Has anyone seen an issue of de-domed XM-L2's (or XP-G2's) increase Vf after de-doming?
I'm running out of ideas. I've been using the IOS 3.5A driver configured for 3S cells, 3S XM-L2 LED's (Shocker) and it goes into direct drive mode on high, but med and lo modes still work. In a de-domed 3 LED Shocker, tried 2 drivers and both go direct drive in high only - lost med and lo. Checked 1 of those drivers in a 3 XML domed test and all modes work fine. I carefully checked wiring, etc. and all looks good.
BTW, the IOS 3.5A driver (now 4.5A on IOS website) is identical to the LCK-LED 5A driver, except more resistors on the LCK-LED.
I've had issues with some of mine not working in moonlight mode after dedoming, but never any of the higher modes. Those are single LED lights; is your troublesome one wired 3 in series or parallel?
Ooops sorry, for 3S I meant 3 in series - it's a BTU Shocker. Hank had told me the IOS driver will go direct drive in a 3S - 3S configuration, which worked fine in all 3 modes in 3 previous Shockers of XM-L2's but with the domes. Maybe I'll re-check the emitter wiring, but funny, because I think at first it did work, so was thinking on fully charged cells it worked - that's why I'm thinking maybe the cells has enough voltage to run it properly when fresh, but this morning I tried several sets of cells, some at 4.2v and still not working in med and lo.
I had a high amp de-domed XP-G2 light I did previously have reduced amps after de-doming, so seemed like the Vf demoand went up after the de-doming, but was just one sample, so wasn't sure.
Frustrating. I tried a resistor mod to the BTU driver and never could get it to work - PilotPtk did it successfully - I even put a jumper over the resistor, and didn't effect max amps at all - tracing the circuit, there's a few components the neg. signal goes thrue before the last resistor, so I'm thinking there's something more complicated going on, not sure. Could go to the DRY driver, but that driver sucks: poor PWM's, and stupid 2 minute time out -- wish I could disable that, but also not sure if I can get as high amps out of the DRY driver. I can get over 5 amps from the IOS driver.
I would check the LEDs individually, starting at very low voltage and seeing where each one starts to work.
Series wired LEDs mess with my head. I've seen stuff too weird to explain, like one LED dead and the others still working fine, which in a series circuit doesn't make any sense. Checking the dead LEDs show they are complete open circuit both directions, and when powered individually no current will flow either direction. Yet in the circuit, the other LEDs still work.
Maybe you're right - should check the emitters out carefully. Unfortunately I don't have a bench power supply, but actually I did try a BTU driver and it all appeared to work properly, good amps, good output, but of course just not enough power . I'm a little demanding when 3.8A isn't good enough ... At over 5 amps, I measured 415 kcd in throw at 4.3 meters, so I think the # may be higher at a longer distance - a lot of potential, with a lot of heat, though the Shocker has a couple of lbs of heat sinking.
Output voltage & current independently adjustable... you can start with the voltage turned way down and current turned way up, then increase voltage slowly and see when they light up (letting the Vf limit the current).
Ordered! That was easy - looked it over, basic, but everything there. Thanx comfy!!
I got lots of parts to play with for now - I did try 2 of the IOS drivers already though, but I got a DRY driver, LCK-LED driver, plenty of spare LED's, and 2 more Shockers... Ouch. Either I got a lot of stuff to scrap or enough to figure this issue out, not sure....
Thanx ryansoh3 - not sure at this point because I've done a lot of XM-L2 de-domes in single emitter lights and don't think I saw a hit on Vf so much, so, maybe there is some issue with one emitter of the 3 I got wired.
Yes, they work fine. I have that same one I linked, and a smaller/lower current version that also has an adjustable cutoff for use as a battery charge controller, using that one to run a 12v fan on a 30-36v 100w LED array.
Just asking because I lost the lowest mode in my K40 mod (de-domed XM-L2 1A on Noctigon + 2x0.1ohm resistors). The emitter doesn't even glow in the lowest (1lm) mode and 2nd mode puts out about half of the amount stock puts out. Modes 3-6 work fine and put out more than stock.
The cause of my Shocker issues was a short - partially exposed wire at the solder joint on the PCMCB making contact with the reflector - fixed that and the modes returned. As far as de-doming causing a rise in Vf, I think that happens but still not sure - no time to further investigate myself.
With my K40, I bridged the resistors, as vinh does, and haven't noticed any loss in modes including the lowest mode. I'm using heavier gauge LED wires, lapped the star/pill top, de-domed the stock emitter, etc...
I've had several dedomed XML2s that did that, no shorts or partial shorts, swapping LEDs fixed them.
The dies are soldered onto the substrate, maybe heat from reflowing affects that solder joint but with the dome still in place it's not affected. Remove the dome and the die loses full contact with the base? Who knows.
I wonder if the new copper mcpcb's may be causing some of these issues. I have had to reflow some emitters several times to get them working properly. I didn't have these issues with aluminum bases. It just seems issues not being able to achieve high currents have become more common at the same time the copper bases became SOP.
I'm not saying I'm against copper bases. I'm just saying it seems they need more finesse when reflowing.
. I'm a little demanding when 3.8A isn't good enough ... At over 5 amps, I measured 415 kcd in throw at 4.3 meters, so I think the # may be higher at a longer distance - a lot of potential, with a lot of heat, though the Shocker has a couple of lbs of heat sinking.