Sofirn Q8 group buy (gb closed, but try PM to Sofirn for discount)

Odd because my BFL versions (3) are all on spec with a warning at no more then 3v and shutdown at 2.8v. all 3…. perfectly.

I think NarsilM v1.0 is 3v warning and 2.8v shut down. If it shuts down a bit sooner I don’t think I would call it an “issue”. The batteries are still virtually dead. I usually recharge at 3.6v or 3.7v.

Do you typically run the batteries down real low?

I have not checked mine yet, but anything in the 3.2 V - 3.1 V range is OK with me. The batteries are about shot then anyway. Lower would not bother me either… the 3.0 V - 2.8 V would be fine too.
In most instances I am going to recharge them before they hit LVP anyway.

I don't know what q35s batteries are but here's the discharge curve of 30Q batteries (taken from HKJ's test):

At 3.22V resting voltage (=comparable to 0.2A discharge), there is 11% energy leftover in the battery (if you take HKJ's safe 2.8V as empty) , at shutdown 8%. The Q8 draws about 4-5A per battery, so at that discharge state the voltage under load is about 0.12V lower than the resting voltage, so 3.1 V in your Q8 at LVP-stepdown, which is a littlebit too high but nothing alarming, not much left in the battery anyway.

cant believe I missed this one

Riddle me this. My BLF Q8 tube works on both heads but my Sofirn tube only works on the Sofirn head.

My Q8 has been modded. Screws, bypass, Anduril, LEDs.

Any ideas what would cause this?

Tried two diff button tops. Indicator LED does not turn on.

DB Custom, Thank you for the video! That tint isn't too far off from the XP-L HI, at least as far as I can tell.

Possibly the o-ring. It might be preventing the tube from screwing all the way in so it touches the driver.

Or the throw of the threaded end is shorter, not allowing the ground contact to be made. Sometimes lights are like that, many lights you can’t flip the battery tube around for example.

the O ring on the Sofirn is in a slightly different place and it looks like in order to make that tube fit they removed a thread from the inside of the Sofirn head. You can see an entire extra row of threads in the BLF Q8 head

I need two more 35Es for the full set, but I had some things laying around to put an 'adapter' together. Precautionary measures like placing electrical/kapton tape over driver screws must be done but this could help in the scenario above or for using flat top batteries:

flat top adapter link to album removed.

The 26mm OD copper washer stays in place as the friction against the batteries is greater than against the driver ring. The O ring, I thought, might inhibit contact but it didn't and the light works. I also had an idea to insert slim dowels, tubes, etc. to hold it centered in place. Another caution, the light is assembled on a flat surface, slowly, to make sure everything stays in place.

In the picture it looks like the bottom battery has damage to the wrapper. In that case nevermind the tape and screws it will just short to itself. Solder blob seems much easier

Also, in my example the batteries are making contact its the tube that isn’t. Ill just keep the original tubes with their own light but it does make you wonder what else they changed.

You're right about that. Good eye. These are some pack pulls and I used them for staging the photo. In practice, I would use some brand new batteries that are spread across a few lights at the moment.

This looks like an incredibly bad idea. It would be much safer to simply buy button top batteries or to solder blob existing flat top batteries.

Jason, I have to agree with you. Edit: Images removed for viewing via link.

Thank you for the photo link. It seems I'm not able to make the linking work (??).

This does show some ingenuity, but I have to agree with Jason…… “This looks like an incredibly bad idea.”

A very high chance it’s not a matter of “if” things go bad, only “when” they go bad.

Thank you!

/\ . . :+1: … :slight_smile:

Yeah, bad idea. When that copper top piece shifts due to a very hard knock/fall, the batteries might go kaboom. Though i have seen the datasheet, the 30Qs ought not to vent even with a dead short.