I figured while I wait for some insulating stuff I would test the driver outside the flashlight to be certain it’s not something inherent in the driver, or something of that nature.
I’ve got an old aluminum cpu heatsink just sitting about, tons of various gauge wire around the house.
So far I’ve figured out I need to screw the emitter/star to the heatsink Solder driver to the star….
where to go from there I’m not really sure. Do I solder a black wire to ground ring on the underside of the contact board, and connect a red wire to the spring. Black to negative on the batteries in series, red to positive? Is it that simple?
Simpler than that, touch a wire from the positive (red) of the battery to the spring, touch the negative (black) from the battery to the ground ring. Bingo!
If you have the leads from the driver soldered to the emitter it will fire right up. Well, as long as there’s nothing wrong. You’re bypassing the aluminum host as ground, so you can just touch the lead from the battery directly to the driver. Nice to have the star on a sink, heavy piece of metal , almost anything really, but not necessary if you don’t run it more than a few seconds at a time.
Theoretically. I’d put in a switch in there as well for convenience. Alligator clips help too, at least for attaching the leads to the spring. I’ve found that soldering the neg wire to the driver directly is the least-stressful way of doing things.
I used AA to glue a spare XM-L onto a heatsink then soldered on a couple of wires with alligator clips attached.
I bench test all my drivers prior to starting any work, nothing worse than getting a light together and finding it doesn’t work. Much easier to confirm each step along the way. I usually start by setting/confirming my modes and confirming proper output (amperage). I recheck output after each 7135 I add, if the driver no longer works or the amperage doesn’t increase by around 300ma I know where I screwed up.
In the photo below the wires from the driver to LED should be obvious, the green wire is clipped to the ground on the outside of the driver and connected to + of my Fluke. The black Fluke lead will be held against the ground of the battery then battery + touched to the driver spring. The meter can be placed anywhere in series with the battery, I have it on the ground side here but it could just as easily have been placed on the positive side. Or be left out altogether as DBC stated.
The one thing I’ve found to watch out for is the alligator clip on the driver ground or the ones on the helping hands can short the driver out if not carefully placed.
This is an old picture, I place the meter on the LED side these days to get a true indication of what the driver is providing to the LED.
itinifni, would it be more representative of true LED power if the DMM was between the negative from the LED and the black negative wire from the driver? Would this give actual emitter amperage use?
Then the battery itself would hook up directly to the spring side of the driver, + to spring and - to ground ring.
Yes, that’s exactly how I do it these days. I believe that takes driver inefficiencies into account. I’m sure I add a fair amount of resistance with all the alligator clips and wire but it’s close enough for me.
Again, this is an old picture measuring on the battery side.
It depends how you like to work. I find crocodile clips are a pain to keep in place on a small PCB when testing. I find it’s easier to tack on some wires and remove the solder later with braid. Battery holders with springs help if you don’t have a bench PSU.
What about a heatsink or housing for the driver as well, or would that be overkill? I remember someone here tested a linear driver and its output dropped rapidly after a few seconds, as the 7135s started to heat up.
Seems like it’d be just as easy to mount everything in the pill then test it. At least then when everything checked out you’d be ready to assemble the light.
I only do a short test to confirm my soldering, no extended run time. I’ve held the driver in my hands while testing and never felt any heat from the 7135s.
yeah, R'bduck's one is nice and has the right old school DIY feel to it :-) (btw haven't seen him on the forum for a while...)
Personally I do not use a dedicated battery holder, I usually use my Maratac AA copper (twisty) with the head screwed off and a Nitecore 14500 and just push it against the contact plate to test a driver.
That could be nice if you get a few pills for different size drivers, all with driver retainer rings, and then solder a neg wire to each pill. Could be good if you want to use fewer clips.
