A powerful headlamp for night skating

[John Doe]

I am in the process of modifying a Coleman LED spotlight (530
lumens) into an ultra-powerful headlamp. I am stuck on modifying
the reflector, but will get there sooner or later. The battery
will be hooked onto a belt or carried in a fanny pack, with a wire
plugged into the helmet lights. The light fixture itself is
extremely light. Unfortunately, the LED light is still not like
normal artificial light, so it might take some getting used to.

Being able to use a compact fluorescent light as an ultra-powerful
headlamp would be excellent IMO, the CFLs I use at home look
great. Maybe someday.

[inlina]

Post by John Doe
I am in the process of modifying a Coleman LED spotlight (530
lumens) into an ultra-powerful headlamp. I am stuck on modifying
the reflector, but will get there sooner or later. The battery
will be hooked onto a belt or carried in a fanny pack, with a wire
plugged into the helmet lights. The light fixture itself is
extremely light. Unfortunately, the LED light is still not like
normal artificial light, so it might take some getting used to.

What or how are you wanting to modify on the reflector?

Post by John Doe
Being able to use a compact fluorescent light as an ultra-powerful
headlamp would be excellent IMO, the CFLs I use at home look
great. Maybe someday.

LEDs are fast become more efficient than fluros and their compact form
tends to make them far better for portable lighting. Try some of the
high-end automotive LEDs from Osram (like Gloden or Platinum Dragons)
or Philips LumiLED. Optics is the big challenge with LEDs since the
effective cone is fairly defined and re-distributing the light into an
ideal pattern results in loss of efficiency. But a CFL would have a
similar problem given it has no focal point from a filament to work
with.

Xenon arc is the other option for efficient, high output lighting, but
then you have to carry around a heavy ballast and be under contant
threat of getting a high voltage shock.

CG

[John Doe]

Post by inlina

Post by John Doe
I am in the process of modifying a Coleman LED spotlight (530
lumens) into an ultra-powerful headlamp. I am stuck on
modifying the reflector, but will get there sooner or later.
The battery will be hooked onto a belt or carried in a fanny
pack, with a wire plugged into the helmet lights. The light
fixture itself is extremely light. Unfortunately, the LED light
is still not like normal artificial light, so it might take
some getting used to.

What or how are you wanting to modify on the reflector?

The stock reflectors are too focused (very tight spotlight) and
the light beam needs to be widened or defused somehow. I posted in
(sci.electronics.basics) about that. I understand the answers and
plan to try more modifications today.

Post by inlina
LEDs are fast become more efficient than fluros and their
compact form tends to make them far better for portable
lighting. Try some of the high-end automotive LEDs from Osram
(like Gloden or Platinum Dragons) or Philips LumiLED.

I am not an expert on modern LEDs, but... The Coleman LED
spotlight includes three Cree XLamp XR-E 175 Lumens LEDs for about
$55 US at a regional sporting goods store. I would be surprised if
those LEDs could be found in component form for the same money
(minus the rest of the package including the LEDs being mounted on
a circuit board with a heatsink, a battery with charging
circuitry, a switch, and plugs/jacks/wire).

Post by inlina
Optics is the big challenge with LEDs since the effective cone
is fairly defined and re-distributing the light into an ideal
pattern results in loss of efficiency.

The Cree XLamp XR-E throws light in every direction except
backwards. From many years ago, I vaguely recall that clear
undiffused white LEDs threw light forwards, but there is no
spotlight with these (without a reflector).

Anyway... I just need to get it done.

Post by inlina
But a CFL would have a similar problem given it has no focal
point from a filament to work with.

That is too bad IMO since the CFL light looks so good.

[inlina]

Post by John Doe
The stock reflectors are too focused (very tight spotlight) and
the light beam needs to be widened or defused somehow. I posted in
(sci.electronics.basics) about that. I understand the answers and
plan to try more modifications today.

Try it witout the reflector also and see if you get a pattern you
like. Typical LED cone angles are around the 30degree mark. Although
the Cree ones may be wider (didn't read the spec sheet).

Post by John Doe
I am not an expert on modern LEDs, but... The Coleman LED
spotlight includes three Cree XLamp XR-E 175 Lumens LEDs for about
$55 US at a regional sporting goods store. I would be surprised if
those LEDs could be found in component form for the same money
(minus the rest of the package including the LEDs being mounted on
a circuit board with a heatsink, a battery with charging
circuitry, a switch, and plugs/jacks/wire).

Yeah, that's reasonably cheap, but you could use that as a base and
slot in another LED. Depends on the form of them though as you might
need a secondary board. You shouldn't need the heatsinks if you use
some of the off the shelf pre-mounted Dragons.

Post by John Doe
The Cree XLamp XR-E throws light in every direction except
backwards. From many years ago, I vaguely recall that clear
undiffused white LEDs threw light forwards, but there is no
spotlight with these (without a reflector).

Yeah, typical cone angle is 30degrees for the main part of the beam
and they fall away from there. You can buy optics online that just sit
over the top of the LED's dome optic (if it is domed) and generate
alternate patterns like squares and ovals.

These guys have them to suit Cree XR-Es and you can buy samples. You
can then play with defocussing them slightly to tweak the pattern you
want....

http://www.led-spot.com/p_cree.shtml

CG

[John Doe]

Post by inlina

Post by John Doe
The Cree XLamp XR-E throws light in every direction except
backwards. From many years ago, I vaguely recall that clear
undiffused white LEDs threw light forwards, but there is no
spotlight with these (without a reflector).

Yeah, typical cone angle is 30degrees for the main part of the
beam and they fall away from there. You can buy optics online
that just sit over the top of the LED's dome optic (if it is
domed) and generate alternate patterns like squares and ovals.
These guys have them to suit Cree XR-Es and you can buy samples.
You can then play with defocussing them slightly to tweak the
pattern you want....
http://www.led-spot.com/p_cree.shtml

I bought two of the 14° spot and two of the 12° x 48° oval, plan
to use two of one and one of the other. The LED lenses have an
adhesive underneath that apparently goes over the individual LED
circuit board and sticks on top of the module circuit board. They
are bigger than I thought, the screws that hold the LED module to
the heatsink will need modification to make room for them. The
aluminum heatsink weighs about 3 ounces, the whole helmet part
will weigh little more than that. The current regulator circuit
that came with the spotlight (could be a buck regulator, I guess)
is being used, after removing the sealed lead acid battery
charging and momentary switch stuff. Planning to use eight AA NiMN
(Eneloop) batteries. Those eight batteries weigh 1/2 pound, one
third of what the next option for powering the headlamp weighs.
None of my lithium ion batteries fit the application. The OFF
current is about 3 microamps. The ON current is about 800
milliamps. Not sure how long the eight AA batteries will run the
thing, will find out after the 3 LED module is correctly
heatsinked. The thing should rock if/when the lenses are correctly
mounted. A headlamp makes a big difference when skating at night
in the city.