Hello,
I attempted a spring bypass on the three springs in the bottom of my Sofirn Q8 Plus and it worked for a few days. Then one day I was using it on turbo and it shut off on its own. Then when I tried turning it on only two LEDs lit up. I removed the wires from the springs hoping this might fix the issue. Now when I turn up the brightness, only one LED illuminates and it turns blue when it gets too bright.
Any advice or help would be greatly appreciated.
Thank you!
I haven’t done any mods to the driver side of things, but I pulled it out to see if it looked like there were any popped or burnt components and it all looks fine to me…
@dr_gvo I know it’s a bit of a late reply and I know you aren’t on BLF that often, but I just wanted to ask: did you ever found out what failed/went wrong?
I ordered a Q8 Plus myself yesterday and was planning to do a spring bypass myself (and maybe thicker driver wires in the future), so I was reading up on the Q8 Plus and I stumbled onto this topic.
From what I’ve read (only) a spring bypass should be fine/still safe (enough) for the Q8 Plus; only when you start modding more (thicker driver wires and/or LED’s with lower Vf), you are getting close(r) to breaking point.
Any chance you still remember what batteries you used when it failed?
I’ve heard people burning out leds with molicels
Was that with or without spring bypasses? (I assume with?)
I was doubting if I would use Samsung 40T’s or P42A’s in my (yet to recieve) Q8 Plus, but since the store I buy them from (Nkon) states that the P42A will be in stock again “somewhere in April”, I will go for 40T’s for now. (Even though that is also a slight question mark, since Nkon has them listed as the new(?) 40T5.)
It’s really weird in terms of the inconsistency from what I’ve read about failures in the Q8 Plus; some people do a (quite) a bit of modding and seem to easily get away with it, while others do a minor mod and have problems. Almost seems like there is quite a variance in within the different(?) batches of the Q8 Plus.
Not sure now if I will do a spring bypass; maybe as a compromise I might do a 20AWG bypass instead of going to 18AWG immediately. Unfortunately I don’t have a lumen tube/sphere, to get an accurate indication of how it performs out of the box.
Would also like to open it and check the application of thermal grease/compound (and maybe apply some MX-4 in hopes that it might be a slight improvement), but with the complexity of all the wires that have to be desoldered, it is something that I’m a bit hestitant to do.
I think I damaged a FET in my first Sofirn Q8 Plus by using 3x LR2170LH cells:
The springs came bypassed. It reached about 28.9k lumens at turn on.
I did a review of a second Sofirn Q8 Plus where the springs were not bypassed at the factory:
The first Sofirn Q8 Plus is sitting on my workbench to be repaired (replace a FET and 7135).
Here’s my review and a bit of a teardown:
I read your review indeed and several of your posts here in the forum, regarding the Q8 Plus and knew that you had (almost) managed 29K lumen before it broke down. You didn’t do thicker driver wires, right?!?
I also read through @DB_Custom his thread (Sofirn Q8 Plus) and all the mods that he did, and I knew he had swapped the driver wires to 18AWG (from 20AWG I believe), but by reading it back now, I noticed that he also swapped out the original (‘cheap’) FET’s for quality ones at the same time.
With the 40T’s he used, even after all his mods, his example seems to have survived.
I assume that Sofirn stopped putting spring bypasses on them (out of the factory), because they were aware that it was pushing the Q8 Plus close(r) to its limits.
As far as I can remember, all the Astrolux EC06 came with spring bypasses (and also hit 20K+) and, I might be wrong though, but didn’t see (as) much stories of those failing. Wondering if some things/parts have changed (for different/cheaper parts) and that the Q8 Plus is a bit more ‘fragile’?
On a sidenote: I just ordered 40T’s for it (which might be the ‘new’ 40T5?!?) given that the P42A and P45B weren’t in stock and also because the P42A (initially) maybe pushes a bit too hard, let alone the P45B. With 40T’s I still get a good high drain cell, but maybe a bit less ‘extreme’ than with before mentioned Molicels. (Although the P42A has a bit more voltage sag initially, than the 40T if I remember correctly…)
I didn’t change the wires.
Perhaps the quality of the FETs could be improved.
I believe that Dale/@DB_Custom did that on his Q8 Plus, but that still leaves the option/risk open of pushing the XHP50.2’s past their limit and damaging them, I would imagine.
XHP50.2 are extremely robust. Like XHP70.2, they can even withstand too much current for short time (they will turn blue), with no consequent damage.
The MOSFET is more likely to burn out than the LEDs.
They’re robust if soldered correctly, I’ve fried some 50.2 as a result of high thermal resistance before.
But my Q8 plus with bypassed springs and LR2170LH was fine on turbo (host got to around 80° with a calibrated 60° thermal limit)
You can purchase the driver separately from Sofirn:
Sofirn Flashlight Driver Circuit Board Chip for SC18 Q8Plus LT1S SP40A C8G SC31 Pro IF25A SP33V3.0
Yeah, if checking the datasheet they aren’t really good for that kind of voltages and currents. Resistance shoots up wildly under 4V causing increasingly more heat.
Yeah, I noticed that too a few days ago. Not cheap (partially due to shipping cost), but good to know that it’s at least available. Makes that I feel a little bit better about trying to push the Q8 Plus a little bit harder. (By at least installing spring bypasses.)
Yeah, DB_Custom/Dale also mentioned in his topic that the original FET’s are mediocre quality and swapped them out for better ones. I don’t have the knowledge to determine which suitable FET’s are better quality, but maybe I will try to find the same infinion FET’s that he used. (I can read the ‘product number’ on one of his photos.)
Not sure though if I want to go through all the trouble/work of swapping them beforehand for “just in case…”.
SIR178DP is probably a good option.
Thanks, I will look it up! 
I did look the SIR178DP up and unfortunately Mouser did not have it in stock (expected to be in stock in 6 months time).
Digikey does have them in stock, but shipping costs are € 18,-, which is roughly 3 times the cost of 4 of those FET’s (3 + 1 spare).
I also could find them at a Belgium company, but they almost charge the same in shipping cost as Digikey.
I also looked up the FET that DB_Custom used, the BSC009NE2LS5, but Mouser (and Digikey) don’t carry it (anymore). I did find it at several stores on Aliexpress that sell them, from around € 10,- (shipped) for 5 pieces, but with a lot of those listings I’m doubtful if it are originals and with a component that is going to be pushed quite hard, I don’t want to have a ‘doubtful’ knockoff in my Q8 Plus…
I will initially keep the original FET’s in my Q8 and maybe only replace them if they might break. (Although with these shipping costs at Digikey and that Belgian company, it’s cheaper to just order a completely new driver directly from Sofirn!)
