Sofirn C8F 21700 Teardown and Review

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 sofirnlight.com 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

Edit:

Bypassed tail spring

Turn On - 3850
30 Sec - 3570

Now that’s more like it!

What about stock, with no alterations? Are you seeing a bump in output?

Turn On - 3290
30 sec - 3070

Okay, I suspect that they improved the driver contact and got the retaining ring to clamp it down tighter.

3370 at 30 sec with the Sofirn 21700

Wanting to add that many have previously said Sofirn were using 40T’s but this isn’t the case. I ran tests on my CBA and the 40T is much much better

what do you mean by “blue’s spring”?

BlueSwordM sells his custom high current springs

ahh, i see. Did your c8f already have the double tail spring before or was it the single spring?

Dual tail stock I think it was the old 18650 c8f that had two single bypassed springs

So I just received my Sofirn C8F bought from Sofirn’s AliExpress store on 01\06\2020. The tail cap has the dual springs, but on a freshly charged LG M50T 21700 cell, I’m reading about 2300 lumen on my Texas Ace calibrated lumen tube. One of the holes in the retaining ring looks damaged and has a gash through the ring. Anodization looks like one small area has a rub mark. Will be contacting them. Will be trying a 30T cell on it to see if it’s the batteries internal resistance. Not happy about the retaining ring looking damaged, or the output. Does anyone know if the brass retaining ring from a Convoy can be used in place if the soft aluminum? Hopefully I didn’t get one with an old driver. Will be contacting Sofirn to hopefully get this resolved.

The old driver was still better than the numbers you’re seeing.

Make sure you clean all the contact areas and that the retaining ring is tight. If I loosen mine or cut the spring bypass I get approx 2000. Try redoing the spring bypass as I always get less with the factory job.

Thanks Funtastic,

Yeah I’m wondering if I do anything to it if they will honor warranty? :). I’ll try tightening the retaining ring, although one of the holes is damaged so not sure how tight I can get it. The bypass can be redone too. As long as the driver is correct the rest can be corrected (I hope)

The M50T has only a 7.3A rating so that looks to be the issue

When I first tested my Samsung 50E I only got 2200lm. After fiddling with the driver retaining ring I got 2700lm. A 30T squeezed out a few more at 3100lm. So the M50T is not that big an issue.

It’s just odd since my new lot are much better.

I’ve still got the old version if you want pics of both drivers

What lot are you refering to?

I never felt it was a driver issue, it seems to be a contact issue around the driver retaining ring.

I have one C8F from a previous batch that achieves 2700 and my new batch that gets 3070. With Blue’s spring and bypassed tail spring 3570 at 30 sec.

Something has changed, not sure what. My old C8F’s retaining ring is very tight and can’t get any movement of the driver whatsoever.