Rewiring Luxeon 3-up Series => Parallel

Flashlight Modding and DIY Parts
1

I’ve mentioned the Luxeon 3ups that are on closeout at ledsupply.com in several threads (just bought some more :laughing::

http://www.ledsupply.com/07007-pw740-l.php

As they come from ledsupply, the emitters are in series, which means that, to drive it, you need to have a driver that can supply 1 amp at ~9V.

One driver that will do this is this one from CNQ:

http://www.cnqualitygoods.com/goods.php?id=1391

but that driver is a double-board with a smaller board and an ~20mm battery-side driver, which is hard to fit in a lot of lights with smaller, e.g., 17mm drivers.

I had been hesitating modding the ledsupply 3up to parallel, because it looked like a painful job, but I finally started doing it a couple of weeks ago, and it’s not that hard. Basically, you have to just remove the 3 0-ohm resistors (I use a heatgun, and they just pop off, and then I grab them with some tweezers), then wire all the + pads together, and all the - pads together.

To do the wiring, I first jumper between 2 + pads, then jumper from one of the+ pads to the next, and then do the same thing with the - pads.

The result is that you end up with a parallel 3up that you can driver with a “normal” driver, e.g., any of the 7135-based drivers. 2.8 amps is probably the minimum current you need, but you can go from there upwards. Since the emitters are in parallel, whatever current the driver supplies will be split into 1/3 for each emitter, so 3 amps => 1 amp per emitter.

Another member asked for some pics, and I just happen to have both an original 3up and a rewired one, so here are some pics (apologies if the soldering is not the best, and pics are a little fuzzy :():

Side-by-side:

The original Luxeon 3up, emitters in series with 0-ohm resistors:

And, the modded Luxeon 3up, emitters in parallel with 0-ohm resistors removed:

I hope that this helps…

Standard disclaimer: I am not at all associated with LEDsupply or with CNQ :)…

2

Thanks Ohaya. I guess the hard part is soldering on the driver leads without desoldering the jumpers while your at it.

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Yes, you’re right. I don’t know if I’ve been lucky or what, but I was expecting problems with that, but haven’t had any. What I’ve been doing is cutting the jumpers to the length I need, and stripping the ends, fluxing the ends, then soldering, one-at-a-time. After I solder one end, I try to bend the wire so that the other end touches the glob of solder on the next pad, etc. by itself, i.e., so if I don’t hold the loose end, the wire still stays near or on the next pad.

I’ve been using silicone 26 AWG wire for the jumpers, which doesn’t really “hold the bend”, and keep thinking to try some teflon wire, but teflon wire is so stiff, I think that it might be counter-productive.

Similar to stacking 7135s, I think… Practice, practice, practice…