Actually the light functions better with 2 cells verses three. Even the KD spec states to use 2 cells. Anyway I don't detect any PWM at the low setting at all. As far as heat build up, I'll have to check that out tonight and see what I get.
Cheers
Welcome to the club, brightlights!
Aloha and welcome to BLF brightlights!
Is there any need to “pot” the new driver? How would one do that, just tank the driver cavity full of thermal grease or arctic silver and let it set like concrete???
brightlights: Can you clarify if the new KD driver runs better on 2 cells or 3 cells because in post #19 you said it runs brighter with 3 bells, but in post #21, you said it actually runs better on 2 cells??
FWIW, I will only run mine on 2x26650s anyway even after I mod it with the new driver.
Greetings, using three cells, some of the KD driver functions didn’t work, specifically the emergency flashing mode. It had no problem running in high, medium or low mode however. With 2 cells, the driver functioned just as advertised at KD. All modes including flashing. I just noticed that with three cells the high mode was brighter than with 2 cells. With regard to heat buildup, 1-2 minutes wasn’t a problem. At 5 Minutes, it was getting pretty hot. I discontinued the tryout because I didn’t want to burn things out. One other note, you can run the flashlight on medium mode as long as you want. I found the brightness to be about equal to the high mode of the unmodified flashlight. As I recall I originally was getting about 14 volts on high mode on the original light, and was pulling about the same on medium mode with the new driver.
Cheers
sounds ideal to me…
Great thanks for the feedback!! I think I’m going to keep mine stock for now. It wouldn’t take much to change my mind though.
Brightlights, do you have the ability to create regulation plots, light output measurements, current draw measurements, etc…? I’m very interested in doing the same mod, but I’d like to know more before doing so. Thanks.
Agreed.
With 8.4 volt on constant high mode, I'm really pushing the limit of the unprotected NCR18650A's panisonic cells as I'm at the maxim claimed recommendation of 2C max (6.5 amps) discharge. Ive proven in my old discharge test's of the same cells they will do 7 amps from 4.18 to 2.5 volt with out venting but they do get dam hot but with in there safely limits, but the light gets hot and the batteries are inclosed not opean like my battery discharge test.
On 26650 cells your still up around the 1.6C mark and with my protected trustfire cells going from my battery test,s i will only get around 15 Min's of constant running on high till the battery protection trips, the battery protection tripping is not an issue as i would not run the light for 15 Min's on high on 8.4v due to to much heat, but on 12.6 volt no problem as my current draw is low approx 2.2 amps.
So for short burst on high I'm not worried, but for longer runs i use 3 x protected 26650,s with 0.6C discharge with about 2 hours run time on high, this is how i normaly use the light.
Well, you could use A123 26650 LiFePO4 cells. Only 2300 mAh, but you can pull 100C from them! A 4S pack will start a car 20 times in –20C weather. I’ve also seen them charged at 100C (under 45 seconds). They also make a 1100 mAh 18650 cell. And a wicked 20 Ah pouch cell. And a few other sizes of larger format cylindrical cells.
In my case i have 7.4v 2200 40C constant lipo cells that are cheaper and i use them with my daughter for RC, they would do the trick no sweat, but on 3 x 26650 or 3 x 18650 0.6C or 0.8C draw from the light is fine.
Wow…. I want one now. 
Hi there guys I have been looking at this thread for a while and have modded my Trustfire TR-J12 with the Kaidomain 50-60W driver (http://www.kaidomain.com/Product/Details.S020417) with 100% - 75% - 50% - 30% - 5% modes and no visible PWM flicker. The soldering job I did was fairly atrocious, and I totally destroyed the original driver board with a drill (it just WOULDN’T come out the nice way…) but the mod worked fine and the light is now a total monster. The output from the light is ridiculous… it completely white-washes my large-ish garden with light, and is probably about doubly as bright as the original TR-J12. A few observations from my mod may be of use to people considering doing this:
1. In 100% mode, the torch head becomes noticeably hot around the fins after about 10 seconds, and literally burning hot after 2 minutes. Short bursts only then!!
2. In order to install the KD driver, I needed to slightly file down both circuit boards by about half a mil in order for it to fit. This may be because the retaining ring from the old driver was still (soldered) in the head of the torch, which may have made the diameter smaller. In doing this, I separated the two boards by accident and severed the connections, but I emailed KD and they sent me a diagram of which bits to solder back together.
3. The top section of the torch is VERY stiff (as I have read elsewhere) and so I used grippy rubber gloves to undo it (perseverance is key… no wait - brute force!!)
4. Both 2x18650 and 3x18650 work, as well as 2X26650 (I only have two…).
5. I don’t have any springs so I just soldered some copper braid (sold as ‘desoldering wire’) to the middle of the driver board to make a high current contact. From what I’ve read, this stuff is much better at dealing with the sort of strain this driver will put on it than a regular spring will.
6. I have literally NO electrical or mechanical knowledge and managed it so it’s a fairly easy mod and took about 1 hour in total.
All in all, the new monster really has the elusive ‘WOW’ factor and considering the price of the new driver, I highly recommend it!
I can upload beamshots or shots of the mod if anyone is interested.
Ta Da
-momentumexchange
Welcome to BLF! Yes, beamshots would be great. :D
Unscrewed the top part from the body. Seems like the threads are anodised, hence it would somewhat insulate the head from the LEDs to the body. Stock form it’d be fine, but i guess modified it would be pushing it.
Top part of the head could even heat up a bit faster than the DRY.
Thinking of going for the X100 instead. It’s bigger but seriously it’d be more practical as i don’t have much of a problem with big lights as i am used to them.
That is usd86 on one aliexpress store. (my $83 shipped deal with powerwholesale.net did not go through after they shipped Ergotelis and Eudaro’s)
It's good to have you here, MomentumExchange!
Good to be here, thanks for the welcome! 
Roger that. I’ll put together some beamshots comparing the modded J12 with a few other of my lights and report back.
Haha! I just noticed the ‘momentum exchange tether facility’ picture you posted - love it.
It sounds like you just made yourself a fan club right here. I’ve been holding off on buying any of these multi emitter lights because they are so mildly driven and that just doesn’t sit well with me (see my name & U get the idea).
This mod you have done sounds so wicked that me (and the rest of the lumen junkies here) som I am gritting my teeth in anticipation LOL! Please do share. I for one would love to see this mod done by a man who claims to have literally no mechanical or electrical skills yet has done something we have yet to see here. Well done. And have fun here. I do
OK firstly thank you for your great reception - what a great community vibe
Now down to business… I plan to take the beamshots tonight in my garden and wonder if anyone has any advice on which camera settings to use / any other hints and tricks for the best ones?? (I have a Nikon D50 …with the aperture stuck in the open position - great for nightime but daytime is another issue :/). Also, how do you create those great ‘mouse over for another photo’ images?
Cheers!
-momentumexchange