Ok friends, I am at a total loss of words. I need a logical explanation for why my flashlights are slowly dying. Now I have 5 flashlights that are “duds”, meaning they turn on, but is permanently stuck on a firefly-type mode when the flashlight doesn’t even have a firefly mode in its settings. They are my Convoy S2+, M2, Roche LS01, Trustfire 500a, and some Lixada triple. They all use XM-L2s except the Trustfire, which has some Philips LED in it. They all use 18650s. They all died in similar fashion: turned it on for a few seconds on high and then it went out completely. Tried turning it back on and the LED is on a firefly brightness. Can someone please tell me what’s going on? Is that what I’m to expect with these flashlights?
The Roche, Trustfire, and Lixada all happened a while ago described in this post. . While the S2+ happened a few months ago and the M2 just this morning when trying to fix something under my kitchen sink.
I’m seriously bummed ya’ll……
edit: the Convoys’ modes are still intact. If I look closely there’s a small difference in light when I toggle through H-M-L. And when on the lowest firefly, it will still do the blink after 5 seconds to change mode groups. So the driver still seems to be working.
Have you tried plain ol’ swapping? Eg, try a cell from a “dead” light in a known-good one?
Also, helps to be systematic. Eg, crowbar the (-) end of the cell right to the case, bypassing any switch.
Then check the cell as above.
That (almost) leaves just the driver and LED. LED obviously lights, albeit dimly. That leaves the driver. Hard to test it in situ, so to really test it means desoldering it and removing it from the light.
The “almost” part is that there might be a high-resistance connection somewhere, between threads (tube and head, body and pill if any, driver and retaining-ring, etc.). Or maybe a wire got flexed enough to slowly break strands one by one ’til just one skinny one was left, high enough in resistance to not act like a fuse.
Man! That many lights. Does seem odd? Are you for sure using quality cells? Seems like a dumb question but it’s the only symptom that can be transferred from light to light. Is your charger confirmed to be charging well?
Hmm, with the add’l edit, it sounds odder than before.
Sounds like something’s “blocking” the current from getting to the LED. Given variations in intensity, high is still brighter than low, etc., that sounds like a too-high resistance.
Doubt all the 7135s would go pouf at once. Their all connected in common. Even 1 running full tilt, and 7 blown, would still be pretty bright. Kinda sounds like a bad ground, then. Cracked solder joint? Cold solder joint? Loose retaining ring? Something along those lines…
Thanks so much for the responses everyone. The only 18650 cells I use are Samsung ICR 26F M, SDIEM, TDY4. I’ve wiped down all contact points, swapped cells, tightened rings… I only have one more working 18650 light now, my trusty BLF A6. I DON’T want to fry this one. :cry:
To have that many lights fail surely means that your cells, or something you are doing is causing the issues? Or you’re a wizard, in which case anything electronic will fail.
What voltage are the cells at when you insert them and are they at the same voltage when you remove them after testing the dead lights?
What happens if you use a DMM to check the amperage on the dead lights?
The cells are all sitting around 3.9. The strange thing is that I just use them intermittently. Like the M2 I was using just the other day to look for a bug, and then this morning, POOF. I get little to no reading when I bypass the tailcap and measure using my DMM.
Actually, don’t laff. I know people who are “cursed” in a sense. Watches (mechanical and electronic) seem to die within a year. Flashlight bulbs go pouf within weeks. Keyfobs stop fobbing. They just seem to have some “aura” which zaps things they come in frequent contact with.
l had similar symptoms and problems with some of my lights before and guess what, l over-greased the tailcap, grease creeping to the unanodized portion of the tube, breaking or making intermittent contact.
i had a lot of little cheap lights i started modding on? and i finally ran into one where i had to solder the driver with a blob of solder bridge to the pill. till i figured that out, the light was erratic.
of course a blown driver once gave me a “firefly” led… swapping a driver into it cured it.
Could there be excess lube on the threads between the head and the tubes that sneaked into the driver, or coated the mating surface between the tube and the head?
What kind of of lube was used?
Are these all modded lights? Factory lights? Some of each?
If they’re modded, was acid core solder used?
Could the area they’re stored in have encouraged corrosion? Do you live near salt water?
So many possibilities, but those are too many failures to be coincidence - it’s quite likely they share a common cause.
Try charging your cell’s in an analysing charger. If your charger malfunctions, you think your batteries are topped-up.
But if they are already over-discharged, they might have lost all of their capacity.
I have had some cells that I could charge in a jiffy, but gave away in seconds once I put them in a flashlight.
When you start your car in the morning and you don’t see a little red light that keeps on burning, that can mean 2 things:
a/ your engine is OK or b/ the little red light is kaputt.
^ That was my thought about before and after voltage, but I hadn’t thought about bounce back, only probl is that not everyone has an analyzing charger.
That’s why the CEL/MIL lights up when you turn your car on and goes off when you start it, so you know that the light still works.
I wasn’t joking. My wife is one of those people you mention, she is pretty computer savvy - knows a bit of coding etc. but the frequency with which she suffers computer problems is rather amazing. Usually the solution is as simple as her leaving the room and I will do a restart.
Are your leds on DTP boards? (Noctigons or Sinkpads). Overheated leds (i.e. not completely burned bondwires) tend to not die completely but leave a firefly amount of light.
The Roche was modded so when it went out, i figured the mod finally went bad (ie: solder making contact with something else). But everything is stock. I rather liked how the S2+ and M2 were driven so I never touched the internals. The cells can’t be bad because they work on the A6. I don’t have an analyzer but I figure if they drive the A6 just fine, then they should be enough to drive 2800ma Convoys.
I took apart the M2 and saw that the star had come off the shelf. I guess the thermal compound wasnt enough to keep it glued down. Possible that the LED just overheated without proper thermal path to the body. 1/2 a mystery solved. 4 more to go?
