Well a little project started in my head, and I needed a little info. I have a nice 5 watter, and it seems 2 350ma micropucks powered by 2 AA light up just fine. Now I wanted to know if it produces so much heat I will need a large heatsink? I am not too sure about anything yet, and I cant really test out much because the wires and batteries keep falling apart and I cant keep it together. Will I need a lot of heatsinking?
Lux V driven at 700 ma out of 3V=how much heat?
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Endeavour
Flashlight Enthusiast
I don't know how friendly 2AAs are with Luxeon Vs, but the LED is rated at 6 volts, not three. Single CR123s are NOT very happy when you demand 700 milliamps to such a load as the Luxeon V - I've had an Arc LS mod accidentally turn itself on after being built, here's what happened:
The battery shifted when the light was set on a bookshelf, it turned on while I was on my way out back outside to take care of some stuff in the shop. I was there for about five minutes.
During this time, the light puttered along, cooking itself.
I came back, sat down at the desk, and started working on another board, and ask my friend, who was the one who set the light down, to hand it to me and let me take a look at it. Rather nervously he handed it to me, warm, and told me he had burned himself when he turned it off, that it had turned back on when we left.
Well. The first thing that was noticed was the UCL was lightly fogged and the reflector, an IMS 17mm, which is normally smooth, was now sputtered. The light was pressurized from the inside, air escaped when it was opened. The battery was taken out - it had ejected white goo, and was making audible noises. It was thrown outside in the thicker trash can, just to be safe. When the light was unscrewed, the reflector was taken off, and it was half-melted to the LED, lens, and heatsink. The lens was pretty well stuck to the O-Ring sealing the head. The dome of the LED peeled off of the phosphor layer of the LED, leaving a bubble in between the two parts.
In order for an LED to get damaged, it has to get hotter than 190 degrees farenheit. I can say with relative certainty that it was far hotter than that, given the extent of the damage.
This story isn't so much to dissuade you, but more to serve as a warning. A number of people have requested single celled builds for Luxeon Vs, and if they understand the risk and accept it, and are responsible enough to properly use the light so that nothing similar or worse than what happened to that one build happened to them, I've no problem building it for them. The point is simple: be careful when under driving LEDs at high currents.
To more directly answer your actual question, the Luxeon LED produces a fair amount of heat at 700mA. You'll need a fair amount of heatsinking if you want to run it for any reasonable amount of time, a 1.5" diameter aluminum rod some 3 inches tall, maybe with fins on it, should provide enough mass for you to be able to experiment with the LED for a good amount of time without it getting too hot to handle. Of course, the more area you have to dissipate the heat, the better.
Good luck.
The battery shifted when the light was set on a bookshelf, it turned on while I was on my way out back outside to take care of some stuff in the shop. I was there for about five minutes.
During this time, the light puttered along, cooking itself.
I came back, sat down at the desk, and started working on another board, and ask my friend, who was the one who set the light down, to hand it to me and let me take a look at it. Rather nervously he handed it to me, warm, and told me he had burned himself when he turned it off, that it had turned back on when we left.
Well. The first thing that was noticed was the UCL was lightly fogged and the reflector, an IMS 17mm, which is normally smooth, was now sputtered. The light was pressurized from the inside, air escaped when it was opened. The battery was taken out - it had ejected white goo, and was making audible noises. It was thrown outside in the thicker trash can, just to be safe. When the light was unscrewed, the reflector was taken off, and it was half-melted to the LED, lens, and heatsink. The lens was pretty well stuck to the O-Ring sealing the head. The dome of the LED peeled off of the phosphor layer of the LED, leaving a bubble in between the two parts.
In order for an LED to get damaged, it has to get hotter than 190 degrees farenheit. I can say with relative certainty that it was far hotter than that, given the extent of the damage.
This story isn't so much to dissuade you, but more to serve as a warning. A number of people have requested single celled builds for Luxeon Vs, and if they understand the risk and accept it, and are responsible enough to properly use the light so that nothing similar or worse than what happened to that one build happened to them, I've no problem building it for them. The point is simple: be careful when under driving LEDs at high currents.
To more directly answer your actual question, the Luxeon LED produces a fair amount of heat at 700mA. You'll need a fair amount of heatsinking if you want to run it for any reasonable amount of time, a 1.5" diameter aluminum rod some 3 inches tall, maybe with fins on it, should provide enough mass for you to be able to experiment with the LED for a good amount of time without it getting too hot to handle. Of course, the more area you have to dissipate the heat, the better.
Good luck.
Re: Lux V driven at 700 ma out of 3V=how much heat
Well I have the inside of a D cell mag head to serve as heatsinking plus a stack of coins. Ill try to get them as long and thick to your specifications. I need the inside of the head for heatsinking and the 2 micropucks plus the wires to go around inside. Not too sure if I have the room though. Still have to experiment a bit.
Well I have the inside of a D cell mag head to serve as heatsinking plus a stack of coins. Ill try to get them as long and thick to your specifications. I need the inside of the head for heatsinking and the 2 micropucks plus the wires to go around inside. Not too sure if I have the room though. Still have to experiment a bit.
Mags,
This is an interesting concept. Very interesting. According to the micropuck's spec sheet, it's rated at 3v in and an absolute max of 8v out. I don't know for sure what this means for your application. I'm going to go wire one up and feed it with my bench power supply. I'll see if it self destructs.
This is an interesting concept. Very interesting. According to the micropuck's spec sheet, it's rated at 3v in and an absolute max of 8v out. I don't know for sure what this means for your application. I'm going to go wire one up and feed it with my bench power supply. I'll see if it self destructs.
Re: Lux V driven at 700 ma out of 3V=how much heat
I was going to buy one of those D cell mag head to AA body adapters, then use the inside of the head for the wires of the micropuck and stuff. I thought the head and a coin stack would be enough but I havent been able to check how much space exactly I have. Mr Bulks Space needles threw incredibly well in a mag c reflector which is the same as the D head reflectors. Mr Bulk got around 8,000 lux off of a luxeon V direct driven by 3 123s, so if I stepped up current a bit, I thought I would get about half at least? Even half of that is a lot. Or maybe I went crazy as usual... Mr Tony, be careful when you do it. Endeavours post kinda worries me...
I was going to buy one of those D cell mag head to AA body adapters, then use the inside of the head for the wires of the micropuck and stuff. I thought the head and a coin stack would be enough but I havent been able to check how much space exactly I have. Mr Bulks Space needles threw incredibly well in a mag c reflector which is the same as the D head reflectors. Mr Bulk got around 8,000 lux off of a luxeon V direct driven by 3 123s, so if I stepped up current a bit, I thought I would get about half at least? Even half of that is a lot. Or maybe I went crazy as usual... Mr Tony, be careful when you do it. Endeavours post kinda worries me...
OK, here's what I did. I wired up a micropuck to a VYOT Lux V. I used a bench power supply dialed in to 3v. The current draw from the power supply was 390mA. The current getting to the Luxeon was 170mA.
The heat generated by the luxeon was non existent. I couldn't feel anything. I'm going to assume that running two micropucks would get you double what I have quoted up top. So...even if you run two micropucks in parallel, you'll only get around 300mA to the Lux V.
You just have to understand that boosting from 3v up to the Vf of a Lux V is a huge step and likely can't be accomplished. Not with the power source that you are talking about anyway.
With that being said, I do have to say that a Lux V running at 170mA puts out a healthy amount of light. While it was running, I turned out all of the lights in my shop, and after my eyes adjusted, I thought, "geez, that's a lot of light."
Just out of curiosity, I dropped an IMS reflector on top of the star and it made a nice pattern on the ceiling.
Mags, I want to thank you for my next idea for a mod. This could very well replace my Arc AAA as being my "always have it with me" light. Since I always wear a suit, this could just go in my pocket with the rest of my pens.
As a point of interest, I dialed the power supply down to 1.2v to see what would happen. Current draw dropped to about 230mA and the current to the LED dropped to about 40mA. Still a very useable amount of light.
Also noticed that, while running at 3v, the micropuck had gotten very slightly warm to the touch. Very slightly.
I'm going to let it run all night and see what happens.
I think that this is a very worthwhile mod.
Good luck.
Oh, BTW, what I also find interesting is that a Lux III WILL generate heat while being run from a micropuck, but the Lux V doesn't.
I'm wondering if driving a Lux III or 1W to spec with a micropuck would yield the same amount of overall light as driving the Lux V with the micropuck. If it does, then going with the under driven Lux V may be the ticket. In terms of heat anyway.
The heat generated by the luxeon was non existent. I couldn't feel anything. I'm going to assume that running two micropucks would get you double what I have quoted up top. So...even if you run two micropucks in parallel, you'll only get around 300mA to the Lux V.
You just have to understand that boosting from 3v up to the Vf of a Lux V is a huge step and likely can't be accomplished. Not with the power source that you are talking about anyway.
With that being said, I do have to say that a Lux V running at 170mA puts out a healthy amount of light. While it was running, I turned out all of the lights in my shop, and after my eyes adjusted, I thought, "geez, that's a lot of light."
Just out of curiosity, I dropped an IMS reflector on top of the star and it made a nice pattern on the ceiling.
Mags, I want to thank you for my next idea for a mod. This could very well replace my Arc AAA as being my "always have it with me" light. Since I always wear a suit, this could just go in my pocket with the rest of my pens.
As a point of interest, I dialed the power supply down to 1.2v to see what would happen. Current draw dropped to about 230mA and the current to the LED dropped to about 40mA. Still a very useable amount of light.
Also noticed that, while running at 3v, the micropuck had gotten very slightly warm to the touch. Very slightly.
I'm going to let it run all night and see what happens.
I think that this is a very worthwhile mod.
Good luck.
Oh, BTW, what I also find interesting is that a Lux III WILL generate heat while being run from a micropuck, but the Lux V doesn't.
I'm wondering if driving a Lux III or 1W to spec with a micropuck would yield the same amount of overall light as driving the Lux V with the micropuck. If it does, then going with the under driven Lux V may be the ticket. In terms of heat anyway.
Re: Lux V driven at 700 ma out of 3V=how much heat
Your very welcome Mr T. Glad I helped you in a way. So its a green light for what Im about to do I guess? 2 micropucks, 1 coin stack heatsink up to the specifics of endeavour, large D cell mag head, 's all good?
Your very welcome Mr T. Glad I helped you in a way. So its a green light for what Im about to do I guess? 2 micropucks, 1 coin stack heatsink up to the specifics of endeavour, large D cell mag head, 's all good?
Another thing. I took a voltage reading off of the lux while it was running and got a reading of 5.9v, so the micropuck is doing a hellava job of boosting.
Now I just have to draw up a light that would fit this configuration. I'm thinking that I'll go with a single 123 configuration, so that I can put it on a keychain rather than in my pen pocket.
Now I just have to draw up a light that would fit this configuration. I'm thinking that I'll go with a single 123 configuration, so that I can put it on a keychain rather than in my pen pocket.
Endeavour
Flashlight Enthusiast
I didn't know you were wrapping up the package into a modified Maglite, I thought you were just building up a module to experiment with. I'll let someone else chime in here with better ideas on how to heatsink it into your light.
As for three CR123s driving a Luxeon V: That's overdriving the LED, exactly by how much, I don't know. Voltage = Current * Resistance; I don't know the resistance of your typical Luxeon V LED, but most are rated at about 6V, 700mA, so, assuming those values, you have a resistance of about 8.6 ohms on the LED.
Using 3 123s gives you about 9 volts on fresh cells, so, dividing 9 by 8.6 gives you 1.047, or about 1047mA. The harder you drive an LED, the less life you get out of it, and the more it shifts towards a bluer color. If I recall, the Luxeon V has 70% lumen maintenace (so it stays close to what it was binned at) for 500 hours, if driven at 700mA. The LED will run longer than 500 hours, but you do, over time, get progressively more diminishing output, and the higher you drive it, the faster it comes about. Thermal design (poor), and other nuances also decrease the usable lifespan of the LED. Also, please note that fins are a VERY bad idea if you're putting the module inside another tube - you need the thermal junction to be flush against it to properly transfer the heat from your heatsink slug to the outer tube, and into the air. Fins are only good when the part is exposed to air, since it increases the surface area that it can be cooled over.
Just because Mr Bulk and others over drive the LEDs to create rockets doesn't mean it's necessarily the best thing to do in every application. Peter Gransee had a 3x overdrive (60mA vs. rated 20mA) on the Arc AA and AAA, and the ones I've handled have been an angry blue. People would buy new ones a few months after using their older ones for a while, and wonder what had been changed that the new LEDs were brighter than the old ones. Phosphor degradation is real, and you will be able to notice it within the 500 hours of the Luxeon V's rated life when comparing it to new LEDs. The question you have to ask yourself is whether or not you want a long lived device that you don't have to be replacing the LED on as though it were an incandescent bulb, or if you want a shorter-lived LED rocket. If you're looking for maximum output of light, folks are really digging in the wrong place with LEDs right now for that. You already seemed to answer that question, though. /ubbthreads/images/graemlins/wink.gif
As for three CR123s driving a Luxeon V: That's overdriving the LED, exactly by how much, I don't know. Voltage = Current * Resistance; I don't know the resistance of your typical Luxeon V LED, but most are rated at about 6V, 700mA, so, assuming those values, you have a resistance of about 8.6 ohms on the LED.
Using 3 123s gives you about 9 volts on fresh cells, so, dividing 9 by 8.6 gives you 1.047, or about 1047mA. The harder you drive an LED, the less life you get out of it, and the more it shifts towards a bluer color. If I recall, the Luxeon V has 70% lumen maintenace (so it stays close to what it was binned at) for 500 hours, if driven at 700mA. The LED will run longer than 500 hours, but you do, over time, get progressively more diminishing output, and the higher you drive it, the faster it comes about. Thermal design (poor), and other nuances also decrease the usable lifespan of the LED. Also, please note that fins are a VERY bad idea if you're putting the module inside another tube - you need the thermal junction to be flush against it to properly transfer the heat from your heatsink slug to the outer tube, and into the air. Fins are only good when the part is exposed to air, since it increases the surface area that it can be cooled over.
Just because Mr Bulk and others over drive the LEDs to create rockets doesn't mean it's necessarily the best thing to do in every application. Peter Gransee had a 3x overdrive (60mA vs. rated 20mA) on the Arc AA and AAA, and the ones I've handled have been an angry blue. People would buy new ones a few months after using their older ones for a while, and wonder what had been changed that the new LEDs were brighter than the old ones. Phosphor degradation is real, and you will be able to notice it within the 500 hours of the Luxeon V's rated life when comparing it to new LEDs. The question you have to ask yourself is whether or not you want a long lived device that you don't have to be replacing the LED on as though it were an incandescent bulb, or if you want a shorter-lived LED rocket. If you're looking for maximum output of light, folks are really digging in the wrong place with LEDs right now for that. You already seemed to answer that question, though. /ubbthreads/images/graemlins/wink.gif
What are your going to put this into? Driving the 5W with two micropucks is only going to get you about 300mA to the LED. I would go putting this into a big ole mag light. This would be nice for a small pocket light, but this all of the heft of a mag light, I'd drive the luxeon a bit harder.
I have to agree with the above. Direct drive is not the best way to do things, unless all out performance (as short lived as it may be) is what you're after.
5W luxeons have a relatively short life span as it is. Driving one to over 1A is going going to cut it shorter.
If you are, indeed, going to be putting this into a Mag light, you might want to look to a different driver. If you must go DD with 123s, you should use a DMM to find the actual Vf of your luxeon and tailor the reistance accordingly.
If you are just dead set on using the micropucks, perhaps you should consider doing the mod with a Lux III or 1W. If you don't have any, I might be able to dig something up.
I have to agree with the above. Direct drive is not the best way to do things, unless all out performance (as short lived as it may be) is what you're after.
5W luxeons have a relatively short life span as it is. Driving one to over 1A is going going to cut it shorter.
If you are, indeed, going to be putting this into a Mag light, you might want to look to a different driver. If you must go DD with 123s, you should use a DMM to find the actual Vf of your luxeon and tailor the reistance accordingly.
If you are just dead set on using the micropucks, perhaps you should consider doing the mod with a Lux III or 1W. If you don't have any, I might be able to dig something up.
Endeavour
Flashlight Enthusiast
Re: Lux V driven at 700 ma out of 3V=how much heat
Nothing driven at anything below recommended specifications really merits being called a discovery... Under driving an LED is nothing new. Most folks don't do it with the Luxeon V because it's cost prohibitive. Why spend $20-40 on an LED when a $6-15 Luxeon I or III will do the same job?
Most people here are only answering your questions and commenting on your build of choice, not flabbergasted by the underdrive of an LED.
Nothing driven at anything below recommended specifications really merits being called a discovery... Under driving an LED is nothing new. Most folks don't do it with the Luxeon V because it's cost prohibitive. Why spend $20-40 on an LED when a $6-15 Luxeon I or III will do the same job?
Most people here are only answering your questions and commenting on your build of choice, not flabbergasted by the underdrive of an LED.
chrisse242
Enlightened
Re: Lux V driven at 700 ma out of 3V=how much heat
[ QUOTE ]
Chop said:
Another thing. I took a voltage reading off of the lux while it was running and got a reading of 5.9v, so the micropuck is doing a hellava job of boosting.
Now I just have to draw up a light that would fit this configuration. I'm thinking that I'll go with a single 123 configuration, so that I can put it on a keychain rather than in my pen pocket.
[/ QUOTE ]
I know you can do it yourself in a heartbeat, but why draw up a light if you only have to buy a jil 1.3 and replace the luxIII with a luxV? There already is a micropuck in there and it will be even smaller with the cr2.
Chrisse
[ QUOTE ]
Chop said:
Another thing. I took a voltage reading off of the lux while it was running and got a reading of 5.9v, so the micropuck is doing a hellava job of boosting.
Now I just have to draw up a light that would fit this configuration. I'm thinking that I'll go with a single 123 configuration, so that I can put it on a keychain rather than in my pen pocket.
[/ QUOTE ]
I know you can do it yourself in a heartbeat, but why draw up a light if you only have to buy a jil 1.3 and replace the luxIII with a luxV? There already is a micropuck in there and it will be even smaller with the cr2.
Chrisse
Re: Lux V driven at 700 ma out of 3V=how much heat
Mags,
It is somewhat of a discovery for me. I would never have even thought of driving a 5W with a micropuck.
The point that Endeavor makes is true. The Lux V is much more expensive than a Lux I or III, but I wouldn't go so far as to say that each will do the same job.
The big deal for me was the heat, or lack thereof. I know that a Lux I being driven by a micropuck will get hot. You can take an older KL1 which drives the luxeon at about 350mA. During extended use, it will get hot. Not too hot for me, but too hot for some. I can remember going crabbing with my 6 year old and having to take two lights for him. When one got too hot for him to hold, I'd have to give him the other one.
I don't have an integrating sphere, so I can't confirm this; but, assuming that the Lux I and Lux V put out equal amounts of total light while being driven by a micropuck, I'd rather use the Lux V, just because of the lack of heat. The beam pattern is also nice for a very small light.
When I truly need my lights, I tend to run them for a long time and the lack of heat is just more important to me than it is to most.
Underdriving luxeons is not new though. Many have been doing it for a long time. Luxeons are more efficient at lower current levels and become more inefficient as you increase the current. You'll get more light out of three Lux IIIs running at 500mA each than you will from a single Lux III running at 1500mA.
Mags,
It is somewhat of a discovery for me. I would never have even thought of driving a 5W with a micropuck.
The point that Endeavor makes is true. The Lux V is much more expensive than a Lux I or III, but I wouldn't go so far as to say that each will do the same job.
The big deal for me was the heat, or lack thereof. I know that a Lux I being driven by a micropuck will get hot. You can take an older KL1 which drives the luxeon at about 350mA. During extended use, it will get hot. Not too hot for me, but too hot for some. I can remember going crabbing with my 6 year old and having to take two lights for him. When one got too hot for him to hold, I'd have to give him the other one.
I don't have an integrating sphere, so I can't confirm this; but, assuming that the Lux I and Lux V put out equal amounts of total light while being driven by a micropuck, I'd rather use the Lux V, just because of the lack of heat. The beam pattern is also nice for a very small light.
When I truly need my lights, I tend to run them for a long time and the lack of heat is just more important to me than it is to most.
Underdriving luxeons is not new though. Many have been doing it for a long time. Luxeons are more efficient at lower current levels and become more inefficient as you increase the current. You'll get more light out of three Lux IIIs running at 500mA each than you will from a single Lux III running at 1500mA.
