a nice ride, and have looked
outside as soon as the sun came up and said "Oh, HELL no."

nate

(who apparently needs to invest in some full length tights, full finger
gloves, and shoe covers if he's going to get back on the bike any time
soon...)
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"white" LED's vs. incandescent and halogen lights

Post by somebod » Tue, 15 Dec 2009 10:56:33



Quote:


>>> I'm quite happy w/ my old-school generator + Union headlight,
>>> supplemented a little with flashlight battery lights.
>>> It is enough. ...
>>> The venerable Union headlight still works well because of
>>> its intelligently designed Fresnel(ish) lens + reflector,
>>> and the broad disc of light it emits.

>>> New technology isn't always better technology. ...

>>> Frankly, when riding at night, I don't even want to
>>> turn night into day. ...

>> And I pretty much agree with all the above.  But still, there are
>> (rare) times I wish my generator lights would give a _little_ more
>> light.

>> Which brings me to the question:  How soon before we can buy drop-in
>> replacement LED bulbs for existing bike headlight generator sets?

>> These things already exist for flashlights, for car taillights, and
>> for other applications for which the electrical problems are larger
>> (i.e. the need to regulate current by at least crude means).  Most
>> white LEDs will do fine with the regulated 1/2 amp that's naturally
>> produced by typical bike generators.

>> There are problems with heat sinking, I suppose.  And there may be
>> some problems with optics, since LEDs don't emit the same near-
>> spherical field as a filament.  Some cleverness might be needed to get
>> the LED to direct its light in the proper direction.

>> But if those could be solved (or safely ignored?) it seems there's a
>> ready market.

>> - Frank Krygowski

>I'm still waiting for LED taillight replacements to become acceptable.
>They're not there yet, despite the superiority of LED flashlights and
>bicycle headlights.  I've tried several, mostly because I've been trying
>to avoid having to custom make taillight LED boards and/or cut up some
>expensive truck taillights for my '55 Studebaker (the stock taillights
>with 1034 or 1157 bulbs are just not as bright as one would expect a car
>tallight to be, and they have plastic lenses so I'm not perfectly
>comfortable using halogen bulbs.)

There are already LED replacements for brake lights.  Check
http://www.dealextreme.com/products.dx/category.708

For bicycle use I went with a 3 watt red Luxeon with one of the DX
switching regulators and mounted it in a cheap trailer taillight.  I
also tried a 1 watt version using a cheap bike taillight as a housing,
wasn't bright enough for me.

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Frank Krygowsk » Tue, 15 Dec 2009 15:07:45

On Dec 13, 8:24?pm, Phil W Lee <phil(at)lee-family(dot)me(dot)uk>

Quote:

> 09:01:50 -0800 (PST) the perfect time to write:

> >Which brings me to the question: ?How soon before we can buy drop-in
> >replacement LED bulbs for existing bike headlight generator sets?

> >These things already exist for flashlights, for car taillights, and
> >for other applications for which the electrical problems are larger
> >(i.e. the need to regulate current by at least crude means). ?Most
> >white LEDs will do fine with the regulated 1/2 amp that's naturally
> >produced by typical bike generators.

> All those are already DC.
> Cycle generators are AC.
> So your drop in replacement is going to need to rectify (and possibly
> smooth) the power.

With two LEDs arranged anti-parallel, you don't need to rectify.  At
least, that's what my bench testing (and a expert consultant's
opinion) have told me.  That can be done within one unit (i.e. one
"bulb").

Quote:
> >There are problems with heat sinking, I suppose. ?And there may be
> >some problems with optics, since LEDs don't emit the same near-
> >spherical field as a filament. ?Some cleverness might be needed to get
> >the LED to direct its light in the proper direction.

> So now the "drop in" replacement is going to need new optics as well.

No, that's not what I meant.  I'm talking about having an LED package
that would do an acceptable job of using the existing optics of a
decent, stock generator headlamp.  It would probably require only
minor modifications of the LED package itself.

Quote:
> Why not just get a replacement light unit?

Cost.  A decent LED generator headlamp goes for $40 or more.  Most of
the bikes in Europe already have decent generator headlamps, including
pretty good reflectors and lenses.  An LED replacement for their
halogen or vacuum bulbs seems like a no brainer.

Standard generator bulbs burn out in, oh, 150 hours or so.  It's not
terrible, it's acceptable life; but if you could offer them an upscale
replacement, a $10 dual LED bulb that put out 50% more lumens, would
last forever, and was still adequately focused by their original
reflector and lens, I'd think it would sell.  I'd certainly buy five
of them.

And note, it wouldn't need to be a top-drawer LED with absolute
maximum lumens per watt.  It would merely need to significantly beat
typical halogen bulbs.

It sounds like a job for Reflectalite.

- Frank Krygowski

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Chal » Tue, 15 Dec 2009 17:56:37

Quote:

> With two LEDs arranged anti-parallel, you don't need to rectify. ?At
> least, that's what my bench testing (and a expert consultant's
> opinion) have told me. ?

According to technical materials for Lumileds' Luxeon LEDs, white (and
blue, green, cyan, NUV) emitters are robust enough to reverse voltage
to be effectively used in anti-parallel configuration, but red and
amber emitters are not.  (I don't know whether the same goes for other
high-flux LEDs like Cree or Seoul Semiconductor.)

I accommodated this limitation by wiring two series of one white and
one red emitter each in anti-parallel configuration.  The white LEDs
block any reverse current flow that might damage the red ones.

Chalo

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Dave Larringto » Tue, 15 Dec 2009 18:54:27



Quote:
> Most of this has been done already.  Why try to reinvent the wheel?
> Comparing LEDs with halogens for bike lights, the current LEDS have
> already surpassed halogens and will continue to improve.  Halogens
> are a mature technology and unlikely to improve significantly in this
> application.

> The photos are on the Web already.  Google around.  Start with Peter
> White Cycles; Peter has posted quite a few comparison photos.

See also:

http://picasaweb.google.co.uk/grahamglen0/LightTesting#

--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk>
A complimentary biro(tm) is /not/ to be sniffed at.

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Autymn D. C » Tue, 15 Dec 2009 19:55:22


Quote:


> > There seems to be a mindset that that is indeed what
> > bike riders need to do, either in terms of o/p wattage
> > or brightness. ?In city traffic, blinking lights + speed
> > difference + positioning on the street does the trick
> > nicely -- as long as the batteries don't fade.

Post at nesci.physics instead then.

Quote:
> So get a lead-acid battery from a motor-cycle.
> The weight won't affect your speed, just your acceleration,
> and when you get tired pedalling you can run a motor from
> it. Electrically propelled bicycles have been around for a while
> now.
> Anyway, bikes are faster than cars in city traffic which is why
> couriers use them.

Weiht affects both, and bikes are freer than cars, not faster.
 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Nate Nage » Tue, 15 Dec 2009 20:40:34

Quote:





>>>> I'm quite happy w/ my old-school generator + Union headlight,
>>>> supplemented a little with flashlight battery lights.
>>>> It is enough. ...
>>>> The venerable Union headlight still works well because of
>>>> its intelligently designed Fresnel(ish) lens + reflector,
>>>> and the broad disc of light it emits.

>>>> New technology isn't always better technology. ...

>>>> Frankly, when riding at night, I don't even want to
>>>> turn night into day. ...
>>> And I pretty much agree with all the above.  But still, there are
>>> (rare) times I wish my generator lights would give a _little_ more
>>> light.

>>> Which brings me to the question:  How soon before we can buy drop-in
>>> replacement LED bulbs for existing bike headlight generator sets?

>>> These things already exist for flashlights, for car taillights, and
>>> for other applications for which the electrical problems are larger
>>> (i.e. the need to regulate current by at least crude means).  Most
>>> white LEDs will do fine with the regulated 1/2 amp that's naturally
>>> produced by typical bike generators.

>>> There are problems with heat sinking, I suppose.  And there may be
>>> some problems with optics, since LEDs don't emit the same near-
>>> spherical field as a filament.  Some cleverness might be needed to get
>>> the LED to direct its light in the proper direction.

>>> But if those could be solved (or safely ignored?) it seems there's a
>>> ready market.

>>> - Frank Krygowski
>> I'm still waiting for LED taillight replacements to become acceptable.
>> They're not there yet, despite the superiority of LED flashlights and
>> bicycle headlights.  I've tried several, mostly because I've been trying
>> to avoid having to custom make taillight LED boards and/or cut up some
>> expensive truck taillights for my '55 Studebaker (the stock taillights
>> with 1034 or 1157 bulbs are just not as bright as one would expect a car
>> tallight to be, and they have  plastic lenses so I'm not perfectly
>> comfortable using halogen bulbs.)

> There are already LED replacements for brake lights.  Check
> http://www.dealextreme.com/products.dx/category.708

I know this, my point was that there aren't any *good* ones or even
"acceptable" ones available.  I keep trying them every 2-3 years hoping
that they're good enough yet but am always disappointed.

nate

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replace "roosters" with "cox" to reply.
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