[Review] Sofirn SP40, an 18650 (or 18350, or 16340) powered right angle light

Sofirn SP40 Right Angle Light

MSRP: $31

Manufacturer page: N/A

Store link: https://www.amazon.com/dp/B07RQ68KPB

I was sent this light to review free of charge but, as always, I've tried to be as unbiased as possible.


The Sofirn SP40 is a 1x18650 right angle light that uses a cool white XP-L emitter and produces a maximum output of 1200 lumens. It can charge cells via a micro USB port on the back of the head, and comes bundled with a 3000mAh cell so you can use it right out of the box. Also included is a short tube, allowing the use of 18350 and 16340 cells.

Album link


Unlike most of Sofirn's other recent lights, the SP40 comes in a plain cardboard box with the contents padded with bubble wrap and foam.


The box contains:

  • Sofirn SP40 right angle light
  • 3000mAh Sofirn branded 18650 cell
  • Insulator disk
  • Short tube
  • Headband
  • Pocket clip
  • Two spare o-rings
  • Silica gel packet
  • Contact card
  • Manual


The SP40 has all of the hallmarks of a Sofirn flashlight. Smooth, flawless, anodizing, somewhat noticeable machining marks, beefy o-rings and square cut threads, both lightly pre-lubed. It's built up to the standard Sofirn has set for itself. Due to the charging and a fairly deep tailcap, the SP40 is a bit longer than other right angle lights on the market.

The tailcap is mostly covered in diamond knurling, with a smooth band on the side of the tailcap facing the body. The bottom of the tailcap is flat and the light tailstands well. The inside of the tailcap is typical for an e-switch light; just aluminum with a gold plated spring.

The 18650 tube has two clip grooves, one on either end, and the rest of it is covered in the same diamond knurling as the tailcap. The threads on the ends are trapezoidal and the included o-rings are beefy. They come pre-lubed, but mine weren't quite lubed enough. The tube is completely reversible. The shorty tube is the same in all aspects except that it only has one clip groove.

The head of the light has the optics facing out the side, with a slightly proud screw-in bezel. Opposite that is the charging port. The button is on the top of the head, similar to a Zebralight headlamp or Olight's H2R. "Sofirn SP40" is silkscreened under the optic, and the CE, RoHS, and "don't throw this away" mark are on the back under the charging port.

The emitter is behind a glass lens, o-ring, and a lightly orange peeled reflector. It's very well centered. The design of this assembly is great, with the lens pressing down on the o-ring to create a good seal. I left it submerged overnight and no moisture got in.

The charging port is covered by a thick rubber flap. It sits in its recess very securely, and the rubber bit keeping it attached to the light is thick enough that I'm not concerned about it tearing. Due to how recessed the charging port is, not all micro USB plugs will be able to fully seat into the port. Most will be fine, but there were a couple in my collection that didn't quite reach.

The button is an electronic switch with a rubber boot, held in by a screw-in retaining ring. There are two sets of indicator LEDs under the switch; a pair of red and a pair of green. These light up to show the battery level and the charge status.

The driver seems to be either press-fit or glued in. It also has a gold plated spring on it, which allows the use of any sort of li-ion cell that will fit.

Clip and Headband

Much like other right angle lights on the market, the SP40 comes with a headband and a clip, so you can use it as a headlamp or carry it around like you would any other flashlight. It's one or the other though. You can't use the headband and the clip at the same time.
The clip is one of Sofirn's standard steel clips. It's beefy and it does its job well. In the past I've praised these clips for being very sturdy and not coming off of the light accidentally. This is a double edged sword in this case. The excellent clip retention means that it takes a fair amount of effort to remove the clip from the light, which isn't ideal if you want to go back and forth from using it as a headlamp and a pocket light.

There are two grooves for the clip on the 18650 tube, one on each end. I've found that the most convenient method of carrying it for me is with the clip attached to the head end of the tube, facing the tail. This leaves the entire head poking out of my pocket, but it also means the light won't get activated by the stuff in my pocket. I haven't found a good way of clipping the light with the short tube. The most secure way (clip groove at the bottom, clip facing head) isn't great. The grooves milled into the head grab at your pocket when you clip and unclip the light.
In the future, Sofirn should consider including a deep carry clip with their right angle lights. This would allow for a much more stable head-up carry.

The included headband is of the typical two strap design and it smells like balloons. It's a very tight fit around the light, and holds it in position very well. It comes pre-assembled, and the straps are sewn together in some places, so you can't take it off of the headlamp mount. It does its job well. I have no complaints.

Battery and Charging

The SP40 can run off of protected or unprotected flat top or button top 18650 cells with the long tube, or any 16340 or 18350 cell with the short tube.

The included 3000mAh cell is from a different supplier than Sofirn has used in the past. The cell itself is in a white wrap with a bar code and text reading "01VCEAJZ1101B19150003031". I couldn't find any results for this cell.

Capacity and internal resistance were tested on an Opus BT-C100. Capacity was accurate at about 3000mAh, but the internal resistance was very high, at about 80mOhms. For comparison, a Sanyo GA is about 40mOhm, and a Panasonic NCR18650B is about 45mOhm. This means that the cell won't be capable of putting out a lot of current. This number may be due in part to the button top that was added onto the cell.
The head of the light has a micro USB port that will charge whatever cell is in the light. It charges cells at 0.9A, which is fine for 18650 cells, but if you're using an 18350 or a 16340 with the short tube, that charging current is going to be way too high. Charging terminated at 4.17 in my testing, which is a bit lower than it should be, but it'll make no actual difference in usable capacity. Charge status is given by the indicator switch. The light will turn from red to green when it finishes charging.
The indicator LED also indicates the status of the cell as the light is being used. If the cell is above 3.3V, the indicator LED will be solid green. Between 3.3V and 3V, the indicator will flash red at about 1 Hz. Below 3V, the red will flash faster at about 2 Hz. It has integrated LVP which kicks in at about 2.7V, which is a safe cutoff voltage for li-ion.

Modes and UI

The SP40 has four modes, Low, Medium, High, and Turbo. From off, a single click will turn the flashlight on in the last non-Turbo mode used. Pressing and holding from that point will rotate through the modes, L->M->H. Double clicking will go to Turbo, and a single click from Turbo will return to the last used LMH mode. A single click from LMH will turn the light off.
The mode spacing between Low, Med, and High is good, but the lowest mode is too high. 5 lumens is a lot, especially when the light is focused into a hotspot. A moonlight mode would have been great.


This is the first high powered headlamp I've owned that's used a reflector, and I'm not sure how to feel about that. The reflector means that the SP40 has a traditional flashlight beam with a hotspot and flood. This is great for pointing stuff out and looking at stuff a bit further away, but not as optimal for setting up a tent or collecting firewood. It fills a slightly different role than other headlamps.
The XP-L is what I'd consider cool white. Probably 5500K. It has the tint shift you'd expect from an XP-L in an OP reflector; a bit warmer in the middle and a bit cooler on the outside. No PWM is visible in any mode. Here it is compared to my 4000K 219C H03.

Modding Potential

Disclaimer: Do this stuff at your own risk. If you mess up and break something, that's on you. Also, doing any of this will totally void your warranty.

Driver: Press fit
MCPCB: 17mm

The emitter is easy to swap, but with the driver being press fit and having integrated charging, I don't think a driver swap would be possible. I put an LH351D in mine and the beam is so much nicer now.

Bottom line:


  • Good build quality
  • Integrated charging
  • LVP


  • Cool white
  • No moonlight mode
  • Clip isn't very well suited for the light

Thanks for reading my review! If you have any questions about this flashlight, I'd be more than happy to answer them.