I’ve been using these in builds for years now, but I’ve ordered 2 batches in the last year or so and they have all nearly instantly failed when high current is drawn through them.
I get them with Bistro and pre-soldered wires, I picked up 3 back in November. 1st one went into a C8+ with a” Epistar “XHP 110” 4x4 3v array”:https://i.redd.it/d48s480wd9061.jpg , and I immediately encountered an issue where the 3-4 lowest modes were all the same brightness after testing the build with a 30Q. I messaged Richard after some troubleshooting, and we came to the conclusion that the 7135 had probably failed. I was offered a replacement 7135, but I lack equipment to do smd soldering and turned it down, thinking it was a one-off anyways.
The second went into a S2+ with a Boost HX, and I limited that one to a 18650GA since a 30Q and FET will toast the LED. This driver seemed to perform normally for the time being, but more on it later.
The third I eventually swapped into the same C8+ above, taking care to not short anything out. It functioned normally at first, but as soon as I ran a few turbo cycles with a 30Q (to the point of being hot in the hand, and never more than that. Maybe 15-30s maximum.) the lowest modes immediately stopped working afterwards, even through factory resets. Symptoms were identical to the first one.
It was around this time I heard about a bad batch of 7135’s going around, IIRC FF-Light had published a notice about some lights that had gone out with bad chips, and I simply assumed that this was related.
Fast forward a few months, and I was working on a new project; an SBT-90 S2+ (don’t ask). Needing a driver, I took the one out of the Boost HX build from above, that had been working fine on a Sanyo GA for months. Once assembled and tested with a VT-6, the same issue shows up.
Late June this year, I ordered a new batch of 4 more drivers with the same config, assuming that any issue with chips would have been sorted by now. 1 went into a S2+ with an SFT-40, running an 18650GA to limit amps. That one has worked so far. A second one went into the aforementioned SBT-90 S2+, and after the third long-ish turbo cycle (again, 15-30 seconds) the low modes no longer work properly, just like the drivers from the year prior.
Am I asking too much of these drivers? I’ve used them in triple XP-L HI builds, as well as XHP-50.2 with 30Qs and spring bypasses before with no issue in years prior. I’m not damaging them during the soldering process either, as I order them with wires and springs pre-soldered to avoid that exact scenario. Is there another source for quality FET drivers with Bistro that can be had in Canada? I’ve ordered TA drivers built by a BLF member before, but those ended up being reflowed poorly and not functioning properly, as well as being a short risk.