Sofirn C8F 21700 Teardown and Review

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YogibearAl
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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.

Funtastic
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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.

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YogibearAl
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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)

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YogibearAl wrote:
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

Texas Ace Lumen Tube calibrated with maukka lights

New Zealand store – https://www.piercingthedarkness.co.nz (NZ customers only)

JasonWW
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Funtastic wrote:
YogibearAl wrote:
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.

Texas Ace Lumen Tube and JoshK Sphere calibrated with Maukka lights

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Funtastic
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JasonWW wrote:
Funtastic wrote:
YogibearAl wrote:
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

Texas Ace Lumen Tube calibrated with maukka lights

New Zealand store – https://www.piercingthedarkness.co.nz (NZ customers only)

JasonWW
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Funtastic wrote:
JasonWW wrote:
Funtastic wrote:
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.

Texas Ace Lumen Tube and JoshK Sphere calibrated with Maukka lights

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Funtastic
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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.

Texas Ace Lumen Tube calibrated with maukka lights

New Zealand store – https://www.piercingthedarkness.co.nz (NZ customers only)

YogibearAl
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Notice how my retaining ring is a bit messed up? One hole drilled through side wall and the other is very close.

– Driver retaining ring

– Scuff off of anodizing underneath the “hot” label.

I think at a minimum I would want to get a new retaining ring. The packaging and all other accessories looked new. But I’m wondering if this was a refurb of the original batch to replace the driver? Not sure. But none of my Convoys came like this. I’ll try again with my 30T cell fully charged tomorrow as far as the output is concerned.

Funtastic
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Nothing off looking though. I’m a dealer in New Zealand and quite often I get scratches and off centered holes in retaining rings on Sofirn lights. Sofirn used to apply black repair stuff on scratches in hopes of not noticing it. I had heaps on the old 18650 C8F’s until I complained and not long after I stopped seeing it

Sofirn offer excellent lights for the price, if you want everything spot on then look elsewhere

You could message Sofirn about the scratch and see if they’ll give a small refund

Texas Ace Lumen Tube calibrated with maukka lights

New Zealand store – https://www.piercingthedarkness.co.nz (NZ customers only)

JasonWW
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Funtastic wrote:

My old C8F’s retaining ring is very tight and can’t get any movement of the driver whatsoever.

The question, is the ring tight against the driver or tight against the threads?

I think the threads bottom out right as the driver just starts to get squeezed. This prevents the driver from being squeezed hard like in a normal flashlight. IDK, this slight tolerance issue might be why some lights draw more amps than others and why the amp draw can vary when fiddling with the retaining ring (at least in my case).

I think YogibearAl should try loosening the ring and cleaning the edge of the driver on both sides, clean the ring and the flashlight head where the driver presses against, then tighten it up and see if the output increases.

His ring looks perfectly functional. Someone used pliers and squeezed too tight and that caused those gouges. No big deal, though.

Side note-

Anyone that would ask for a small refund because their light has a scratch or imperfection on it is a whiney little baby – in my opinion. It’s gonna get damaged the first time you drop it, so what’s the difference? SMH

Texas Ace Lumen Tube and JoshK Sphere calibrated with Maukka lights

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Funtastic
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JasonWW wrote:
Anyone that would ask for a small refund because their light has a scratch or imperfection on it is a whiney little baby – in my opinion. It’s gonna get damaged the first time you drop it, so what’s the difference? SMH

Hmm, if it’s for personal use then yes, I wouldn’t bother, not for Sofirn prices. When selling them and I get some damaged ones I’d ask for replacements or a discount. I don’t get much cheaper pricing than everyone else. I do get wholesale pricing but Sofirn is barely making much so the difference isn’t much. Glad I don’t live in the US as I doubt I could resell and compete with Amazon. No Amazon in NZ yet and the Aus one doesn’t ship here

Texas Ace Lumen Tube calibrated with maukka lights

New Zealand store – https://www.piercingthedarkness.co.nz (NZ customers only)

YogibearAl
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OK I verified this is a new driver, and after cleaning and tightening the retaining ring, it is at 2500 lumens on start up and drops down to about 2400 after a bit, so improved by almost 200 lumen.

I don’t care about the cosmetics, but just comparing to the Convoy C8+ I recently received they look a little better and is hitting close to the 1800 lumen advertised. Maybe I just need to reset my expectations? I’m not asking for refund. I just would like to get closer to factory rated lumens. Will try with the 30T tomorrow. The LG M50 definitely not the best cell for high output. Stay tuned Smile

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YogibearAl wrote:
OK I verified this is a new driver, and after cleaning and tightening the retaining ring, it is at 2500 lumens on start up and drops down to about 2400 after a bit, so improved by almost 200 lumen.

I don’t care about the cosmetics, but just comparing to the Convoy C8+ I recently received they look a little better and is hitting close to the 1800 lumen advertised. Maybe I just need to reset my expectations? I’m not asking for refund. I just would like to get closer to factory rated lumens. Will try with the 30T tomorrow. The LG M50 definitely not the best cell for high output. Stay tuned Smile

Your C8+ SST-40 is hitting 1800 at 30 sec or turn on? I get 1600 at 30 sec using the ramping driver from Convoy. That’s with a 30Q so maybe would get higher with something better

Texas Ace Lumen Tube calibrated with maukka lights

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YogibearAl
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My C8+ with ramping driver is completely stock. Starts out at just above 1800 and drops steadily, but at 30 seconds mine is just around 168x lumen. I am also using a 30Q measured with a Texas Ace Lumen Tube received less than a week ago, calibrated with Maukka lights just like yours. Its pretty consistent.

My comparison readings back to back with the Sofrin C8F is how I knew my Sofrin was reading really low. Even my Convoy L6 boosted is reading near others reports at just over 4500 lumens at start up using KeepPower 5500mAh 26650. So I know my measurements are somewhat accurate.

YogibearAl
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Ok finally got around to charging my 30T. Start up 2810 and 2570 @ 30 seconds. So best numbers so far. Will try cleaning some more and lower gauge bypass wires, to squeeze a little more it of it. So seems like ok.

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That’s so strange how mine perform at 3070 at 30 sec stock. You must have received the older revision unless I got lucky

Texas Ace Lumen Tube calibrated with maukka lights

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YogibearAl
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Well I read the rest of this thread and know that the driver looks new, so should be getting better numbers. Still satisfied with overall performance. After cleaning and tightening I noticed that the retaining ring isn’t fully contacting the driver board evenly. There is obvious uneven rub marks around the outer edges of the board trace. There is a spot with almost no scuffs on it, telling me it isn’t fully flat.

I’ll figure it out. This forum has helped a lot with ideas. Surprised to see the jump in performance from the M50 to 30T. Maybe order another one when on sale to compare. :). Overall I still really like it. I use it primarily in ramping mode.

Phoneas
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Pretty simply question for those experienced at tearing down lights – I want to swap out the lens on my C8F – if I don’t have any tools specific to flashlight modding, is there any tool in the typical household tool box that I can use without damaging the light and retaining ring? I was thinking locking pliers wrapped with electrical tape on the teeth with just enough pressure to get a grip to twist without denting or crushing it. This doesn’t sound like a good idea. Perhaps there is a tool at harbor freight I could buy? Any advice would be most appreciated. Also, will I encounter any issues or concerns by swapping the lens – leds or anything else?

JasonWW
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Phoneas wrote:
Pretty simply question for those experienced at tearing down lights – I want to swap out the lens on my C8F – if I don’t have any tools specific to flashlight modding, is there any tool in the typical household tool box that I can use without damaging the light and retaining ring? I was thinking locking pliers wrapped with electrical tape on the teeth with just enough pressure to get a grip to twist without denting or crushing it. This doesn’t sound like a good idea. Perhaps there is a tool at harbor freight I could buy? Any advice would be most appreciated. Also, will I encounter any issues or concerns by swapping the lens – leds or anything else?

Twist it with your hands. Is yours extra tight or something?

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YogibearAl
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To change the lens you only need to unscrew the front bezel. No need to remove the retaining ring. The retaining ring is removed from the inside of the head only to remove the driver or side switch on the C8F.

I have a pair of small needle nose pliers that I use to remove retaining rings. Usually they come right off if not glued on.

Do a search for reflowing LEDs for swapping LEDs from the MPCB, or how to replace with new LEDs that are prebuilt onto MCPCBs if you want to change LEDs. You should be somewhat comfortable with soldering.

BTW, what lense are you trying to replace the factory one with?

Phoneas
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JasonWW wrote:
Phoneas wrote:
Pretty simply question for those experienced at tearing down lights – I want to swap out the lens on my C8F – if I don’t have any tools specific to flashlight modding, is there any tool in the typical household tool box that I can use without damaging the light and retaining ring? I was thinking locking pliers wrapped with electrical tape on the teeth with just enough pressure to get a grip to twist without denting or crushing it. This doesn’t sound like a good idea. Perhaps there is a tool at harbor freight I could buy? Any advice would be most appreciated. Also, will I encounter any issues or concerns by swapping the lens – leds or anything else?
Twist it with your hands. Is yours extra tight or something?

Mine is extra tight. Even tried a jar gripper. I was thinking it would just spin off, but since it wasn’t I was thinking maybe I am missing something and/or have gotten in over my head.

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YogibearAl wrote:
To change the lens you only need to unscrew the front bezel. No need to remove the retaining ring. The retaining ring is removed from the inside of the head only to remove the driver or side switch on the C8F.

I have a pair of small needle nose pliers that I use to remove retaining rings. Usually they come right off if not glued on.

Do a search for reflowing LEDs for swapping LEDs from the MPCB, or how to replace with new LEDs that are prebuilt onto MCPCBs if you want to change LEDs. You should be somewhat comfortable with soldering.

BTW, what lense are you trying to replace the factory one with?

I am looking at replacing it with the yellow one in this bunch. https://www.ebay.com/itm/Set-of-4-42mm-diameter-Lens-for-C8-Flashlight-B... – the link is not spam. It is an eBay seller.

I get a bit of dense fog where I live and driving snow think star field effect – like driving along in your car in heavy snow at night) – in either case, a white led is not helpful. I tried a 2700k from Sofirn (IF25) and it was mildly better. So I thought I would swap out the clear lens for the yellow one and see if it improves visibility under either condition and if it does post pics here – to the extent it is something people would be interested in. So the goal is just to simply swap the lens – nothing else at this point. Thanks!

YogibearAl
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Phoneas wrote:

I am looking at replacing it with the yellow one in this bunch. https://www.ebay.com/itm/Set-of-4-42mm-diameter-Lens-for-C8-Flashlight-B... – the link is not spam. It is an eBay seller.

I get a bit of dense fog where I live and driving snow think star field effect – like driving along in your car in heavy snow at night) – in either case, a white led is not helpful. I tried a 2700k from Sofirn (IF25) and it was mildly better. So I thought I would swap out the clear lens for the yellow one and see if it improves visibility under either condition and if it does post pics here – to the extent it is something people would be interested in. So the goal is just to simply swap the lens – nothing else at this point. Thanks!

Ah OK, Yeah there isn’t much heat at the lens, so may want to try something like they use for car fog light film, that will provide a better yellow filter. In your case you will just need to unscrew the bezel. Nothing else. Not sure why yours is so tight. I’d think a high CRI version of C8F 2700 along with a yellow lamin-X film would help?

Shows how the bezel comes off it is pretty tight. Took me a bit to get it off to take this photo.

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YogibearAl wrote:
Phoneas wrote:

I am looking at replacing it with the yellow one in this bunch. https://www.ebay.com/itm/Set-of-4-42mm-diameter-Lens-for-C8-Flashlight-B... – the link is not spam. It is an eBay seller.

I get a bit of dense fog where I live and driving snow think star field effect – like driving along in your car in heavy snow at night) – in either case, a white led is not helpful. I tried a 2700k from Sofirn (IF25) and it was mildly better. So I thought I would swap out the clear lens for the yellow one and see if it improves visibility under either condition and if it does post pics here – to the extent it is something people would be interested in. So the goal is just to simply swap the lens – nothing else at this point. Thanks!

Ah OK, Yeah there isn’t much heat at the lens, so may want to try something like they use for car fog light film, that will provide a better yellow filter. In your case you will just need to unscrew the bezel. Nothing else. Not sure why yours is so tight. I’d think a high CRI version of C8F 2700 along with a yellow lamin-X film would help?

Shows how the bezel comes off it is pretty tight. Took me a bit to get it off to take this photo.

!https://live.staticflickr.com/65535/49451487641_22907c1b12_z.jpg!

Thank you for the information and especially the picture. I am going to try the lens and see how that works out. I have a C8F with the three XPL LEDs 5500k and then I also ordered a C8F with lh351d-2700k. I was going to compare the two with the lens swap. I didn’t know if I could use the fog light film safely – so I will track some down to try that next. Thanks again for the help and picture!!

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Phoneas wrote:
JasonWW wrote:
Phoneas wrote:
Pretty simply question for those experienced at tearing down lights – I want to swap out the lens on my C8F – if I don’t have any tools specific to flashlight modding, is there any tool in the typical household tool box that I can use without damaging the light and retaining ring? I was thinking locking pliers wrapped with electrical tape on the teeth with just enough pressure to get a grip to twist without denting or crushing it. This doesn’t sound like a good idea. Perhaps there is a tool at harbor freight I could buy? Any advice would be most appreciated. Also, will I encounter any issues or concerns by swapping the lens – leds or anything else?
Twist it with your hands. Is yours extra tight or something?

Mine is extra tight. Even tried a jar gripper. I was thinking it would just spin off, but since it wasn’t I was thinking maybe I am missing something and/or have gotten in over my head.


The best thing to have for unscrewing bezels is a set of rubber strap wrenches like these.

They are $5 a set at Harbor Freight. Your local hardware store my carry a cheap set as well. You set them up in opposite directions and you get a lot more leverage.

Texas Ace Lumen Tube and JoshK Sphere calibrated with Maukka lights

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mortuus
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It it confirmed later batches of this light gives more lumen? i have one from banggood bought in May last year and its no way close to the stated 3500 lumens.. now also not long ago the spring bypassed wire fell off from the tailcap.. really bad job on that one… my l6 bypassed still havent come off….

but for a budget price this light is ok robust and not much to complain about really..

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mortuus wrote:
Is it confirmed later batches of this light gives more lumen?

No, based on reports from users they still seem to vary a bit.

I think the only people complaining about it not meeting specs are the few who can actually measure it. Most users only care if it’s really bright or not.

I wonder if they would sell less units if it were labeled 2500lm or 2750lm or 3000lm?

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Yeap possibly may sell better if they just call it a 2500lm and all will be fine. Still a great flashlight IMO and worth the $27 I paid for it. I am in the process of a complete tear down and rebuild with new wires spring bypass (maybe even on the tail cap with double spring), better thermal paste, etc… to see if I can get 3000lm or higher. Smile

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I think they just like most other chinese budget brands just do an estimated guess on the lumens… and if its a bit more then what u actual get it helps sales hehe..

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