TCSS Tri-Cree burn out

[Kyphotic_Jedi]

I purchased a RB/B/W tri-cree recently to go in the graflex 2.0 run by a NB 3.0. The install went well but after a week now my blue cree is toast. RB is still hanging in there as is the white flash. I used the on board drive adjustment based on the royal blues 3.41 meaning that the regular blue 3.47 should be under driven slightly. I checked my math now for a third time after the burnout and all was good.

This is my first time using the tri-cree because I have more experience with tri-rebels and have never had a problem with them but everyone has been going cree so I tried something different for this build.

Notes. Leds RB/B wired in parallel, aluminum heat sink, TCSS tri-cree, drive adjust to rb.

In my own attempts to troubleshoot I am concerned that the led may not have been 100 percent flush with the heatsink. It is not a TCSS heatsink that uses pressure to hold the led in place and when I dissembled it, the led pad was slightly loose, but I am not sure if this was caused by assembly or disassemble. If the former is the case I suppose the pad could have had a space in between it and the heatsink and overheated but would it not have blown both leds?

What do you guys think, was it just my unlucky day? I'm probably gonna go back to Rebels, i just don't want to blow another led. Any suggestions or advice is greatly appreciated.

[darth_chasm]

Have you successfully done the same set-up in the past? Two leds with different characteristics driven by the board in parallel?

[Forgetful Jedi Knight]

Welcome to the Forums.

You really should use resistors. You probably blew out your Blue. Parallel wiring the way you did it only works if you are using the exact same LEDs, and even then you should still be using resistors.

[Big_Furry_Oaf]

Parallel wiring the way you did it only works if you are using the exact same LEDs

Oh dang this kind of threw me.
I recently wired my tri-cree similarly. 2 Rb's and 1 white in parallel through a NB3.0 board, 3.7v power source. I used 1 ohm 2w resistors on the negatives of each led but after a few activations it blew the white.
So the mistake may be wiring led's with different colors in parallel?
It's late here and I'm kind of fuzzy in the brain... thing... right now.

[Kyphotic_Jedi]

Have you successfully done the same set-up in the past? Two leds with different characteristics driven by the board in parallel?

Yes. Once. I used a rebel b/w/w with b and w in parallel, underdriving the blue to mach the white. I have not had any problems with it.

[Kyphotic_Jedi]

Welcome to the Forums.

You really should use resistors. You probably blew out your Blue. Parallel wiring the way you did it only works if you are using the exact same LEDs, and even then you should still be using resistors.

Yes FJK. I know this is not the greatest policy and surely others should not follow in my footsteps, I just have had no issues in the past. I usually only use resistors on reds.

As far as wiring in parallel, if the blue is underdriven to match that of the RoyalB, why would it blow and not the RoyalB? Forgive my ignorance. I have had success with this concept in the past.

I guess my thinking is that, had iI used a B/B/W, (without resistors) but had set the drive for under its draw, in theory I would have two blown leds now? But for what reason? If the drive settings are not that effective, why make it available at all? I'm rambling.

( I do understand the moral of the story is to use resistors FJK, I'm just trying to talk it out so I can wrap my head around it.)

And how do I wire a rB/B/W if not in parallel to nb3 even with resistors? Series wouldn't work. Seems like Parallel with resistors on the negative wire? This has really kinked my mind.

[NanoRex]

The main issue here is that you have two different LEDs wired in parallel. They have different specs, so the circuit becomes pretty unpredictable and it's likely that one will hog much more current than the other. If you had used a BBW or rBrBW, you'd probably be fine. You need one resistor for each if you want to wire different LEDs in parallel.