Q8, PMS SEND TO THOSE WITH ISSUES BLF soda can light

Returning shipping to China usually starts at $60 plus there may be additional customs fees, so that is not really an option. Warranty related stuff would be them sending you a replacement head or whatever part is bad. It’s cheaper for them for you to keep the bad item.

If I had to guess, I’d say the FET is not working. Channel one uses a 7135 chip that allows .350mA to go through (about 150 to 200 lumen) and as you ramp up it switches to channel two which has the FET that provides all the higher currents.

I don’t know what could cause it turning on and off on it’s own, though.

Are you able to make a video of how it’s acting?

Are you sure it’s a Q8? Those don’t have built in charging.

As you suspected, it’s not a Q8. It is a SP36. If I’m in the wrong spot, let me know. The directions specifically cited this thread to get support.

I’m trying to upload a video. What that video displays is me screwing in the batteries and receiving 2 blinks. I feel like your hypothesis is directionaly correct. Instead of moving on to a higher power it simply shuts off.

I sent Sofirn US an email so hopefully they have some input.

Note: It’s hard to get a video of it turning on and off. That said I just saw it light up across the basement unprompted ha.

The SP36 driver is basically the same design as the Q8, but with a charging circuit designed in. It’s still a single 7135 chip and FET design. So what I said before still applies. If the FET is not working then you only get from moonlight to about 200 lumen. Some early versions of this light used NarsilM and later versions used Anduril. Unless I’m mistaken, both user interfaces use the same basic method of transitioning between channels one (7135 chip) and two (FET). As you ramp up once the 7135 chip reaches full output it stays there and the FET starts to add power.

So a bad FET would make it ramp up the 200 lumen and then just stay there. A double click to Turbo would shut off the light as that is the only brightness level that uses the FET only.

It definitely sounds like you have a driver problem, unfortunately the SP36 driver is glued in and not easily replaceable.

I would contact the store you bought it from to see about getting a replacement head or whole light.

I imagine you folks know this but I traded emails with Sofirn and they couldn’t have been more responsive and helpful. I provided a video and we tried some basic trouble shooting. In the end, they are sending out a replacement. Thanks again for all of the help here.

Sounds good.

Good going, Sofirn.^

So I finally managed to check the connections and everything seems to be nicely attached. I didn’t see any scorch marks or anything obviously amuck.

I decided to pick up another light to test and it won’t light either. I’m guessing that there’s a problem with the batteries or that I have two dud lights, which seems pretty unlikely.

I checked all four batteries on a meter and they all read around 357 or slightly higher.

Any better way to test the batteries without another light?

Any other ideas?

I’m thinking of picking up a new set of batteries but am trying not to spend a fortune just trying to get it working.

Hopefully I can get up to speed and learn a few things along the way.

Thanks everyone!

Do you mean 3.57 volts? That should be sufficient to light up, but not on the highest outputs.

Have you access to any other known to be working light that you can try a cell in?

Sadly, it’s the first (and only) 18650 light that I own.

I’m not even a novice with electrical. Computers, printers and gadgets, heck yeah but once it gets to the nuts and volts, I’m pretty clueless.
I was measuring DC and I think I had it set to 2000m.

What kind of battery charger do you have?

Are you inserting them with the correct polarity? Button tops against the big brass ring?

If you have a digital multimeter set it to DC voltage. If you have to choose a voltage range, use 10v to 20v. Verify it’s working by measuring some AA or 9v battery. Something you know is not dead. Fully charged they should be 4.20 volts or close. The lowest they should ever get is 2.5v. The Q8 flashlight gives a warning at 3.0v and will turn off power at 2.8v.

Any videos or pictures might help us. Your issue seems very strange so it might be something simple that’s being overlooked.

I think we are on different wavelengths here…. not sure you have the multimeter set for DC volts…. I have no idea what the “2000m” you mention is. Can you post a picture of the meter set the way you are using it?

2000mV FS, and if so, that means 0.357V, which is kinda scary.

No wonder it doesn’t turn on.

Move your meter to the ‘20’ setting for DC voltage and try again.

Here’s a quick guide to using a non ‘auto-ranging’ meter like yours.

I guess I’ve been badly spoiled by my autoranging meters. :person_facepalming:

Good morning!

I’m attaching some photos to help clarify.

Here’s a shot of the batteries positioning in the tube.

Here’s a shot of the driver/contacts.

And a shot of a battery on the (cheap) meter.

Also. I dont have a picture of it but I’m using a nitecore four slot charger.

pics are too small, I can not read the setting on the multimeter, but i guess that you are at 0.355 V

The funny thing is that I have a nice autoranging meter and just can’t find where I put it.
I (with the help of a good tutorial) was testing a couple electrical outlets back before Christmas.

I guess it’s good that I have a cheap backup.

I’ll change the settings and report back in a bit.

At 20 DC, I’m getting 0.35.

Sorry about that. They were supposed to link.
I’ll fix them in a bit.

0.35V basically means that your batteries are dead, too much discharged to be considered safe, even if they do charge up again.

I wonder how that could have happened inside a Q8? When the light is switched on it has a low voltage protection and will shut off with the batteries still at 2.8V. When off, the green indicator light will drain your batteries lower because of the small drain/MCU not powered, the LVP will not work (at least that is what I have understood), but that green led uses so little power that it should drain the batteries in years, not weeks.