Sofirn SP33 V3 Review (3500 Lumens, Multi battery compatible, Very Affordable)

Sofirn has made an upgrade to their SP33 light after taking feedback from the flashlight community and come out with the SP33 V3 edition. It can use a several sizes of batteries such as a 26650, 18650, and even 21700’s. It features a Cree XHP50.2 at 3V LED and produces 3500 lumens in a pretty compact light and a very budget friendly price. Thanks to Sofirn for sending this to me to check out.

Sofirn has provided a nice discount on this light that I have listed in my Youtube video if your interested. It is an affilate link.

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Packaging & Accessories
The SP33 has a bit of a more retail looking box then we have seen from them in the past. It’s a black and orange hanger box but it doesn’t have a photo of the light on it, just a night shot showing a very bright flashlight. Accessories that are included with the SP33 V3 Kit are The 5500mAh 26650 battery, 18650 battery adapter tube, USB-A to C charging cable, manual, and a lanyard with a couple extra o’rings.

The SP33 V3 is made of 6061 aluminum and hard anodized in black. Machining is good for the price range, with no major concerns. Starting at the tail cap, it has a crown and one side has 2 holes for a lanyard attachment point. They are just a little to small to easily fit paracord in, but you might be able to if you are patient and creative. Knurling is straight and there are a few flats in place for style. This is different from the rest of the light but provide function. Inside there is a single short fairly stiff spring that provides compatibility with the many different battery types this light supports. Threads are ACME cut and were dry in my example.

The body tube is reversible and has a decently thick walls. There isn’t a place for a clip but that’s ok for a light of this diameter in my opinion. The knurling is standard diamond knurling and is done in four panels around the light and is of medium texture.

The head is a solid piece. In the center you have the flat plastic e-switch button with an LED in the middle used for power indication. Around the hexagon there are small areas milled in to help with cooling and give style. Opposite the button is the USB-C port for recharging. The silicon cover here is a bit large and does protrude slightly from the lights back, enough so it won’t sit flat on this port but in the hand this works fine and stays out of the way.

The V3 features a deeper stainless steel bezel with a few short but long crenelations. This has been lengthened on the V3 version. The lens looks to be uncoated mineral glass and is fairly thick. The reflector underneath is deep with an orange peel.

Size & Weight
I measured the length of the light at 126mm, maximum diameter at 37.5mm, minimum diameter at 32mm. Weight with the included battery is 229g.

I don’t have a lot of other great 26650 lights that are similar sized to compare it to. What I do have is the Wowtac A4 V2 I reviewed recently. It’s similar in length and diameter but the head is much larger. I also have the Sofirn SP36 I reviewed last year, its similar in length but has more diameter due to it’s 3 18650 batteries.

Not much to say on retention here, there isn’t a place for a clip on the light, and it doesn’t come with a holster. The tail cap does have a place for a lanyard to attach if you wish. The light does tail stand without an issue.

LED & Beam Shots
V3 of this light is using a Cree XHP50.2 LED at 3V instead of the 6V version of this led. Tint is listed at between 6000-6500k, so cool white. On lower powers I do notice a bit of green tint shift on my example but it’s minimal. On higher powers you do notice tint shift across the beam. I would categorize the light as an all purpose beam, It’s fairly wide and the hotspot is so broad it’s not a thrower, yet it goes a good distance as you can see in my night shots. Sofirn quotes a throw of 275 meters and I think that’s a good number that’s in the ballpark.

V3 is using a FET driver instead of boost driver meaning it’s drawing more current from the battery thus the higher turbo output that’s seen here. You are going to want to use a good high quality high drain flat top battery with this light for maximum performance. It can accept 26650’s of all types, 18650’s of all types with the included spacer, or unprotected flat top 21700 batteries. The light has PWM on all modes according to my scope and solar cell setup. That said it’s pretty fast and my eyes or camera don’t notice it.

Output is listed as:

  • Turbo 3500 Lumens
  • High 1600 Lumens
  • Medium 450 Lumens
  • Low 150 Lumens
  • Moon 1 Lumen

Heat and Runtime
The SP33 V3 features Advanced temperature regulation without timed step downs, instead output will decline with the drivers internals reach 55C. Brightness will increase again when temps decrease, and we can see this in the runtime graph, as it’s a very seesaw motion. On average you’re seeing maybe a 20% swing in relative output over the life of the battery after the initial turbo step down. I didn’t notice it unless I was really focused on it on a 25 minute walk with the light. Turbo did start stepping down due to heat at 1 min 45 seconds, taking a little over a minute to step down to 18% relative output to cool. From here you can see on the graph it went up and down in terms of output as the flashlight regulated its own heat.

Total runtime on the included 5500mAh battery was 3:24:00. FL1 was at 3:11:00 and the maximum temp I saw during my runtime on the exterior was 48C or 118F so definitely very warm. All temps were taken at my ambient room temp of about 25C.

User Interface
This light has 2 UI modes, default mode (mode 1) is a stepped mode that works logically. It has moonlight, low, medium, and high modes with memory and Turbo without. A single click turns the light on from off, and holding the button down cycles through modes. Long press when off turns on Moonlight mode and double click goes to Turbo. Triple click to go to SOS/blinking modes.

The second UI mode is a ramping mode. To switch between the 2 modes when the light is on do a quick quad press. Ramping is like many other ramping modes with a flash on both the top and bottom end. For me while I like being able to set brightness exactly where I want it, I don’t love the speed of the ramp here, it’s a little on the slow side.

There is an electronic lockout when the light is off just quad click quickly. You can also mechanically lock it out with a slight twist of the tail or body tube. This is useful for such a powerful light os you don’t burn a hole in a bag or coat.

The light isn’t picky on the size of batteries used in the light diameter or size wise. It can accept 26650’s of all types, 18650’s of all types with the included spacer, or unprotected flat top 21700 batteries. The later having the most slop in the tube due to not including an appropriately sized spacer. I used the supplied 5500mAh Sofirn 26650 battery for my charging tests. LVP came in on the light at 2.895V, so a little lower then I prefer but acceptable. The battery measured as fully charged at 4.15V.

The light does use USB-C for recharging which is nice to see. However it requires a USB-A to C cable (Supplied) to charge, and isn’t compatible with a C-C cable. When charging the small LED in the center of the button blinks red, and goes blue when charged. From LVP to full the light took 3 hours, 30 minutes. Maximum charging rate was 1.7A.


  • Great budget friendly price for a lot of light in a good overall package.
  • Is available in a few different versions, and battery options.
  • UI is more “beginner friendly” than Anduril firmware.


  • Still not fully utilizing USB-C to C, requires a USB-A to USB-C cable to recharge.
  • Very active thermal controls, with a good amount of change in output.
  • No Neutral White tint option that’s widely available.

The Sofirn SP33 V3 is a low cost light with a lot of Output. Sofirn lists the light as making 3500 lumens. It runs on 26650, 18650 and some 21700 batteries so it’s widely compatible with the 3 most popular battery sizes today.

It has features not usually found in this price category like USB-C charging (not compatible with USB-C PD (C-C) charging), active thermal controls, and a stainless steel bezel. The active Thermal controls are pretty reactive but they are smooth and I don’t notice it with my eye as much as the graph shows. I wish it was more widely available in Neutral white, they list it as an available option on their AliExpress store but I don’t see these available from other retailers.

For the money especially with the discount Sofirn has provided makes this a really great value for the complete kit. It fits well in my hand and produces a ton of light. I can easily recommend this as a great high output budget light to pick up.

Thanks for the review. I’m a big fan of this light. It’s lightweight, small for a 26650, and gets bright. Even the CW version seems more NW-ish to me. It’s a great backpack light. It’s coming camping with me tomorrow over other lights.

The SP33 seems like it should be a good light… but wow, that runtime graph. Others have noticed the same thing, and it’s probably the least stable thermal regulation I’ve ever seen on a flashlight. Kinda wondering how that got through testing.

Ya It’s the most active I have seen with the testing method I have now.

Great review- very thorough! :+1:

I am waiting on a 5k version of this light. It is stocked out along with the k5 SD05 dive light (which I think also uses the 3V emitter?). I have the original SP33 with an XP-L2 (or it might be an XPL); got it several years ago. Its been a handy light since doing duty at the back door for checking varmints and stepping out for the occasional cigar :smiley:

Also have the V2 and that’s a good pack light with really good run time on high (steady 900 lumens if I recall). I wonder with the size available for the driver if there may be an Anduril version in the future? But with 21700 batteries around 5k (and 26650s phasing out), maybe not.

I understand the thermal “swing” can be an issue for some, but the V3 with a good turbo output is still a light I want. When out camping/hunting this light has plenty of output where I doubt I’ll notice the delta in thermal regulation- and I’ll appreciate that bright turbo when needed (usually for a short time of course).

I’ve been weighing the SP33v3 against its half-sibling, the EC01, for my next purchase.

Between two very similar lights, the poor hysteresis in the SP33’s controls is turning out to be the biggest factor in favor of the latter.

If I understand correctly, the EC01 runs fairly old firmware from the SP36. It’s not really built for use on a smaller light, and isn’t calibrated well. Its thermal regulation probably isn’t great either.

This might get fixed eventually, but isn’t yet.

Personally, if I was looking for a 26650 light similar to SP33, I’d go with a D4Sv2. It costs a bit more and doesn’t have built-in charging, but it’s otherwise a pretty solid upgrade.

I like both - the SP33 V3 and the EC01. Just got my 2nd EC01 in, this time the 5000K version. Both lights are great deals for what you are getting, but yes, not thermal regulated well at all.

Yes, my understanding is that it uses an older version of your firmware, and the regulation isn’t great, but it doesn’t vacillate as frequently as this, nor noticeably, as I’ve seen mentioned in another review.

Ironically, the older SP33v2 steamrolls them both (pun intended) in this respect, but I’m not really certain about its availability, or gamble that I’d receive the desired version.

Other factors are playing a role as well, and I wouldn’t regret either choice, but the number of checks in the other column are totaling higher, and this one is more emphatic.

Budget lights come with compromises, and working through which are more acceptable is part of the game.

I’m aware that there was a period of controversy over the existence of the 5000k version, but that it was supposedly resolved.

Even so, the end result was that the 5000k version didn’t turn out to be much different that the 6000/6500k version. Is that what you’ve found?

Yes, very disappointed. After careful side by sides, I see no difference

Do you think the EC03 is running the same sp36 version as well?

If I understand correctly, yes.

In case it helps, I’ve been trying to track these things in a product firmware map.

Regardless of the thermal regulation being a bit of a see saw, overall I like this light. I’ve got the first version too and I think that Sofirn made some nice advances through the versions. I like the UI because it’s intuitive and I think I prefer the stepped mode over the ramping, but I’ll keep switching back and forth after I use it some more. I love the double click to turbo and the long press to moonlight. More companies oughta follow this. The ramping is faster than earlier Sofirn lights but a bit more speed to match my Q8 or FW3A and others wouldn’t hurt.

The things I really like are the use of different batteries, the heft of it and how it doesn’t seem to get into the danger zone with heat like some other smaller/lighter lights with similar lumen output. I feel ok handing this to a newbie after a bit of a lesson where I wouldn’t think of doing that with my Emisar D4 or other pocket rockets. A 26650 sized light just feels good in my hand. I’ve used it a good deal walking the dogs and walking the property to see if I can spy different nocturnal critters. It’s not for pants pockets but I did find a holster that I used for a Haikelite SC26. I upgraded to one of my Shockli 5500mAh cells (although the supplied battery works fine in this light as well as the first SP33 I have). I’m sure it’ll continue to see use around here.I guess lights like this just make sense. It’s a good price, very good output, easy to use, USB with a quality rubber plug (that some will like) and it’s flexible (cells and UI).

Thanks! I may eventually take a stab at modding your software. If i could just plug it into usb to update firmware i’d be hacking away already.
I wouldn’t call my self a coder but have worked with enough to understand the basics.

I wish they would put a little effort into modding your freeware, it seems sometimes they can’t be bothered to even post a link?
I would think some intern could take it home for a few days and just keep guessing and checking to modify software would be pretty easy and cheap, but it seems there’s just a rush to plop and drop to get the next flashlight release out the door.

Just curious, are those remarks prompted by some indication you’ve received that future production will incorporate a newer version?

Nice review!

Very neat PWM and runtime graphics. :+1:

If I understand correctly, newer production runs will use newer firmware.

Basically, I found out the IF25A exists because someone asked me why its thermal regulation wasn’t working. Also within a few days of that, I discovered that the SP36 was using a really old version of Anduril, and discovered the EC01 and EC03 are made by sofirn. So I contacted sofirn to get the firmware updated and get the license violations resolved. With any luck, maybe the smaller lights can get their own firmware too, instead of using something calibrated for a much larger light.

I don’t have the details though.

Good to know. Thank you for sharing that information.

I used zak wilson’s ‘ceilingbounce’ Android app and “ceiling bounce” the flashlight (almost fully-charged batteries, not particularly high-drain batteries used, since the flashlights were not cooled and was in a small enclosed room with no airflow, and ambient temperature is quite hot in our country all year long.)

(I didn’t do runtime until low-battery, but instead stopped manually when I notice the output was already very low and doesn’t seem to be moving much)

SP36 BLF Anduril runtime (first several minutes only)

Astrolux EC03 (uses Anduril) runtime (first several minutes only)

Yeah, that’s definitely old firmware which wasn’t intended for production use. I fixed it a few months after that for the FW3A release, and the thermal code has been rewritten twice since then. The current code isn’t perfect, but it’s a lot better than it was.