DIY lighting, MR 11 upgrade, reflector/lens?

In article ,
SMS wrote:

Ryan Cousineau wrote:
Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.

Thanks,

Thanks for the advice of everyone in this thread. I'm just responding to
Steven because I think it's worth discussing.

I'd be very very careful about this. A Cree XR-E 3W generates a lot of
heat at the junction, and housings for them are very different than for
MR11 bulbs with filaments where the heat is dissipated through the
reflector and lens. A Cree based enclosure will essentially be a cast
aluminum heat sink, with the LED very well thermally bonded to the
enclosure/heat sink.

There is no "white hot-filament," but there is a red hot junction.

Fair points all, and I will attempt to heat-sink the system. However,
I'm content to lose a $6 LED and a $6 buck/booster (actually, I'll
probably dump that into the battery pack) to science.

As for the other notes, the existence of a bunch of really nice,
well-sealed, quick-release housings in my pile of parts trumps almost
all other first efforts at enclosing these lights. I may change my mind
later, but housings are hard, soldering is not.

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

Ryan Cousineau wrote:

As for the other notes, the existence of a bunch of really nice,
well-sealed, quick-release housings in my pile of parts trumps almost
all other first efforts at enclosing these lights. I may change my mind
later, but housings are hard, soldering is not.

There were a large number of nice Cree LED XR-E lights, at ridiculously
high prices, at Interbike. One vendor was offering a show special with a
strict limit of one per person, not for resale, at a price I though was
higher than the retail price should be. All had one thing in common, and
that was that the housing was cast solid aluminum with a lot of fins for
better heat dissipation. I think one vendor offered a heat exchanger
that allowed you to use the waste heat to warm yourself on winter rides.

Chalo wrote:
jim beam wrote:
Ryan Cousineau wrote:
Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.
are you going to ensure you have a "low beam" function on that thing
like a car headlight? �because i swear, the next asshole that shines one
of your freakin' lights in my eyes next time i'm riding home in the dark
and half blinds me, i'm going to turn around, chase that asshole down,
and we're going to have a very terse little conversation.

cars have low beam for a reason. �ultra-bright bike lights need one too.

Low beam mode is trivial with LED lights, because they can be driven a
small fraction of their full intensity without appreciable change in
color. That said, there's nothing you can do with 3 or 4 watts
driving even the most efficient LED that will make its brightness
compare to that of a single 55W car headlight. They throw a larger
portion of their light above surface level because otherwise they
wouldn't put enough light there to see by.

Chalo

just like with a car light, i'm not talking about reduced output, i'm
talking about a beam dispersion that does not shine up into the eyes of
oncoming traffic.

modern bike lights have such high outputs, it's becoming a real problem.

Ben C wrote:
On 2008-09-25, jim beam wrote:
Ryan Cousineau wrote:
Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.

Thanks,

are you going to ensure you have a "low beam" function on that thing
like a car headlight? because i swear, the next asshole that shines one
of your freakin' lights in my eyes next time i'm riding home in the dark
and half blinds me, i'm going to turn around, chase that asshole down,
and we're going to have a very terse little conversation.

cars have low beam for a reason. ultra-bright bike lights need one too.

I'm not sure they need a high beam. Have the ultra-bright lights, but
you want them pointing down a bit anyway-- you're not going as fast as a
car and are more interested in the potholes.

youda thunk. but apparently some individuals are more intent on
illuminating uranus, and in the process inconsiderately dazzling other
riders, than considering more normal terrestrial hazards.

jim beam writes:

just like with a car light, i'm not talking about reduced output, i'm
talking about a beam dispersion that does not shine up into the eyes
of oncoming traffic.

modern bike lights have such high outputs, it's becoming a real problem.

I am incredibly impressed that in your area there are so many
nighttime bike riders with super-bright lights that it is
becoming a real problem. Where do you live?
--
Ben Pfaff
http://benpfaff.org

Ben Pfaff wrote:

jim beam writes:

just like with a car light, i'm not talking about reduced output, i'm
talking about a beam dispersion that does not shine up into the eyes
of oncoming traffic.

modern bike lights have such high outputs, it's becoming a real problem..

I am incredibly impressed that in your area there are so many
nighttime bike riders with super-bright lights that it is
becoming a real problem. *Where do you live?

j.b. lives in San FranRichCo. He might be seeing $500 HID bike lights
(with beam patterns designed for off-road) and assuming they're
LEDs.

Chalo

Chalo wrote:
Ben Pfaff wrote:
jim beam writes:
just like with a car light, i'm not talking about reduced output, i'm
talking about a beam dispersion that does not shine up into the eyes
of oncoming traffic.
modern bike lights have such high outputs, it's becoming a real problem.
I am incredibly impressed that in your area there are so many
nighttime bike riders with super-bright lights that it is
becoming a real problem. �Where do you live?

j.b. lives in San FranRichCo. He might be seeing $500 HID bike lights
(with beam patterns designed for off-road) and assuming they're
LEDs.

Chalo


no, it's led. hid was too expensive for a lot of people. nowadays,
practically everyone can afford led.

Chalo wrote:
Ben Pfaff wrote:
jim beam writes:
just like with a car light, i'm not talking about reduced output, i'm
talking about a beam dispersion that does not shine up into the eyes
of oncoming traffic.
modern bike lights have such high outputs, it's becoming a real problem.
I am incredibly impressed that in your area there are so many
nighttime bike riders with super-bright lights that it is
becoming a real problem. Where do you live?

j.b. lives in San FranRichCo. He might be seeing $500 HID bike lights
(with beam patterns designed for off-road) and assuming they're
LEDs.

Chalo

While I have no interest in HID lights, it should be pointed out they
have come way down in price. you can get a single HID light for around
$130, plus the cost of a 12V rechargeable battery (as little as $10).