I purchased the Sofirn SC31b myself from Amazon UK (affiliate link). It’s also available from Amazon US. This is an impartial review.
Sofirn have produced a great budget light in the SC31b. The simple user interface, USB charging, included cell and pocket clip make this a great flashlight for all and easy to recommend to others. The light is low cost but Sofirn haven’t cut corners with this light.
The SC31b is an updated version of the SC31. The main differences are the slightly different head shape and an increase in lumens from 600 to 1000lm.
Sofirn SC31b specs
Sofirn list the SC31b as:
- 1000 lumens
- 207 meters throw (10.7kcd)
- 5 light modes (Eco = 10lm, low=150lm, mid=400lm, high-1000lm, hidden strobe)
- 117.5 mm (length) x 25.4mm (head diameter)
- Made of 6061 Aluminum Alloy, Toughened mineral glass lens
I measured the SC31b as 107g with the included cell and 61g without
What’s in the box, manual, accessories
The Sofirn SC31b flashlight from Amazon comes as a complete kit. Included in the box is a 2200mAh 18650 cell, micro USB Cable, 2 spare o-rings and a manual. The store description said it included a lanyard but mine didn’t have one.
Cell and charging
The cell that comes with the SC31b is only rated 2200mAh. High end cells are 3400mAh, so runtimes could be 50% higher if you switched it.
The SC31b includes a micro USB port and charging cable. The cable has been added to my collection of over 100 micro USB cables. The charging port has a rubber covering, which looks like it’ll keep water out well enough.
The light works on eco mode (10lm) when powered from USB, without a cell or even the body tube. That means it could be used as a nightlight.
When charging, the blue button indicator light flashes, then turns solid blue when fully charged.
Appearance and quality
The SC31b is is a budget light but it’s certainly not low quality. It has O-rings and rectangular threads.
The anodising looks good and allows the light to be locked out with a quarter turn of the tail cap.
There are springs at the head and tail, both of which are gold plated.
The SC31b is a standard straight tube 18650 light, very similar in dimensions to the Convoy S2.
The clip is very strong and is a challenge to take off. The pocket clip isn’t “deep carry” and the light protrudes an extra 20mm past the top of the clip. It’s not a reversible clip, so the light can only be carried in a pocket head down. This means it can’t be clipped to a cap either, though it be too heavy for this anyway. Sofirn could have made another space on the body for the clip to make it reversible without affecting the design.
Sofirn have a fairly standard UI on the SC31b that’s easy to learn and doesn’t confuse people.
- Click on, click off
- Hold to change modes
It has mode memory for all modes except strobe. That means you have to go through high if you want to get to the lowest modes. Disconnecting the battery doesn’t reset it either.
After clicking on, it takes about 100ms to actually turn on. This is probably so you can do double click to go straight to strobe without it turning on first. I’d rather the first click turned it on immediately though, even if you wanted to use strobe. It does the same when turning off too, and allows you to get to strobe with a double click from any mode.
When turning on the blue indicator LED on the button shows the cell power for a few seconds before turning off. High/medium/low voltage is displayed as constant blue, slow flash and fast flash respectively.
Holding while off turns on the button indicator light in a “breathing” mode. Roughly a 3 second gradual pulse. This serves as an auxiliary light to help find it in the dark. You then have to click to turn this off, before you can click again to turn the light on. A double click from breathing mode turns the light on too (not on strobe). This means that breathing mode is deactivated whenever you use the light and doesn’t automatically reactivate when you turn the light off. I’d like to see the option to leave breathing mode on all the time.
I’m not a fan of mode memory but some people love it. I’d rather the light went to medium by default and used shortcuts like hold for eco and double click for turbo.
Light (modes, comparisons, beam, brightness)
1000lm is pretty standard for an 18650 light now. This isn’t a hot rod and isn’t a slouch. The modes are well spaced but the SC31b would benefit from a moonlight or firefly mode around 1 lumen.
From what I can tell, this one uses a XP-G3, which isn’t my favourite LED. It’s cool white but the “CREE rainbow” isn’t as evident as it is with some XP-G3s. The XP-G3 is a small LED, so the SC31b throws quite a long way for its size. Comparing to other lights, the SC31b has a colour temperature a bit over 6000K.
AliExpress have a listing for the SC31b with a Luminus SST20 emitter available in 4000K (warm white) and 6500K (cool white).
Output, runtime, and efficiency
Sofirn lists the following runtimes. It’s not clear if this is with the included 2200mAh cell or with a higher capacity one.
|Eco||10||80h (over3 days)||30m / 225cd|
|Low||150||8 hours||88m / 1950cd|
|Medium||400||2 hours 30 min||134m / 4500cd|
|High||1000||1 hour 20 min||207m / 10750cd|
The high mode will step down after a few minutes but I haven’t tested how quick or far this is yet.
Other lights to consider
- Convoy S2 – the standard in the flashlight world. No USB charging but has lots of LED options
- Wurkos FC11 (Amazon UK, Amazon US)- very similar to the SC31b but has USB-C and an LH351D LED
The Sofirn SC31b is all round a pretty good light. There’s room for improvement but at it’s price you can’t beat it. It’s a great light if you’re just getting into 18650 lights and as a gift it’s an eye opener to how bright 1000lm really is.