:bigsmile: Just don’t turn it on within 20 miles of an airport. The helicopter that comes for you will have Bruce Willis as well as Chuck Norris in it.
I got in the Big Honkin’ Reflectors (ok, 90mm is not that big) from Illumination Machines. Whacked 5mm of the bottom of one to get a 34mm hole. It cranks out 70,000 lux at 1 meter (around 10 degree beam width). The beam is as smooth as a baby’s behind. I’ll try and get some pics up soon.
Old-Lumens 1.3 mile SST-90 Aspheric Potato Masher Thrower does 39,000 lux at 1 meter. A Jacob A60 does around 35,000 lux at 1 meter. These lights have a considerably tighter beam.
Holy mother. This is very badass.
What kind of portable power source is used to power a light of this magnitude?
It can run on 12V to 30V DC. At 12V it pulls around 15 amps. I was going to (and still might) power it with a 4S A123 20Ah LiFePO4 pack, but A123 is in a bit of a financial meltdown at the moment and their cells may no be viable in the long term. Or any 4S-6S LiPo pack. Or a car.
Here’s a pic of the reflector sitting on the LED:
Here it is lighting up the sphere ’o many mysteries. What is not obvious is that the room is also lit by 10,000 lumens of overhead lighting. For some reason, those lumens take a back seat to the big guy:
Beam shot with reflector. Ceiling is 8 feet from the top of the reflector. Those PAR20 fixtures are 3 feet apart in the Y axis and 4 feet in the X axis.
Are you sure your sphere's not about to catch fire? It also appears that you have an interesting collection of electrical wiring and gadgetry there. Looks like fun.
Doing a little trig on the beamshot image looks like the beam width (full width) out of the reflector is around 16 degrees (with an SST-90 it is supposed to be 10 degrees). Works out to around a .25 lux spot around 600 feet wide at 2000 feet.
Funny you should ask… the lights sit on a couple of blocks of polyethylene foam to get them up to the sphere port. I started a run (with a different heatsink) and after around 5 minutes of observation went to work on the computer in the other room. Sometime later I heard a loud BANG!
What happened was one of the cheap Chinese clip leads to the fan decided to uncrimp the connection between the wire and the clip (hint, only buy leads that are soldered). LED lost cooling, temp rose to over 100C. The heatsink and LED then did their best imitation of the China Syndrome and melted their way through the foam blocks (perfect, form fitting rectangular hole). About 3/4 the way through the foam, one of the power connections to the LED unsoldered itself. The LED driver wanted to keep 5A to the LED, but saw no current flowing so it kept increasing the output voltage. A couple milliseconds later, the voltage exceeded the 35V output capacitor rating and the cap blew with a satisfying BANG (I’ve since added a diode that keeps the output voltage below 35V.
I did a couple more lux tests. With no reflector (120+ degree beam) it did 7000 lux at 1 meter.
With the 90mm aspheric it did 50,000 lux. I can’t get the lens close enough to the emitter to project a tight image since it is mounted in the SST-90 maglight head. The beam was around the same size as with the reflector, but with less spill.
some night time beam shots me interested :party:
The problem with night time beam shots is when I turn it on, the night time seems to disappear 8)
All of these crazy builds you have and I have yet to see an outdoor beam shot ;)
There is one of a 5000 lumen array here: How To Build a Flashlight With Perfect Modes (picture heavy)
There is?? I just see daylight there :p
Yep, that’s the problem. Nighttime hides when the big boys come out to play.
The 15,000 lumen device is wired to a bunch of instruments… not very portable.
I got in a couple of those 600 watt drivers (http://www.ebay.com/itm/DC-DC-600W-10-60V-to-12-80V-Boost-Converter-Step-up-Module-Power-Supply-/170893208817?pt=LH_DefaultDomain_0&hash=item27ca076cf1) They are about 3 times the volume of the 150 watt one. They don’t require any mods for constant current output. They come shipped from the factory set for 56V out and 2.5A (ymmv). It also has a fuse on the input so that if the output FET shorts your batteries won’t get all uppity and kill you.
I cranked the output voltage setting down to 33V (a little above the led array Vf) and fired it up. Voila lotsa light. Cranked the current up to 5A. Voila, mega freakin’ lotsa light. Efficiency is around 90%. The heatsink barely gets warm so it doesn’t need much in the way of airflow to keep it happy.
Next I tried it with the dimmer. It works a lot better, but below around 35% I get an occasional blip (maybe every couple of seconds) but no puke mode flicker. It is worse at 35 kHz PWM than at 120 Hz. I need to play some with different PWM rates and see how it behaves.
I may just not use PWM for dimming, but instead wire an external pot in place of the driver’s 100K current limit pot. I checked and 9.09K gives me 5A, 56K gives 2.5 A. I figure a 9K resistor in series with a 100K pot should be just about right.
By not having to PWM the LED, that frees up a pin on the micro and I can do all the monitoring and thermal/battery protection with a ATTINY85 (or TINY13 for that matter). Using a micro that has more pins/ADC channels would let me independently monitor each cell in the battery pack, though.
Before adding an external current limit pot to the driver, I figured it would be a good idea to try running the one on the board through it’s range. It won’t go below 1.25A.
Around the 2.5A area it gets a bit woogedy. Just touching the pot with a screwdriver or even touching the (isolated) heat sink causes the current to shift around 200 mA. Above or below 2.5A and it is OK.
Dim it, damn it! Who’d a thought dimming a 150 watt LED would be such a pain… I really don’t want to have to design my own boost driver just to get a decent dim.
I took the 100K current limit pot off the board of one of the drivers and replaced it with an external 500K pot. That lets it dim down to 600 mA (about 10%). For the best dimming profile the pot should be an audio taper pot.
There is the same glitch in the current output around 2.5 amps. As you increase the current from 2.5A to 3A, the current drops back down to 2.5A and then starts rising again as you turn the pot some more. This issue looks like it is inherent to the driver design.
There are a couple of issues with using the a manual current adjust pot to do the dimming instead of PWM. First is a potential color temperature shift with LED current. This does not seem to be a problem with the Bridgelux arrays.
Second is the fact that the control processor can’t do things like backing off the LED drive if the battery voltage starts falling or the LED starts overheating… you can only turn the light off. There are some digitally controlled pots out there that might be usable.
We are all still following this even though were not responding. Keep it up.