Sofirn C8F 21700 Teardown and Review

Yes it's been mentioned by… yourself!

Cheers ^:)

Oh yeah! I forgot. Lol

I recently ordered another Sofirn C8F-21700, and noticed that the tailspring is now not factory-bypassed (left), but instead uses a double-spring (right).

I think they now have the same tailspring as the Sofirn C8G (which also uses the double-spring). (I tested that the C8G and C8F-21700 are interchangeable)

Any idea if which one is better? Which can pass higher current?

I notice that Sofirn's factory bypass wires tends to get detached when using high-drain batteries (at least that's what happened on the Sofirn C8A and Sofirn C8F-18650 when I was testing Turbo mode for a bit longer time, and notice the factory spring-bypass wire on both sides got detached probably due to heat -- and I'm not good at soldering small parts)..

Properly done spring bypasses require wire coiling. Without it, chances for the wire to break are substantially higher. So either do a custom spring bypass, or use the double spring is my advice.


As Barkuti said. Properly done wire bypass gives higher current but double springs far more reliable. Even a properly done wire bypass can break over years.

User BlueSwordM can provide some nice high current springs. Check this thread:


I hate putting springs on boards like this. They always seem to fall in that green solder mask area. Not even sure what the purpose of making it like that is

Hello everyone, where to buy a reflector “orange peel” for this flashlight? I really need this reflector! Thank you.

I’m not aware such a thing exists.

I’m looking at the C8F on the Sofirn site. They’re selling various tints.

I’m wondering if the issues described in this thread have been resolved by Sofirn during 2019. I’m looking at the 4,000k and thought they were only selling cold white when I looked last year. Or if this is a more recent version. I saw them selling prototype LT1’s on the same page, so I don’t think I can rely on this being current stock.

I’d be even more interested in the SP33 that one only comes in cold white and I don’t know how to do emitter swaps.

In ‘The general Sofirn development thread’ Barry from Sofirn wrote that they are now offering hosts and custom leds and tints in their flashlights.

The Sofirn C8F can be ordered with LH351D’s now.

The C8F never really had any issues or problems. They simply gave it too high a Turbo rating. They should not have said it’s 3500 lumen. More realistic would be 2600lm. Some get a bit more output. If they had rated it lower, all would be fine. I kind of prefer this lower power version over my modded high output version. Stock it didn’t get hot so fast and Turbo was more usable. After I did all my mods to increase output to 3100lm it just gets hot too quick.

I never considered this stock 5700K a cool white. It’s more NW. A bit of yellow instead of blue. I like it.

Like Skylight said, you can contact Sofirn at their Aliexpress store and request a different emitter. They will probably be busy with holidays until early Feb, though.

I dont know what other tints they have for 50.2. If it’s the SP33 v3 it’s a 3v led which is very new and limited in tints. If it’s the SP33 v2 (6v), there should be more options.

To do an emitter swap first requires you to unsolder two wires on the led mount called the (mcpcb). If you buy a new mcpcb with the new leds already mounted, you swap the boards and solder the two wires back on. Pretty simple.

Things are a lot more tricky if you can’t buy the LEDs already mounted to the new MCPCB. In this case you have to reflow solder the old LEDs off and the new LEDs on. This is a little more advanced. It requires the use of a hot air station, a hot plate or maybe just a controllable heat source. The process and technique is what is key for a good reflow.

Thanks, Jason.

I have some lights on which I’d like to change the tint and will approach that at some point.

I have lots of lights around 5,000k and I’m trying to migrate to warmer tints, which would be the purpose of this purchase.

My apologies if this was already noted above and I missed it, but does anyone know the diameter and thickness of the lens on the C8F? It would save me a bit of time if someone knows this already. I am looking to put a high quality yellow lens into a C8F - fog and heavy snow at night (star field effect) render my higher lumen LED’s ineffective. I would like to swap out the lens for a yellow lens and see what the result is. Thanks for any info or advice - I am a total novice and am just at step 1 (an idea) of trying to pick my way through any modifications to a light.

My 4,000K C8+ is good for fog. Warm, focused beam.

42mm x 2mm

Thanks for sharing that info - I will definitely take that into consideration. I am looking for something like the old Hella or PIAA fog yellow. My led fog lights on my car cut glare big time in fog and snow - so I thought can I come somewhat close for a flashlight and maintain lumen output? We get some driving snowstorms where I live and taking the dog out at night - it would be great to be able to turn on a light without it feeling like I am looking into my own light on strobe effect. So I thought I would give it a go and report back if it seemed newsworthy. I can’t do all the fancy things most of you do - but I could make one small contribution to the collective good - and report the result good, bad or otherwise.

Thanks for sharing the specs! This is a huge help on my quest!! We shall see if it turns out to be worthy of a minute of my time - you don’t know until you try. :slight_smile:

Once I tried to paint a glass lens with yellow felt pen. If you have a totally yellow lens the light is yellow as well. Half yellow, half transparent is not bad. However, it does not even get close to a real warm white emitter.

The C8F can be purchased on with 3000K XP-L or 2700K LH351D.

2700K or 3000K SST20 should be nice as well like in the Fireflies ROT66, E07 or Emisar D4S, D18.

I recently purchased 8pcs C8F and it’s been improved big time

Using the 40T and Blue’s spring installed

Turn On - 3500
30 sec - 3270

Brand New C8F from 4 months back with the same as above

30 sec - 2700


Bypassed tail spring

Turn On - 3850
30 Sec - 3570

Now that’s more like it!