Hello, I am new to this form. I joined because I need some help with this newest project.
Its purpose is to be a portable video light (as I am a videographer)
Power: 18650 cells 5p5s configuration, recycled cells, gives me about 160WH when discharged at about 3A. There are 2, 24v-12v (adjustable) voltage reducers, each are good for 9A. Then a motorcontroller to give me 9v-12.5v adjustability.
LED's: 4 XHP70.2, 4000k, 80cri 12v. Which I have free flow-soldered onto 12v ebay 16mm copper PCB's as well as some 6v 20mm PCB from adventure sports flashlights (these 2 were wired in series in order to let me use the 12v system already in place)
Thermals: Using Arctic Alumina Thermal Adhesive to connect PCB to heatsink. Heatsink is a water cooled block, connecting to a 80mm radiator (ya its kinda small) with a 80mm fan blowing pretty hard, then back to the 3gal/min pump. I connected everything up underwater so that I would not need a reservoir.
The Problem: The LED's keep dying, well stop working at least... I really do not think this problem is due to thermals. My reasoning for that is i've run all 4 (for the short time they worked) at full power 10-11amps for about 15 min. Everything was fine except for a small amount of flickering from one of the LEDs. I then turned the light off, waited a while, turned it back on and within about 5 seconds the one LED that was flickering shut off completely. This then happened again with the 2 wired in series (on the 20mm board) but after about 2-3 more tests. (they both went out at the same time)
What I think might be the problem: It seems to be something with the electrical connection to the PCB, I am no expert at soldering but at the same time I am not bad at all. The connections were all strong, but when I took off the little lenses and desoldered the wires connected to the PCB a little copper piece came up, out of the PCB. And now I cannot solder to the PCB at all.
Other possibly useful information: After the PCB or Led stops working, if I put power to with just a power supply (after desoldering everything else) It lights up super bright, but taking a closer look through some welding glasses I see that only half the LED is lit, turning the power down to 5.5v and same thing half the chip. Again this only happens after they stop working When tested before insulation it works perfectly, and when installed it also works perfectly, only after it goes dead and I desolder it from the light does this problem happen. I am using a small amount of E6000 glue to mount the lenses to the PCB/LED also a small amount of hot glue. I learned my lesson with not using superglue next to the LED already.
Any help, suggestions, recommendations, (good place to get real, solid PCB) etc.
Thank you!
P.S. Cant quite figure out how to post pictures, so here is a link to a google drive folder with a couple pictures of the light in it.
https://drive.google.com/open?id=1qU_U_HMjId7iZ5iUnovlc9uplTUficiM
Its purpose is to be a portable video light (as I am a videographer)
Power: 18650 cells 5p5s configuration, recycled cells, gives me about 160WH when discharged at about 3A. There are 2, 24v-12v (adjustable) voltage reducers, each are good for 9A. Then a motorcontroller to give me 9v-12.5v adjustability.
LED's: 4 XHP70.2, 4000k, 80cri 12v. Which I have free flow-soldered onto 12v ebay 16mm copper PCB's as well as some 6v 20mm PCB from adventure sports flashlights (these 2 were wired in series in order to let me use the 12v system already in place)
Thermals: Using Arctic Alumina Thermal Adhesive to connect PCB to heatsink. Heatsink is a water cooled block, connecting to a 80mm radiator (ya its kinda small) with a 80mm fan blowing pretty hard, then back to the 3gal/min pump. I connected everything up underwater so that I would not need a reservoir.
The Problem: The LED's keep dying, well stop working at least... I really do not think this problem is due to thermals. My reasoning for that is i've run all 4 (for the short time they worked) at full power 10-11amps for about 15 min. Everything was fine except for a small amount of flickering from one of the LEDs. I then turned the light off, waited a while, turned it back on and within about 5 seconds the one LED that was flickering shut off completely. This then happened again with the 2 wired in series (on the 20mm board) but after about 2-3 more tests. (they both went out at the same time)
What I think might be the problem: It seems to be something with the electrical connection to the PCB, I am no expert at soldering but at the same time I am not bad at all. The connections were all strong, but when I took off the little lenses and desoldered the wires connected to the PCB a little copper piece came up, out of the PCB. And now I cannot solder to the PCB at all.
Other possibly useful information: After the PCB or Led stops working, if I put power to with just a power supply (after desoldering everything else) It lights up super bright, but taking a closer look through some welding glasses I see that only half the LED is lit, turning the power down to 5.5v and same thing half the chip. Again this only happens after they stop working When tested before insulation it works perfectly, and when installed it also works perfectly, only after it goes dead and I desolder it from the light does this problem happen. I am using a small amount of E6000 glue to mount the lenses to the PCB/LED also a small amount of hot glue. I learned my lesson with not using superglue next to the LED already.
Any help, suggestions, recommendations, (good place to get real, solid PCB) etc.
Thank you!
P.S. Cant quite figure out how to post pictures, so here is a link to a google drive folder with a couple pictures of the light in it.
https://drive.google.com/open?id=1qU_U_HMjId7iZ5iUnovlc9uplTUficiM