BIG KD driver questions... TR-J12 / J18 mods?

The LED's in the TR-J18 are in parallel like the other multi emitter trustfire lights

How about the J12?... is it series or parallel wired? On the KD forum theres a comment made by one member who managed to use the 5x board in his J12. He didn't elaborate though on the LED wiring. I guess it wouldn't be too difficult to re-wire them in series, provided theres enough room behind the reflectors for the wires.

Take out the two screws in yours and you tell me

You could measure the voltage on the wires going to the head, if it's 3.x they are in parallel, if it's 15+ they're in series.

Yeah another member did that with his J12. They're definitely wired in series in the J12.

Well then get to modding with the Beast Driver :smiley:

I would make double sure first

Unless I'm missing something don't you just wire them up?

You can parallel wire any number of emitters, odd or even. It doesn’t necessarily make sense due to the varying Vf per emitter which can cause current hogging, but it can always be done.

I would double make sure the drive will fit and is a simular size is what i ment as its not a cheap driver. You can parallel wire odd and even numbers.

I posted detailed measurements of the 9xLED KD driver in another trj12 thread

Hi all:

Can some kind soul put up some pics with instructions on how to swap the driver out of the TRJ12 with the improved one from KD? Soldering rookie here that has absolutely no idea about electronics.

Thanks.

I started this thread little while ago, just to scope out a mod for my aliexpress J12. Out of the box stock, my light at 8.4V pulls around 28Watts, and delivers ~1.35A to each LED. The T6 XML will emit ~475 Lumens at 1.35A, for a total of 2375 bulb lumens. It gets warm at the 5 minute mark and needs 8-9 minutes before it reaches "hot to the touch" state. It needs another couple minutes to reach "painfully hot" to the touch. These numbers extend a little if I hand carry the light, with air circulating. So the stock driver is a moderate driven design, I think the sock light is a well thought out balance between output, thermal stability and power consumption.

According to KD specs (which look accurate) this new driver will pull ~55 watts. Factoring in an 80% efficiency (typical for FET-based drivers), this driver should deliver 44Watts to the 5-XML array. That equates to 8.8Watts & 2.6A into each LED. The T6 XML will emit ~800Lumens at 2.6A, for a total of 4000 bulb lumens.

Benkie and I have had some excellent J12 discussions in his "calling all J12 owners" thread here...

https://budgetlightforum.com/t/-/8573

...Where his light draws 55W at 8.4V and pushes his LEDs hard at ~2.5A each. So I think Benkies J12 is a good approximation how the J12 will perform with a ~55W driver upgrade. The idea of HOT 18650 cells (being pushed at a ~6.5A draw) and a HOT heatsink after a couple minutes, doesn't really appeal to me that much. I generally use my J12 as a constant ON, task flood-light kind of thing. So for me a cooler running ~2000 Lumens is very nice. Now if I could re-flash this KD driver to add another medium-high output mode at ~60%, and set the PWM frequency higher that would be really nice.

I would consider 5-XML pushed with 2.6A each more of a short burst only kind of light, like the DRY Turbo.

Question to others regarding 18650 safety.... how safe is it to run two cells in series with a ~6.5A current draw? Is there increased risk of a flame/vent incident using 18650 cells in a ~2C (+) application?

thanks!!!

Ask at KD, they might reprogram new one for you. They did it for me for tripple XM-L. Not exactly they way I wanted, but still got 4 modes and no strobe/sos ;-)

Greetings, this is my first post, but have been watching for some time. I did the conversion using the KD 5 LED driver a month ago. The biggest problem was the circuit boards were very slightly larger than the allowed opening on the light. I gently filed the diameter down and got it to fit. Overall the light operates pretty good. It's definitely brighter than my DRY in Turbo mode. I'm measuring 17.2 volts at the head. I didn't change out the switch. I figured I'll just replace it if it goes. I'm using 3 batteries. With two batteries the output is visually less.

Cheers

Hey thanks for taking the time to reply and welcome to BLF!!

How hot does the light run at 8.4V?... would you say its "painful to the touch" hot in 1-2 minutes or does it need more like 5-6 minutes to reach that level? With 2 cells on HI, could you place it on a table and leave it unattended for 5-6 minutes? If its visibly dimmer and cooler running with 2 cells then thats a big plus for me.

Also how is the PWM at lower modes? is it visible at all?

thanks again!!

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.