Also.
I’ve been in correspondence with Sofirn through their Aliexpress store. They have been helpful in discussing a way to remedy the issue.
They have also added a listing specifically for the SF14V2 (mine is the V1 apparently). Physically it looks the same. The differences that I can spot are that V2 is printed next to the logo and the anodization seems to have a glossier sheen.
Mine arrived just Wednesday…. the flickering doesn’t stop — it is not usable on high.
I do NOT see a V2 anywhere…… disappointing that Sofirn would send out an older version AFTER they have produced a new one to deal with this serious defect.
Yeah, they should list the old version as supporting 14500 only, or stop selling it altogether.
I had the same issue, received a replacement light but it does the same
turbo flickers a lot at start, however, it only happens when the cell is fully charged, and if you wait 10 seconds it stops doint it
Anthon, any idea which version your replacement was?
I wonder whether using an Eneloop Pro would help. I think the Pros can source more current than regular Eneloops.
In two SF14 I had the same problem, it’s funny…
Eneloop pro doesn’t solve the problem
First version, it was many moths ago
A moth in front of your light could certainly cause some flicker. :smiling_imp:
Yep. Maybe it thinks there is an alkaline in there. LOBAT trip at 1.2V would be appropriate for an alkaline cell. I have this light and I have also tried it with an eneloop, and the same thing happened with me. I refuse to use an alkaline battery again. Alkaline cells are the most expensive way to have portable power. I stuck an 14500 in it, and it works just fine.
You can’t really blame the manufacturer. The light works well with a duracell AA, which is that battery that they intend to be used. Not everyone will put an eneloop in there. Even fewer people would put a 14500 Li-ion in it.
Cheers
Sorry, that’s just wrong.
Unfortunately, it’s probably correct. The vast majority of people have never used rechargeable batteries of any kind in their flashlights.
I’m not sure what the demographics of Sofirn buyers are, but they’re probably not all flashaholics.
That said, there’s no excuse for not designing devices to accept NiMH batteries. For at least half the capacity, a NiMH cell will be running with a voltage higher than an alkaline. If a device won’t work with NiMH, then it will be giving up half the capacity of an alkaline too. Running your devices only with full alkalines is even more expensive.
Nope, not really, though they can source it for longer:
I just checked my SF14, purchased a few months back. Before I put in a battery, I checked the retaining ring for the switch PCB to see if it was loose and needed to tighten it to be sure of good contact. Then I put in a (not recently) charged 2400mAh Amazon Basics LSD NiMh and switched it on. No problems. Nice steady output.
I left it running, pointed up on my desk. After ~5 minutes, I noticed it was flickering sporadically. Switched off and on again, more sporadic flickering.
Now I’ve gone and tightened the driver retaining ring too. After a a minute, a bout of flickering.
I have a few ideas. I have a Utorch UT01 that I power with the same type of cell. From specs and observations, they both seem to have similar levels of output. I’ve noticed that the UT01 won’t reach its highest mode and/or will flicker sometimes. Tightening the tailcap solves the problem. So, one thought is that part of the problem is resistance and resulting voltage drop at relatively high currents. I note that the UT01 has double tailsprings springs, while the SF14 only has a single tailspring.
This doesn’t necessarily explain why the flickering seems to come and go though, unless the v1 lights also have active thermal regulation, beyond just stepping down on a timer, and end up reducing their current draw to manage temperature.
Some added evidence that supports the hypothesis that thermal throttling may be responsible for the flickering ending once it starts.
Shortly after switching on and going up to turbo/high, my IR thermometer reads a temp of ~70°c from the emitter. The temp drops somewhat once the flickering starts, which isn’t surprising. However, when the flickering abates a minute or so later, the emitter temp stablizes at ~65°c. This is not a result of the driver dropping down a full level, it’s still in turbo/high. If I do a quick press, the light wraps around to low mode.
I may try doubling up the tail spring later tonight.
This kind of issue with eneloops has been reported some months ago. Ex: DOUBLE 1 AND ½ "REVIEW": Sofirn SP10A and Sofirn SF14 *[added night / distance shots] - #12 by AgentSteel
Also, and this is a mere indication, the user manual (at least the one I have) comes with indications for 14500 batteries and AA alkalines (sometimes it is mentioned “AA battery - 1.2V or 1.5V (nominal voltage)” ). Ni-MH are not explicitly mentioned in the user manual specs.
This is what it is and doesn’t necessarily interfere with the discussion above!
Exactly — the maker/seller specifically mentions 14500s.
No indication that Eneloops should not be used.
Maybe lack of thermal paste?
Well, the same goes for they don’t indicate that the use of Ni-MH cells is “recommended” or considered 
An example: Lumintop Tool AA explicitly mentions the use of 14500 Li-Ion, AA Alkalines and Ni-MH cells. Nitefox ES10K (AA) mentions AA Alkaline or Ni-MH cells. Manker E11 mentions 5 different types of batteries that can be used.
The Sofirn SF14 and SP10A/B only mention 14500 batteries and AA alkalines!!
EDIT: As I mentioned above, the only reference that may lead to an inference about the Ni-MH cells is the “nominal voltage” of 1.2V!
Here is a video with mentioned issue with current measurement:
