I went ahead and opened up the Kaidomain P-60 drop-in. They had an R150 current sense resistor on the buck driver, so I stacked an R056 on it. Put it back together with 22ga leads (it had like 28 ga)
Where it was pulling 300mA at the tail, it’s now pulling 470mA. And is considerably brighter!
You write in such great detail and clarity about the considerations you make underway during your testing that it is always i pleasure for me to read these tests.
I have way more time to think of what I am going to do for the hobby and how and why, than I have actual hands-on time for testing and modding, I think that you can find that back in the write-up as lots of thoughts and considerations about what I did.
I would love to see how the KD P60 drop-in (with two cells) compares against the two emitters in the OP. The KD drop-in (two emitters under one dome) already works significantly better than anything else I’ve tried, and if the two in the OP work even better still, that’s pretty exciting.
Those UF-602C hosts are great for small mods and I’d love to use one for UV instead of the relatively huge SF-L2m I’m using now.
UV-leds have neither the power nor the wavelength to be the least effective in killing germs. UV-cfl tubes and other UV-sources have way more power and go much deeper into the UV-spectrum. Leds become only interesting if a directed beam is needed, cfl tubes can not do that.
No, the Ledengin shows a shift of a whopping 0.3 nm when going from 400mA to 1000mA, I'm not sure if anyone is concerned by that ;-) .actually, temperature has a considerable larger effect: 3nm going from 20 to 85degC.
This chinese led surely will have other characteristics, but I would be surprised if the current->wavelength shift will be disastrous.
But apart from this, why run it at 1350mA ? Stick to 1 amp and you are almost at maximum power, you just make heat with the last 350mA (and stress the led unneccessarily).
If you refer to the KD drop-in that DCBstm posted here above somewhere, with the two die's side-by-side, this led will perform better already if only because it is a single die that will have a better beam, even in a small reflector. But I would think that the output is also better because it is a more modern led: the datasheet is from 2012, the two-die led from KD has been around for much longer.
The 16340 host is not the UF-602C host, but it is noticably smaller, and of better quality. It is this flaslight, unfortunately sold out at Fasttech. The 2x7135 NANJG driver came with the stock light :-)
Images taken with Canon 20D, in RAW, Manual mode, on a tripod, 1 second f/4.5 at ISO100. 10’ from bookshelf to camera sensor. No sharpening or any other adjustments applied, RAW converted to JPEG for sharing.
Base image with Auto settings and shot in JPEG
The Kaidomain drop-in is less bright with mutliple cells, the driver cuts the amperage the higher the voltage is to maintain a constant output current. I’ve tried it with as many as 6 cells (hope I’m remembering that right, I used 18500’s with multiple extension tubes on an L2P) directly comparing output from 1-6, 1 being the brightest in overall output.