The charge matching is one of the big reasons I like the SP36. Having a built-in charger allows me to charge all the cells at once, to exactly the same level… even if that level isn’t 4.20V. Otherwise it’s kind of hard to do a partial charge on a married set of cells.
But if you’re charging until full, there should be no problem charging two cells then charging the other two.
Hi, I’m having an issue with my BLF Q8 and I’m trying to find out if there’s anything I can do to fix it or if I have to return it. I’m not technical with torches, but I’ve been reading posts, manuals and guides to try to figure this out.
When ramping up, it stops at a fairly lowly level. If I continue to hold the button, it still double flashes after the amount of time it would normally take to reach full brightness. When ramping back down from “full” brightness, there is a delay until it reaches its limited brightness level and then decreases to moonlight as normal. If I stop ramping while it is below its limit, the button flashes only once. If I stop ramping while it is above its limit, it flashes twice. This makes me think the FET channel is not working.
I’ve tried doing a factory reset from the version check mode. It does the rapid flash to confirm reset has occurred but it continues with the same behaviour.
It was working fine yesterday. This issue started after doing the latest recharge of the batteries. I’ve used it on and off over the last 6 months since I bought it with no issues. I bought the batteries brand new at the same time (Samsung 30Q 18650 button tops).
The only other weird issue I’ve found is the battery indicator seems to be reading low. The freshly charged batteries each read 4.2V in my charger (XTAR VC4), but in the torch it indicates only 3.1V.
Any suggestions on what’s wrong and what I could do to fix it? Or should I just return it to where I bought it? Or should I be asking elsewhere?
It does sound like the FET has stopped working and your only running on the single 7135, so maybe 150 lumen max. A video to show what your describing would help, but I think I understand you.
You can try a return or warranty replacement, but I don’t know if they will do anything since it worked fine for 6 months.
With a bad FET, you can buy a new FET for a few dollars, but you need hot air to swap it.
You can also buy a complete new driver here for about $10 usd. You will need a soldering iron for the led wires.
I’m curious if others also think it’s the FET. The battery thing is strange. With fully charged cells it might read 4.1v, but 3.1 is strange.
dunno about the battery voltage readout, but the ramping behaviour sounds efinately like the FET not working, or the trace from MCU to FET not making contact. First try could be soldering some extra solder to the legs of the FET and perhaps the leg of the MCU that goes to the FET-gate. That tests a possible bad solder joint that originated over time.
Also check the battery control contact with the brass ring. I had a set of batteries that I used and only one worked. I rearranged the batteries and tightened fully they all were in contact, it worked fine.
I wouldn’t bother messing with the FET or getting a new one. The incorrect voltage readout indicates there’s more to the problem than just a bad FET. Get a whole new driver, or new light.