Hi every one, and welcome to my first official build thread. I have been wanting to do this for a while, but just never got around to posting more than a few pictures for a sales thread or explanation in someone else's thread. I'm not sure I would classify this as a full blown "how to" thread since duplicating the results exactly may not be ideal for all, but it is my hope that readers will learn and at the very least be inspired by this when they venture on their own.
This is actually the first time I have used a Luminus led, and I must say that I am quite pleased with the results. I have found that these leds have a nice color, and seem to be far more robust than MCE or P7 emitters. Enough about that, off we go...
For a host I chose the Ultrafire A10B that I used in my other EDC projects because they are simple to use, and have a thicker body than other small 18650 hosts I have used. I also think they are one of the best looking too.
To start I of course removed the factory R2 and driver from the pill, that simply unscrews from the head.
For my Led I chose the 4500k neutral white SST-50 from Avnetexpress.com
I don't like using bare emitters unless I have no alternative. I just don't think even the best heat sinking with thermal compounds compares to the fast acting heat dispensation you get using a star. Since the only SST/R-50s I could find were on 20MM stars too big for this type of project I had to improvise.
It just happens that thermal and electrical path of the SST-50 is identical to that of a Cree XRE, so I removed a damaged Q3 from the board and used that.
(The board I actually use was in a bit nicer condition than the one pictured, but I didn't decide to do this thread until after I had assembled it)
I didn't have any solder paste at the time, but no matter. Just put a very small amount of solder on the pad and + - connects under the led. All you really need is enough to cover it with a thin layer. Putting solder on the led is unnecessary, and it may cause the led to be raised off the board slightly. I did however put a tiny bit of flux on the led before adhearing it to the PCB.
Next simply clamp the PCB in a way that it will not loose heat quickly (ie don't just clam it in the vice) Align the led, then heat the board. For this I just used my soldering iron. Its a fairly hot iron so it wets the solder on this tiny board quicly.
As soon as the solder melts, I quickly remove the heat and touch an ice cube to the bottom of the board so that the led does not stay hot any longer than needed.
If you don't have a soldering iron that will melt the solder quickly, another way I have done these for larger thick PCBs is to clamp some wide aluminum flat bar into the vice, set the PCB on top of that, and then heat it from underneath with a propane torch.
Once this is done just glue the led to the heat sink with a thin layer of Arctic Alumina or Arctic Silver epoxy.
At first I decided to install a 3 mode MCE driver from Shiningbeam thinking that 2.5 amp would be good enough for a high. This failed to please me for several reasons I will explain. Even after letting the light run what I thought was long enough to do a "burn in" a few times the output just did not impress me.
So without much hesitation I decided to go direct drive with it. This proved to be slightly better, but still not what I expected, even on an IMR cell. I took some measurement from the tail and found that I still was not getting the current I needed to the led. Wanting to see just how hard I could drive this thing, I series connected 4 fully charged Duraloops and connected them to the light using my DMM. I figured that with that much extra voltage I could power through the extra resistance of the DMM to at least find out how far I could push the emitter.
When I touched the DMM lead to the final connection it instantly jumped to 4+ amps and then in a few seconds climbed higher, and higher to about 5.86 amps where the soft yellow light began to shift to a light blue, where I disconnected the power. Now that I knew the heat sinking was adequate for the current it was time to get there using one cell.
At the time I was using a forward click tail switch that I got from Shiningbeam. This switch was a great replacement for the factory switch when I used if for XPG applications, but for the 5A drive of an SST it proved to be flawed. Guessing that this was my weak point since I had already beefed up the top end to DD using 22g copper wire, I proceeded to mod the tail cap.
At first I just wanted to see if it would help so I removed the switch, and just threw in a chunk of solid aluminum, on one regular 18560 the light was clearly brighter and the color of the led had not yet shifted to blue. Immediately after I slipped in and IMR cell. With the light already warm from the first test the color of the led INSTANTLY became nasty blue/purple😱. I could hardly get the cap off fast enough to save my precious led. Fortunately as I mentioned before these led are far more robust than the MCE or P7. I think had I put that much current through one of them I may have been looking at having only 3 or 2 dies left if any at all.
Since I now know where the problem lies its only a matter of fixing it. After some deliberation and a few attempts at some other stuff I decided the best thing to do was to mod the cap to a twisty.
Here is what it looked like.
I removed all the parts in the center leaving only the aluminum core, and replaced the feeble spring and other stuff with a solid 3/8" aluminum rod.
Basically what you want to do is replace the amount of metal on the left with the amount of metal on the right :naughty:.
This rod fits almost perfect inside the hole in the center. Next rather than trying to mash or wedge the rod in to get a tight fit I use something I think is a little know secret to weld it in place.
Yep that's right using my propane torch and a rod of HTS-2000 you can weld aluminum. Its not quite as easy as it looks to form indestructible bonds as show in some of the sales videos, but it does work.
I don't know what kind of resistance this stuff has (probly not bad since its an aluminum alloy), but since the alum rod is touching the base of my switch core for this application its a non issue.
So now here is the new vs old.
A quick check with the IMR cells shows that we still get a very quick color shift with this new tail, probably running upward of 6+ amp since the shift at 5.8A was light and gentle, and this is quick and severe.
This brings us to the next obstacle. A standard 18650 still will not drive this to the edge of color shift where I want, and an IMR gets it there far too quickly, so time to build a driver
.
I just love the 7135 chip type drivers because they are cheap versatile, and easy to use. I ordered a 10 pack from Kaidomain. I use to wish that they would sell a smaller pack, but after having used several of them I am glad I got 10. Lets get started.
The first thing you will need to do is remove the Vdd pin from the boards and replace it with some fairly thick wire. I use 22g for this entire project.
As you can see the board on the bottom right still has the pin I am speaking of on it, and the other three have a silver wire soldered in place of it. I always remove this pin now because I have had trouble using a stack of these in parallel with it in place. However by doing this I think you loose the reverse poll protection provided by the driver.
I wont go into a huge lot of detail about assembling this stack because there is already a lot of info on available on the forum about it. I will say that basically what you need to do is connect all the pos legs, all the neg legs, and all the ground. Each chip has 3 legs and a tail. If you look at the chip with the 3 pins facing up, the pin on the left is POS the center and the tail are ground and the pin on the right is Neg.
I assembled the first two boards back to back with the pos connection running through the center attached to each board.
I then cut a groove with my dremel right behind the tail of the 2 ground pins and soldered them together. I also cut a groove for the parallel neg connection. Parallel neg can be made either by a jumper wire from the right leg of one of the pins on the top board to the right leg on the bottom board (just make sure you get the correct leg), or in this case I used the silver dot that would have been the led neg on both boards. I then added a 3rd board to make the current limit on the driver 4.2 amp.
This final board will face the battery for the pos connection.
Since I accidentally broke the little brass ring that the driver usually solders to I took this as an opportunity to beef that up as well. I used what I think was a 1/2" copper pipe coupler. I just cut a ring off, and narrowed it to the proper circumference. Then soldered it to the top of the driver.
Next I pressed it into the base of the pill, trimmed the wires, and soldered them to the led.
The extra length of the new driver eliminates the need for a spring, and also gives the battery something firm to press against, which works better for the twisty tail cap.
When I re-assemble the light I like to use deoxit gold on all the metal to metal contacts. Its good to lubricate threads, but mostly I use it because it has been proven to lower the resistance between electrical connections.
One final thing I will mention before we go to the beam shots. I have a strong dislike for battery rattle, so I added a plastic ring with a rubber base to the tail cap. It sits just above the base of the neg post. This prevents both the rattle, and more important it disables the light from coming on accidentally even for a moment.
Well guys all this threading has made me a bit tired :tired:. Think I'll just skip the beam shots and leave it at that....
:nana: 
Just kidding 😀
First up DX 2AA light
XPG R5 @ 1.4A from Solarforce L2
EDC SST-50
DX 2AA
XPG R5
EDC SST
DX 2AA
XPG R5
EDC SST
On a wall
DX 2AA XPG R5 EDC SST
I hope this thread has been fun and informative. Thanks for looking.
At this time I would also like to thank the other members who pioneered the effort with this driver, and helped me to understand its true nature. Thanks to Netkidz, ti-force, Der Wichtel TorchBoy, and all the many others who took the time to help me learn to get the most out of it.
I would like to send shout out to Techjunkie for his research and documentation on the subject of DMM resistance and color shift of the Luminus Led.
I have always been suspicious of the readings given by a DMM especially in high current situations. I wandered how could all that current pass through the tiny pin points of those leads. Any way in his youtube video he presents what I feel is compelling evidence that this is true, and also offers a simple solution to aid in getting a more accurate estimate of current flow. Thanks Techjunkie:thumbsup:
This is actually the first time I have used a Luminus led, and I must say that I am quite pleased with the results. I have found that these leds have a nice color, and seem to be far more robust than MCE or P7 emitters. Enough about that, off we go...
For a host I chose the Ultrafire A10B that I used in my other EDC projects because they are simple to use, and have a thicker body than other small 18650 hosts I have used. I also think they are one of the best looking too.
To start I of course removed the factory R2 and driver from the pill, that simply unscrews from the head.
For my Led I chose the 4500k neutral white SST-50 from Avnetexpress.com
I don't like using bare emitters unless I have no alternative. I just don't think even the best heat sinking with thermal compounds compares to the fast acting heat dispensation you get using a star. Since the only SST/R-50s I could find were on 20MM stars too big for this type of project I had to improvise.
It just happens that thermal and electrical path of the SST-50 is identical to that of a Cree XRE, so I removed a damaged Q3 from the board and used that.
(The board I actually use was in a bit nicer condition than the one pictured, but I didn't decide to do this thread until after I had assembled it)
I didn't have any solder paste at the time, but no matter. Just put a very small amount of solder on the pad and + - connects under the led. All you really need is enough to cover it with a thin layer. Putting solder on the led is unnecessary, and it may cause the led to be raised off the board slightly. I did however put a tiny bit of flux on the led before adhearing it to the PCB.
Next simply clamp the PCB in a way that it will not loose heat quickly (ie don't just clam it in the vice) Align the led, then heat the board. For this I just used my soldering iron. Its a fairly hot iron so it wets the solder on this tiny board quicly.
As soon as the solder melts, I quickly remove the heat and touch an ice cube to the bottom of the board so that the led does not stay hot any longer than needed.
If you don't have a soldering iron that will melt the solder quickly, another way I have done these for larger thick PCBs is to clamp some wide aluminum flat bar into the vice, set the PCB on top of that, and then heat it from underneath with a propane torch.
Once this is done just glue the led to the heat sink with a thin layer of Arctic Alumina or Arctic Silver epoxy.
At first I decided to install a 3 mode MCE driver from Shiningbeam thinking that 2.5 amp would be good enough for a high. This failed to please me for several reasons I will explain. Even after letting the light run what I thought was long enough to do a "burn in" a few times the output just did not impress me.
So without much hesitation I decided to go direct drive with it. This proved to be slightly better, but still not what I expected, even on an IMR cell. I took some measurement from the tail and found that I still was not getting the current I needed to the led. Wanting to see just how hard I could drive this thing, I series connected 4 fully charged Duraloops and connected them to the light using my DMM. I figured that with that much extra voltage I could power through the extra resistance of the DMM to at least find out how far I could push the emitter.
When I touched the DMM lead to the final connection it instantly jumped to 4+ amps and then in a few seconds climbed higher, and higher to about 5.86 amps where the soft yellow light began to shift to a light blue, where I disconnected the power. Now that I knew the heat sinking was adequate for the current it was time to get there using one cell.
At the time I was using a forward click tail switch that I got from Shiningbeam. This switch was a great replacement for the factory switch when I used if for XPG applications, but for the 5A drive of an SST it proved to be flawed. Guessing that this was my weak point since I had already beefed up the top end to DD using 22g copper wire, I proceeded to mod the tail cap.
At first I just wanted to see if it would help so I removed the switch, and just threw in a chunk of solid aluminum, on one regular 18560 the light was clearly brighter and the color of the led had not yet shifted to blue. Immediately after I slipped in and IMR cell. With the light already warm from the first test the color of the led INSTANTLY became nasty blue/purple😱. I could hardly get the cap off fast enough to save my precious led. Fortunately as I mentioned before these led are far more robust than the MCE or P7. I think had I put that much current through one of them I may have been looking at having only 3 or 2 dies left if any at all.
Since I now know where the problem lies its only a matter of fixing it. After some deliberation and a few attempts at some other stuff I decided the best thing to do was to mod the cap to a twisty.
Here is what it looked like.
I removed all the parts in the center leaving only the aluminum core, and replaced the feeble spring and other stuff with a solid 3/8" aluminum rod.
Basically what you want to do is replace the amount of metal on the left with the amount of metal on the right :naughty:.
This rod fits almost perfect inside the hole in the center. Next rather than trying to mash or wedge the rod in to get a tight fit I use something I think is a little know secret to weld it in place.
Yep that's right using my propane torch and a rod of HTS-2000 you can weld aluminum. Its not quite as easy as it looks to form indestructible bonds as show in some of the sales videos, but it does work.
I don't know what kind of resistance this stuff has (probly not bad since its an aluminum alloy), but since the alum rod is touching the base of my switch core for this application its a non issue.
So now here is the new vs old.
A quick check with the IMR cells shows that we still get a very quick color shift with this new tail, probably running upward of 6+ amp since the shift at 5.8A was light and gentle, and this is quick and severe.
This brings us to the next obstacle. A standard 18650 still will not drive this to the edge of color shift where I want, and an IMR gets it there far too quickly, so time to build a driver
.I just love the 7135 chip type drivers because they are cheap versatile, and easy to use. I ordered a 10 pack from Kaidomain. I use to wish that they would sell a smaller pack, but after having used several of them I am glad I got 10. Lets get started.
The first thing you will need to do is remove the Vdd pin from the boards and replace it with some fairly thick wire. I use 22g for this entire project.
As you can see the board on the bottom right still has the pin I am speaking of on it, and the other three have a silver wire soldered in place of it. I always remove this pin now because I have had trouble using a stack of these in parallel with it in place. However by doing this I think you loose the reverse poll protection provided by the driver.
I wont go into a huge lot of detail about assembling this stack because there is already a lot of info on available on the forum about it. I will say that basically what you need to do is connect all the pos legs, all the neg legs, and all the ground. Each chip has 3 legs and a tail. If you look at the chip with the 3 pins facing up, the pin on the left is POS the center and the tail are ground and the pin on the right is Neg.
I assembled the first two boards back to back with the pos connection running through the center attached to each board.
I then cut a groove with my dremel right behind the tail of the 2 ground pins and soldered them together. I also cut a groove for the parallel neg connection. Parallel neg can be made either by a jumper wire from the right leg of one of the pins on the top board to the right leg on the bottom board (just make sure you get the correct leg), or in this case I used the silver dot that would have been the led neg on both boards. I then added a 3rd board to make the current limit on the driver 4.2 amp.
This final board will face the battery for the pos connection.
Since I accidentally broke the little brass ring that the driver usually solders to I took this as an opportunity to beef that up as well. I used what I think was a 1/2" copper pipe coupler. I just cut a ring off, and narrowed it to the proper circumference. Then soldered it to the top of the driver.
Next I pressed it into the base of the pill, trimmed the wires, and soldered them to the led.
The extra length of the new driver eliminates the need for a spring, and also gives the battery something firm to press against, which works better for the twisty tail cap.
When I re-assemble the light I like to use deoxit gold on all the metal to metal contacts. Its good to lubricate threads, but mostly I use it because it has been proven to lower the resistance between electrical connections.
One final thing I will mention before we go to the beam shots. I have a strong dislike for battery rattle, so I added a plastic ring with a rubber base to the tail cap. It sits just above the base of the neg post. This prevents both the rattle, and more important it disables the light from coming on accidentally even for a moment.
Well guys all this threading has made me a bit tired :tired:. Think I'll just skip the beam shots and leave it at that....
:nana: Just kidding 😀First up DX 2AA light
XPG R5 @ 1.4A from Solarforce L2
EDC SST-50
DX 2AA
XPG R5
EDC SST
DX 2AA
XPG R5
EDC SST
On a wall
DX 2AA XPG R5 EDC SST
I hope this thread has been fun and informative. Thanks for looking.
At this time I would also like to thank the other members who pioneered the effort with this driver, and helped me to understand its true nature. Thanks to Netkidz, ti-force, Der Wichtel TorchBoy, and all the many others who took the time to help me learn to get the most out of it.
I would like to send shout out to Techjunkie for his research and documentation on the subject of DMM resistance and color shift of the Luminus Led.
I have always been suspicious of the readings given by a DMM especially in high current situations. I wandered how could all that current pass through the tiny pin points of those leads. Any way in his youtube video he presents what I feel is compelling evidence that this is true, and also offers a simple solution to aid in getting a more accurate estimate of current flow. Thanks Techjunkie:thumbsup:
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