Sofirn SF14 should come with a warning

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.


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 :wink:

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:

If someone makes a light and recommends AAs and 14500s and fails to say — but don’t use Eneloops because the light will malfunction and who knows what will happen — then that is a problem.

Hum, they don’t have to specify Eneloops, as those are only one type of Ni-MH branded cells among N others.

Just to give another example: I never used my SF14 with AA cells because the first batch of that light couldn’t even take a Ni-MH cell, only alkalines and 14500s!
I wrote this here by that time, and asked Sofirn to correct the tube so that it could take Ni-MH cells:

They could, however, specify that using Ni-MH may imply some issues.

If you check the Jaxman E3 thread, an AA flashlight, you’ll see that jaxman mentions that the use of 14500 cells is not the most appropriated as the driver is mostly done to use with AA alkaline or Ni-MH cells. In this case is due to the heat produced and the outputs being similar between Ni-MH and 14500s.

Please don’t get me wrong as I am not trying to prove a point here, nor to defend Sofirn as I have nothing to do with them. I’m only trying to check that just because it doesn’t say it (Ni-MH cells) can’t be used, it also doesn’t say it (Ni-MH cells) can be used.

However, if those issues persist, I guess you can contact Sofirn, through the forum member or through their AliExpress store so that they can help you solving this. If it has a solution, of course!! :beer:

Technical Parameters

1, Use CREE XP-G2 LED with a lifespan of 100,000 hours.
2, CCT Range: 5350K-5700K, NW (Neutral White)

  • 3, AA battery Working Voltage: 0.9-1.6 Volts

4, 14500 battery (without protect board)Working Voltage: 2.8-4.2 Volts
5, Battery Supported: 1pcs 14500 Battery or AA battery (NiMh, Alkaline)
6, Dimension: 96.1mm(length)× 18.9mm(diameter) × 20.5mm(head)
7, Net Weight: 38.7 gram (no batteries included)
8, ………

Well, #3 above kinda tells the story to me. Eneloops NiMH batteries should work.

Well, first time I’m seeing this info and their site :person_facepalming:
Doesn’t take back my point reporting to the time I got the lighr and the info, but it changes the things concerning the use of Ni-MH, not specifically Eneloops.

As I mentioned above, maybe contacting Sofirn is the best way to act :+1:

NiMH has the lowest voltage of the major types, and that’s no-load. The controller might have a hard time starting up if it’s already at a low voltage, then tries dumping lots of current to make its supply voltage even lower. At least an alkie can still register at 1.5V-ish at no load.

At lower loads, maybe the voltage holds up more. Then as things heat up and LED current decreases and/or resistance somewhere increases, the sag isn’t that bad and it steadies out.

I remember a digital watch (old-timey red LED digits) would go mental when the battery would start getting low, but noticed it was especially when more segments were lit. Ie, it might work fine at 1:17 but go mental at 12:53.

So… no idea. :smiley:

Yep your right, I should have said NiMH… not just Eneloops. :+1: I edited & made the change. :wink:

Thanks for pointing that out. :slight_smile:

I noticed that mate :wink: Thanks!!

I don’t have Eneloops nor the correspondent IKEA batteries, I only have some Panasonic Evolta Ni-MH and other “Lidl supermarket” Ni-MH batteries. I do know that Eneloops perform better, but if they are not performing well on the SF14 and other Ni-MH also don’t do the job well done, the focus here must not be the Eneloops, but the Ni-MH rechargeable batteries.

And it must be addressed to the manufacturer.

I do remember that the runtimes pointed out for the SF14 and SP10A/B was only for 14500s and AAs, and for Ni-MH they should be different but they were never mentioned. So, maybe something is missing here.

I never noticed any flickering on my SF14 or SP10A/B when running with Eneloop AA but I haven’t used them since my initial play with them because I use either my Zebralight SC5W II or Reylights when I use AA lights. The Sofirn AA lights are just not bright enough.

I have three of the Jaxman E3 with a fourth on the way.

I decided to try the Sofirn SF14 because of 1) the price 2) it is slightly thinner than the Jaxman, although longer 3) and because of Jaxman’s warning about using 14500s.

The AA size lights make for good pocket EDCing. They also make good gifts. That’s why I need them to use both 14500s and Eneloops. Most non-flashaholics won’t use lithium ions. So I include Eneloops with the flashlight, along with a charger.

The Jaxman E3 produces enough light on Eneloops for me to take the dogs out in the yard to pee. But not enough light to walk them in the park. That’s why I like a light that uses both Eneloops and 14500s.

Someone mentioned contacting the maker……that is where I started…. But the only option Amazon gave me was a return.

Since Sofirn sent me a model I would consider defective AFTER they introduced their new version, I would be suspicious of what they might send me next if I bought a second SF14.

My suggestion to Sofirn — take all the version I SF14s off the market and remove the link from Amazon and elsewhere. Start a new link and label it Version II or new and improved or both.

And then specify whether or not it works with Eneloops.

Thanks for posting. 4A is going to bring significant voltage sag, and with an NiMH, there isn’t a lot of voltage to start with.