Apparently I'm a principal person, I bought this Bestfire 9-led light last year may from dx and upon finding that the leds were not the promised XP-L but some chinese junk leds, I went to great lengths to get the light returned and get my money refunded . Then a few months later I bought it again to be used as a host. and today I did the mod, my first soup can mod! 
The host is neat and well-arranged, lots of opportunities to improve it, with everything accessable: better leds, thicker led-wires, bypassing the R100 resistors before the FETS, bypassing the bottom battery springs that are easily accessable. One improvement was already done for me: the one FET-driver of last may has become a two-FET driver in last november's copy, ledwires were also already a bit thicker:
Left the one-FET driver, right the two-FET driver (note the R100 bypass with piece of copper already done)
I first started with replacing the leds, this was going to be a 385nm mega-flooder. I bought 10 LG 3rd gen. 385nm leds on Aliexpress for this mod. I want 1A max per led (for a test of this led on a copper board, see http://budgetlightforum.com/node/43390 ), so I did not bother with copper boards. I love watching reflows so I made a video of the swap, it took longer than I thought, I did not realise that 9 leds is quite a number to replace:
It worked first time, jay!, so I was very curious of the ledwire current in the further stock light. I love my new clamp meter for the ease of use . I got 4.67A already on four NCR18650BD batteries, that is 500mA per led, not bad. I had to add blobs of solder on top of the batteries to have them make contact to the driver:
Then I bypassed the two R100 leds on the driver that were in series with the FETS and the current went up to 6.42A, 700mA per led. Then I replaced the ledwires with 18AWG silicon wires and got 8.6A, almost 1A per led which was the goal, any higher I would not trust without DTP copper ledboards. No spring bypasses needed
Now it appeared that when closing the head, the ledboard by a hair does not touch its shelf on the host, the board-reflector assemby hangs on the outside of the reflector. So a spacer was needed to get the ledboard touching its shelf. I do not like to use chunks of copper, but I did not have anything else than copper. So enter the (modest 1mm thick) copper disc:
Sanded, holes made and attached to the ledboard (no thermal paste):
A tiny bit of thermal paste was applied on the shelf to make good contact and everything assembled. Done:
The light projected on the wall with a (overhead projector) lens:
It is a LOT of UV-light:
So now what to do with it?, dunno, it was fun to make. Perhaps Hestbech, if he reads this, would like to try it for his amber-searching?
Anyway, I ordered another one of these hosts for a mega-warm-white-flooder 
Thanks for reading.
Nice. Going by the beam shot it doesn’t look like it would benefit much from a lens filter -http://budgetlightforum.com/node
Haha, that looks freakin awesome.
WOW.
CSI here we come .
What I do
Oh man. Does the bounce-back from white walls hurt your eyes at all?
My Favorite Modded Lights: X6R, S8 , X2R , M6, SP03
Major Projects: Illuminated Tailcap, TripleDown/TripleStack Driver
awesome, that projecton, try sell it to a museum!
It is done when it is done
How my BLF Specials generally work, please read before asking Qs
The Q8, Exciting a groupbuy for a Premium BLF special high lumens soda can light!
The GT, A BLF special GIGA thrower
The FW3A, a TLF BLF special small, elegant, powerful triple
Lithium Ion safety 101 important read
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Sweet build. Now if a vendor would make an affordable filter that fits that light, a new trend in UV flash lights will started.
Nice. The overhead projector beam shot is crazy.
The use of a filter for 365nm leds is to filter out the white light that the leds produce as a by-product, the 365nm light is completely invisible.
385nm leds is a different case, there’s no white by-product (which is a good thing), what is distracting is the 385nm light itself, your eyes are slightly sensitive for it and with these high outputs it is clearly visible as a purple glow. You’re not going to filter that out because 385nm is what the led is about. You can use yellow glasses on your head when using this light, it will remove the purple glow, but also makes the world a bit yellow of course
BTW, I use polycarbonate safety glases with this light, my eyes would be dead without them. Yellow glasses are even more friendly for my eyes.
link to djozz tests
Nice, a high powered UV light! Makes me want to build my own, but only in a triple form.
USB power meter/tester thread
You’re right. I was shamelessly plugging a product request to gin up demand for such a product. I would like to make a 365 UV flooder with my 10 budget 365nm emitters I already have.
Are you certain that the new driver is not a buck driver? (and maybe the old driver too?) The new driver appears to include a large coil, a large capacitor, sense resistors, and two DPAK items. Since diodes are available in DPAK layout the driver could easily have an FET and a diode on it. Together a buck controller IC, this completes the list of normal parts included with a buck driver.
See ImA4Wheelr – Driver Info: HX-1175b & HX-1175B1 (Pic Heavy) for another example where we initially thought there were two FETs but it turned out (post #8) that it was a diode and an FET.
Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)
I only know some driver basics so I could nevertell anything for sure , at least the batteries are parallel and the two ‘FETS’ are wired in parallel, with the two R100’s between ground and what I assume is FET-source, the FET-drain is the led-minus, the thorroid is connected to led-plus. So I assumed that it is direct drive, and I vaguely remember comfychair adding a thorroid to a direct driver as well for some reason (suppress nasty spikes?). I closed the light up for now, but I’m prepared to open it again to make better pictures of the driver if there’s interest and it helps understanding what is going on.
Btw, it is a simple high, low, off driver with low frequency PWM, electronic switch and a small green on-led in the switch. I like the simplicity of it but it is not anything advanced.
link to djozz tests
Don’t bother opening it up for that reason. We already understand how the inexpensive Chinese buck circuits are laid out, so if it’s one of those we wouldn’t learn anything.
If the FETs are truly wired in parallel and there is no schottky diode then it is certainly just an FET/DD/PWM driver.
The inductor/coil does help with spikes. We’ve seen single cell drivers constructed both ways. (The initial 3-toroid SRK drivers were in fact buck setups for example.)
Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)
Awesome mod Djozz, what a crazy flashlight. Your hands shake almost like mine
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Courui D01 -Mod ZY-T08 Small Sun -Mod Shadow JM30 Mod - copper edition Brinyte 158B mod - copper brass hybrid
Small sun ZY-T08 Mod II - The Next Generation Small Sun ZY-T08 Best Of Both Worlds Warsun X50 mod - a complete makeover
Maglite 3C Mod - old school style
Thanks! I hope you will never find my first BLF reflow video, let’s say that I am extremely steady now. :-/
link to djozz tests
That thing looks like it would produce an instant headache
Nice build
Thanks djozz. Nice mod as well as a very good video on reflowing multiple leds. Is there a thread on your little home made hot plate?
djozz quotes, "it came with chinese lettering that is chinese to me".
"My man mousehole needs one too"
old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".
Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.
Thanks! Hmmmm, how I made the heatblock is in the same ancient thread as my above mentioned terribly shaky first reflow, so I’m a bit hesitant to reveal the link….., oh well, here it is, don’t laugh :-/ link
link to djozz tests
Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)
I gained just a bit more confidence in it, and that was actually a particularly ‘shaky’ day with too little sleep
link to djozz tests
Nice mod! Makes my UV-triple seem insignificant… :-/
+∞
Keepin’ the “B” in BLF
Haha, modding for fun; mod first, think about why later…
i have modded one of my 2 trustfire tr-3t6 flashlight into a warm white donut spitting 3x dual nichia 219A. I like the cheap way of modding something into a dual nichia 219A, but modding a SK98 or putting matte tape over the front glass is more suited for a dual led board…
I love it djozz. Now I want to make one too. Like you, I don’t know what I’d use it for, but it’s neat.
Any recommendations for UV emitters for me to try?
There’s a few considerations. I was thinking 365nm emitters first, but I did not dare that because it is more dangerous and more invisable. and then I would like a UV-pass filter to complete the build and a 60mm (or what is it?) ZWB2 filter is very expensive. And I would like good quality 365nm emitters and 9 of them are pretty expensive. So 365nm was out for me.
And then I found these LG 385nm emitter for cheap ($2 per led, so $18 worth of leds) on aliexpress, LG is a decent brand, the leds are a fairly recent model (but not the latest from LG) and 385nm was something I had not tried before.
But this would make an impressive light too with 400nm leds. You need 9 of them, and of 3535-size to make it possible to use the stock ledboard. See if you can find LG-leds or a somewhat decent chinese one.
If I would have a buyer, I could build one with 9 of led4powers 365nm leds and one big ZWB2 filter, it would be a $200 build. I guess it would be a forensic scientist’s wet dream.
link to djozz tests
Very interesting project :GRADE: :GRADE:
I am new to this world of modifying flashlights. I have a question:
The paste you use to lubricate the LEDboard – the 9 locations where you took LED emitters of …. is it a form of conductive glue instead of soldering, which also can detach again when you heat it up? ??(I can see that you put your LEDboard up on the heating element again and adjust the LED emitters subsequently) Please link to the product. It must be found here in Scandinavia also
Regards.
Michael L., Denmark
interested in making my own very powerful UV flashlight in the range of 395 - 410 nm. My future goal is to make a UV flashlight of 30w or more ...
Hi Michael, it is no glue, it is solder paste: a mixture of fluid rosin and tiny 63/37 Pb/Sn solder particles, it works just like normal solder wire. This paste is standard when reflowing SMD-components on circuit boards. I got mine from Fasttech, it is really cheap stuff: https://www.fasttech.com/products/0/10003546/1261003-chips-repair-tool-s...
link to djozz tests
Thanks a lot
Regards
Michael L.
interested in making my own very powerful UV flashlight in the range of 395 - 410 nm. My future goal is to make a UV flashlight of 30w or more ...
I need one of those for scorpion hunting here in Arizona. How much did that cost you to build?
Host: $29
Leds: $20
18 AWG Wires:$0.10?
link to djozz tests
Wow that’s not bad for the ultimate scorpion hunter!! Thanks for the idea and the info.