I just finished my latest build…and it’s a monster! I had seen Matt Smith’s original build on YouTube with a CBX3590 in a BLF GT (I can’t find ANY other example of anyone building a light with a CBX3590 in it either) and thought I could probably do it better and in a smaller and lighter package and actually focus the light too. For my final version I bought a Cree CXB3590 from Digi-Key and fit it into a Trustfire TR-J18 host. For a driver I used a Task LED “Ultraboost” DC boost driver which is a brand new driver for 2021 that handles more current than the original Hyperboost could! Underneath the factory aluminum plate the LED is mounted to there is 3/8” deep slug of 1 1/2” diameter solid copper to help carry away the heat and transfer it to the aluminum body of the head of the light. Fitted to the end is a 57mm collimator lens with a very short focal point which perfectly focuses on the CXB3590 and keeps the light in a nice tight focused output instead of a sloppy flood style output I have seen on other attempts with this emitter. I have ran the light at a full 38v @ 3.2a but decided to dial it back a bit for greater efficiency and settled on 36v @ 2.8a instead. The driver is fitted nice and low in the head with the positive input wire soldered directly to the spring top of the TR-J18’s original driver board which I stripped down bare to supply power to the driver. I also spring bypassed the tail cap switch spring with copper braid and soldered the brass pill directly to the spring and copper braid that goes down to an Omten clicky switch. For cells, I’m using 4 Efest purple IMR 26650 (50a 4200mah) cells and one additional battery extension tube. I might put in another extension tube and run 5 cells, but so far so good with the 4 cells. The driver has an aluminum heat sink of my own design and I used a section of a prescription pill bottle (perfect fit) around the edge of the driver as extra insurance against shorting it out! The 57mm lens I found on eBay for 15.00 that came with a kit of a reflector, fixed bracket, and lens for a 30w LED and has a beam angle of 60-80 degrees. The focal length is super short and looking down at the emitter all you see is the emitter surface itself perfectly focused! The lens doesn’t pick up anything beyond the edge of the emitter surface itself, so no visible wires or surface area. Nothing but focused light here! I polished out the inside of the head surrounding the emitter for good measure. I will say that this thing greatly outperforms the one Matt built in the BLF GT with the lens in use. Super tight output with zero spill and an absolutely uniform amount of light intensity across the beam pattern. The driver pulls 7.6a at the tail cap….well within the 10a rating of the Ultraboost driver and would be reduced even lower if I used a fifth 26650 cell but my extension tube I ordered isn’t here yet and four cells seems plenty long already. This LED makes quite a bit of heat! Keeping it turned down to 2.8a helps quite a bit. Thanks for reading! Andrew
Groovy! Build photos and beam shots you can, please. I’ve been musing over a project like this for 2 years. I have a host and some of the bits, but not the funds, motivation nor time at the moment. Mayne you’ll inspire me. I am looking for sustaining 10k lumens for 10 minutes, amd the cxb3590 with a cc/cv driver and 8S GA’s is one way I can do that.
I used Noctua NT-H1 paste and a VERY tiny ribbon of thermal glue around the edge perimeter to seal it in and hold it in place without having to use screws. I then placed a heavy weight on it overnight while the thermal glue cured. The aluminum plate it sits on is threaded in place and the contact surfaces are all coated with Noctua paste too and de-anodized clean as well. The large copper slug is bonded to the underside of that aluminum plate in the same fashion and method that the emitter was. Works quite well and no thermal issues to complain about.
Hmmmmmm Robin Dobbie, I guess I could try taking some pictures here with both the lens in place and after removing it too and see the difference. I just thought that controlling the light output was desirable opposed to a giant flooder of a light. Give me a few hours and I will share the results with you on that! I don’t have any type of a reflector in the light other than the polished surfaces surrounding the emitter. Every reflector I found was giant and would look ridiculous in the host.
Same LED, same current?
Tiny differences like AR coating or lens absence aside, they should be exactly the same. After all spill is the light that goes from the LED directly towards the lens without ever touching the reflector. Exactly like with mule.
I built a COB 100w one and the spread, even with the narrowest aspheric I could get was still bad, so I put a reflector over the lens and that helped some, but still not the greatest. There is one of those focusing/shallow reflectors that goes on the COB itself, so that probably doesn’t help. Overall, COB do not equal throw…just massive flood unless you properly focus it with wother a lens or reflector.
Nice powerful flashlight! I like to see more flashlight built with COB, but I think I prefer the beam shot with reflector instead of glass lens. It will be nice if you have simple comparison photo with ‘regular’ flashlight that people here are familar with so we can have idea of how bright this is. Good job!
