Sofirn C8F 21700 Teardown and Review

102 posts / 0 new
Last post
Funtastic
Offline
Last seen: 12 hours 54 min ago
Joined: 06/26/2014 - 02:14
Posts: 283
Location: New Zealand

Is lux the intensity of the hotspot/place of the beam being measured?

Okay, I always thought lux = lumens when calculated correctly.

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

Funtastic wrote:
Is lux the intensity of the hotspot/place of the beam being measured?

Okay, I always thought lux = lumens when calculated correctly.


Lux and lumens are completely different.

Lumens is the total amount of light regardless of beam shape.

Lux is the highest intensity at any one point in the beam and is only useful to determine how far the beam will travel.

You could have a 200 lumen light that was floody and only measure 80 meters or you could focus it really tightly and make it go 800 meters.

contactcr
Offline
Last seen: 3 hours 57 min ago
Joined: 05/19/2017 - 18:52
Posts: 2377
Location: US

if it was XML it’s just as likely he perceived it as more floody and looks more impressive at short distances or indoors. Either way it’s perceived brightness. You wont be able to really notice much difference between 2000 and 2700 except for the throw/beam shape.

On the “bright” side now he has a light suited for more flood and more throw, whichever they may be!

Funtastic
Offline
Last seen: 12 hours 54 min ago
Joined: 06/26/2014 - 02:14
Posts: 283
Location: New Zealand

I just sent him the Sofirn Q8 so I’m sure that’ll impress him at 5000 lumens with spring bypasses.

Thank you for both of your input answering my questions

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

I just tested my new batteries in the C8F (has new MOSFET and stock led wires). I measured both lumens (TA Lumen Tube calibrated with Maukka’s light) and tail amps (using UNI-T UT210E clamp meter and heavy wire) with the Samsung 30T, 50E and Sofirn 4000mah 21700.

Something funny happened as all my first round results were down in power by about 500 lumen and two amps (left side of chart). I checked the driver components and saw no issues, but around the driver edge and driver shelf there seemed to be some dirt or maybe flux build up. I cleaned it all up with a q-tip and alcohol then reassembled. This fixed it. So new readings are on the right hand side. I did not recharge the batteries between the first two 30 second pulls and the second two 30 second pulls. I took Turn On measurements as well as 20 seconds and 30 seconds to give an idea of how output was dropping.

All 3 cells did very well. I think the 30T did not have as much voltage sag which is why it had slightly higher lumens while drawing the same amps as the Sofirn battery. It goes to show how good the Sofirn battery is.

Since I like this light so much, I may swap in a Lexel driver in order to get that instant jump to Turbo (no more ramping up in output) and to know the battery voltage better. The stock driver does not start showing red until 3.0 volts.

Oh yeah, I charged each cell on my Miboxer C4-12 and tried to get a rough idea of their Internal Resistance. This charger is known for reading IR a bit high, but the results seemed fine.

SKV89
Offline
Last seen: 44 min 31 sec ago
Joined: 12/10/2017 - 12:46
Posts: 2796
Location: US

Did you buy another one or did you swap in the revised driver they sent you? Thanks for the very useful data!

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

SKV89 wrote:
Did you buy another one or did you swap in the revised driver they sent you? Thanks for the very useful data!

I only have the one light with the original driver. A few posts back I showed that I swapped the FET out for one with lower resistance.
Funtastic
Offline
Last seen: 12 hours 54 min ago
Joined: 06/26/2014 - 02:14
Posts: 283
Location: New Zealand

I read that Sofirn had confirmed it was the FET causing the reduced lumens, this can’t be the only cause looking at your results

Muto
Offline
Last seen: 7 hours 58 min ago
Joined: 09/04/2012 - 16:42
Posts: 1994
Location: Southeast, PA

I am not ragging on this new version but I just have 2 questions;
So only after these mods of replacing the FET and beefing up connections is this flashlight just now getting to the output I already have out of the box with the 18650 version when used with a good cell?

Just a newfangled 21700 battery capability.
Where’s the love?

Will wait for the factory BLF approved/vetted Hotrodded version.

After the Apocalypse there will be only 2 things left alive Cockroaches and Keith Richards
..
Friends don’t let friends use ATT/DirectTV
..

I used her, she used me
But neither one cared
We were gettin’ our share
“Bob Seger”

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

Funtastic wrote:
I read that Sofirn had confirmed it was the FET causing the reduced lumens, this can’t be the only cause looking at your results

The FET they used in the early drivers did have a little more resistance in it which reduced output. The details are in post #17

I actually don’t know what a triple xpl can do amperage wise. Right now each emitter is doing about 3.2A and about 1000 lumen.

Should we be expecting 15A and 4000 lumen?

Is there too much resistance in the led wires?

A completely new driver might tell us if there is something in the Sofirn driver that is creating a bottle neck.

Frankly, I was okay with the stock driver that only drew 7.25A and 2600 lumen. I tend to set it at about 500 lumen for walking around and do the occasional blast of turbo. It’s a big jump in output and it doesn’t get too hot or run the battery down too fast. It is a good general purpose light.

Using the 30T and 4000mah battery gets the light hot so fast it’s not that practical anymore. If I put a Lexel driver in it and got even more output, I’d probably remove the spring bypasses to try and reduce output on turbo to make the light practical again.

I know, it’s not the BLF way to reduce output, but I use this light at work where it needs to be a bit more practical.

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

Muto wrote:
I am not ragging on this new version but I just have 2 questions;
So only after these mods of replacing the FET and beefing up connections is this flashlight just now getting to the output I already have out of the box with the 18650 version when used with a good cell?

The latest versions already have the updated FET so you don’t need to do anything.

What do you mean by beefing up connections? Both springs are factory bypassed. There is nothing to do there either.

Do you mean replacing the led wires with bigger ones? How big are the wires in the 18650 version? Bigger or the same? I don’t know.

How many amps does the 18650 version pull? I don’t have one so I don’t know.

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

I looked up reviews for the 18650 xpl version to find amp draws. (This is usually more accurate than lumens)

Bilakos10 measured 8.33A with a Samsung 25R cell, but that is not a very good battery.

Robo819 measured 8.4A with the Sofirn 18650 and 8.9 with an LG HE4 cell.

ImA4Wheelr measured 8.8A with the Sofirn 18650.

Barkuti measured 9.7A with a Samsung 30Q. He used a shunt as apposed to a clamp meter.

DB Custom drew 13.57 amps with a very high drain VTC5A 2600mah and with slightly lesser batteries, like a 30Q, he got between 10A and 11A. This was with 18ga led wires and an upgraded MOSFET though. So it doesn’t really count as stock.

Since the 18650 version is supposed to be about 2500 lumen and the 21700 version is supposed to be 3500 lumen I’m guessing there is some kind of bottleneck with this 21700 driver. The 21700 light should probably be drawing at least 12A to 13A stock to get 3500 lumen. Sofirn may have over rated this 21700 version. It might be a true 3000 lumen light.

Muto
Offline
Last seen: 7 hours 58 min ago
Joined: 09/04/2012 - 16:42
Posts: 1994
Location: Southeast, PA

Referencing this post;
http://budgetlightforum.com/node/57806

Dale shows the following;

Sofirn …………………………..30Q………………………..Sony VTC4
1. 0.552 Lumens…………………0.552 Lumens………………0.587 Lumens
2. 37.50 Lumens…………………22.29 Lumens………………22.81 Lumens
3. 83.15 Lumens…………………..82.8 Lumens………………84.53 Lumens
4. 890 Lumens………………….872.85 Lumens………………931.5 Lumens
5. 1338.6 Lumens……………1314.45 Lumens…………….1400.7 Lumens
6. 3015.3 Lumens……………3018.75 Lumens…………….3125.7 Lumens
…..2756.66 at 30 sec…………….2691 at 30 sec

This is stock from what is described.
Amp draw do not know.

After 18 gauge wires and new mosfet went well over 4000

Bottom line, If I can’t see the difference I do not need to be buying a new battery form just to be “like the new kids”
Like the New Version just can not justify another version at this time.
Thanks!

Keith

After the Apocalypse there will be only 2 things left alive Cockroaches and Keith Richards
..
Friends don’t let friends use ATT/DirectTV
..

I used her, she used me
But neither one cared
We were gettin’ our share
“Bob Seger”

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

Muto wrote:
Referencing this post;
http://budgetlightforum.com/node/57806

Dale shows the following;

Sofirn …………………………..30Q………………………..Sony VTC4
1. 0.552 Lumens…………………0.552 Lumens………………0.587 Lumens
2. 37.50 Lumens…………………22.29 Lumens………………22.81 Lumens
3. 83.15 Lumens…………………..82.8 Lumens………………84.53 Lumens
4. 890 Lumens………………….872.85 Lumens………………931.5 Lumens
5. 1338.6 Lumens……………1314.45 Lumens…………….1400.7 Lumens
6. 3015.3 Lumens……………3018.75 Lumens…………….3125.7 Lumens
…..2756.66 at 30 sec…………….2691 at 30 sec

This is stock from what is described.
Amp draw do not know.

After 18 gauge wires and new mosfet went well over 4000

Bottom line, If I can’t see the difference I do not need to be buying a new battery form just to be “like the new kids”
Like the New Version just can not justify another version at this time.
Thanks!

Keith


His lumen tube reads way higher than mine. This is why I don’t use his lumen numbers. The amp draw is more accurate.

The best thing about the 21700 version is the new ramping mode UI with one click on/off. This is why I never bought the 18650 version.

Muto
Offline
Last seen: 7 hours 58 min ago
Joined: 09/04/2012 - 16:42
Posts: 1994
Location: Southeast, PA

JasonWW wrote:
Muto wrote:
Referencing this post;
http://budgetlightforum.com/node/57806

Dale shows the following;

Sofirn …………………………..30Q………………………..Sony VTC4
1. 0.552 Lumens…………………0.552 Lumens………………0.587 Lumens
2. 37.50 Lumens…………………22.29 Lumens………………22.81 Lumens
3. 83.15 Lumens…………………..82.8 Lumens………………84.53 Lumens
4. 890 Lumens………………….872.85 Lumens………………931.5 Lumens
5. 1338.6 Lumens……………1314.45 Lumens…………….1400.7 Lumens
6. 3015.3 Lumens……………3018.75 Lumens…………….3125.7 Lumens
…..2756.66 at 30 sec…………….2691 at 30 sec

This is stock from what is described.
Amp draw do not know.

After 18 gauge wires and new mosfet went well over 4000

Bottom line, If I can’t see the difference I do not need to be buying a new battery form just to be “like the new kids”
Like the New Version just can not justify another version at this time.
Thanks!

Keith


His lumen tube reads way higher than mine. This is why I don’t use his lumen numbers. The amp draw is more accurate.

The best thing about the 21700 version is the new ramping mode UI with one click on/off. This is why I never bought the 18650 version.

OK, that’s cool
Good info.

After the Apocalypse there will be only 2 things left alive Cockroaches and Keith Richards
..
Friends don’t let friends use ATT/DirectTV
..

I used her, she used me
But neither one cared
We were gettin’ our share
“Bob Seger”

SKV89
Offline
Last seen: 44 min 31 sec ago
Joined: 12/10/2017 - 12:46
Posts: 2796
Location: US

JasonWW wrote:

His lumen tube reads way higher than mine. This is why I don’t use his lumen numbers. The amp draw is more accurate.

The best thing about the 21700 version is the new ramping mode UI with one click on/off. This is why I never bought the 18650 version.

I just spent some time to dig up my post with my own lumen numbers and seems like Dale’s measurements are spot on

SKV89 wrote:
Received my C8F 21700. The size is just a tiny bit larger than the 18650 version. The finish is a tad bit shinier than the mat finish on the 18650 version. Tint is a little cooler than the 18650 version, but both are pretty decent. It comes with a sleeve to allow use of 18650. Both versions come with factory spring bypasses. The following are my test results from a TA Lumen Tube calibrated with Maukka calibration lights.

C8F 21700 on Samsung 21700 30T: 2,890 lumens at 1s
C8F 21700 on Sony 18650 VTC5D: 2,500 lumens at 1s
C8F 18650 on Sony 18650 VTC5D: 3,155 lumens at 1s

nkresho
nkresho's picture
Offline
Last seen: 5 hours 17 min ago
Joined: 11/26/2017 - 20:36
Posts: 227
Location: Pittsburgh, PA, USA

I grabbed a few 40T to try them out in my light.

I’ve got the SIRa800 and 18 gauge from the driver to mcpcb installed.

Turn on with sofirn battery gave me 3,904 and 3,504 at 30s
Turn on with 40T gave me 4,024 and 3,764 at 30s

3% difference, negligible IMHO

Both tests, batteries fresh off the charger. Measured in a maukka light calibrated sphere.

KawiBoy1428
KawiBoy1428's picture
Offline
Last seen: 7 hours 55 min ago
Joined: 04/11/2014 - 18:05
Posts: 3720
Location: The Motor City

Mtn. D4-v2 driver in mine, I got 3890lm on the Sofirn battery 4430-4400lm on 2 of my 30T batteries.

KB1428 “Live Life WOT

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

SKV89 wrote:
JasonWW wrote:

His lumen tube reads way higher than mine. This is why I don’t use his lumen numbers. The amp draw is more accurate.

I just spent some time to dig up my post with my own lumen numbers and seems like Dale’s measurements are spot on

This does not invalidate my statement. It still holds true.
JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

I’m guessing there is some kind of bottleneck with this 21700 driver.

The 18650 version light seems to be capable of higher output then the 21700 version which is the opposite of what it should be.

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

KawiBoy1428 wrote:
Mtn. D4-v2 driver in mine, I got 3890lm on the Sofirn battery 4430-4400lm on 2 of my 30T batteries.

Did you measure the stock driver output in lumens and tail amps?

How many tail amps are you drawing with the new driver?

I’m curious what effect a straight driver swap can do.

KawiBoy1428
KawiBoy1428's picture
Offline
Last seen: 7 hours 55 min ago
Joined: 04/11/2014 - 18:05
Posts: 3720
Location: The Motor City

JasonWW wrote:
KawiBoy1428 wrote:
Mtn. D4-v2 driver in mine, I got 3890lm on the Sofirn battery 4430-4400lm on 2 of my 30T batteries.

Did you measure the stock driver output in lumens and tail amps? Yep, that is how I seen the Turbo out put Creep..up…slowly.. 2400/2600lm Sofirn/30T 5.8-6.4amps IIRC

How many tail amps are you drawing with the new driver? Sofirn 13.6amp, 30T’s 14.8-15.02amps

I’m curious what effect a straight driver swap can do.


D4v2 driver with 20awg leads,18awg TC bypass 30T off the charger at 4.21v….4460lm. No doubt 18awg leads will get you a bit more… I don’t have the patience for it on this light. Big Smile

KB1428 “Live Life WOT

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

I think I figured out a small design flaw in the manufacturing that is causing reduced output.

It seems the new aluminum driver retaining ring is not able to fully tighten down on the driver (at least my driver). I thought it felt strange as it only tightened up to one point and then would go no further. I used some marker dots to confirm this. The ring seems to be squeezing the driver lightly instead of firmly.

The 2A difference I saw earlier with my battery tests and again a 1A difference after I swapped to 18 ga led wires. I can move the driver around when the retaining ring is about 1/16 of a turn from its “tightened” position.

So maybe the driver pcb is a bit thinner than it was supposed to be or maybe the threads are not cut far enough. Maybe they should have continued using a brass retaining ring. I’m not sure.

I will relay this information to Sofirn.

d_t_a
Online
Last seen: 14 min 27 sec ago
Joined: 08/04/2017 - 23:58
Posts: 1282
Location: Manila, Philippines

Thanks for the review and also the analysis on why the Sofirn C8F 21700 may sometimes be underperforming.. Hope Sofirn will solve the “underperforming” issue soon.

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

d_t_a wrote:
Thanks for the review and also the analysis on why the Sofirn C8F 21700 may sometimes be underperforming.. Hope Sofirn will solve the “underperforming” issue soon.

They already know the old FET is not the best, so it hurts performance a little. They have already switched to a better FET.

I don’t know if all the lights have a weak contact on the driver retaining ring. Some may.

I also recommended they swap the led wires to 18ga. It’s a cheap way for them to boost the output even higher.

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas

Here’s an update. I swapped out the factory wires (I think 22ga) with some heavier 18ga. I ended up shortening them about an inch, but that’s barely long enough. I recommend 1/2” shorter at most.

Once I got a decent connection with the driver retaining ring, output jumped up quite a bit. Look at the bottom of the page. I was in a rush so I only did Turn On and 15 seconds for both tail amps and lumens with each battery.

The Sofirn battery gained about 2 amps and 400 lumen. 3,450 lumen, wow!

The 30T battery gained about 1.5 amps and 300 lumen.

The 50E battery gained about 1.4 amps and 300 lumen.

The little Samsung 30Q gained about 1 amp and 300 lumen.

So some pretty nice gains just by swapping to 18ga wire. Beer

SKV89
Offline
Last seen: 44 min 31 sec ago
Joined: 12/10/2017 - 12:46
Posts: 2796
Location: US
JasonWW wrote:
SKV89 wrote:
JasonWW wrote:
His lumen tube reads way higher than mine. This is why I don’t use his lumen numbers. The amp draw is more accurate.
I just spent some time to dig up my post with my own lumen numbers and seems like Dale’s measurements are spot on
This does not invalidate my statement. It still holds true.

But I thought your lumen sphere is calibrated with Maukka lights so it should be reading about the same as mine. So if Dale’s measurements are similar to mine, then shouldn’t it be similar to yours?

SKV89
Offline
Last seen: 44 min 31 sec ago
Joined: 12/10/2017 - 12:46
Posts: 2796
Location: US

JasonWW wrote:

The Sofirn battery gained about 2 amps and 400 lumen. 3,450 lumen, wow!

The 30T battery gained about 1.5 amps and 300 lumen.

The 50E battery gained about 1.4 amps and 300 lumen.

The little Samsung 30Q gained about 1 amp and 300 lumen.

So some pretty nice gains just by swapping to 18ga wire. Beer

Very nice info. So the 30T measured 3,400 lumens, which is less than the Sofirn 4000mah because of bad connection? Also the performance of the Sofirn 4000mah is very impressive. Seems like a rewrapped Samsung 40T.

JasonWW
JasonWW's picture
Offline
Last seen: 57 min 11 sec ago
Joined: 10/22/2016 - 11:41
Posts: 11162
Location: Houston Texas
SKV89 wrote:
JasonWW wrote:
SKV89 wrote:
JasonWW wrote:
His lumen tube reads way higher than mine. This is why I don’t use his lumen numbers. The amp draw is more accurate.
I just spent some time to dig up my post with my own lumen numbers and seems like Dale’s measurements are spot on
This does not invalidate my statement. It still holds true.

But I thought your lumen sphere is calibrated with Maukka lights so it should be reading about the same as mine. So if Dale’s measurements are similar to mine, then shouldn’t it be similar to yours?


I don’t know why, but my lumen tube seems to read a bit lower than others. Not so much with other TA Tubes, but with some other different designed measuring tubes.

Like when it comes to the xhp70.2. Dale can measure lights with that emitter at 6000-7500 lumen.

With my L6 I can only get 5300 lumen at turn on. This is with 2 different color temp leds and Liitokala cells drawing 17.6A. Even with Aspire 4300 cells drawing 19.6A, I only see 5500 lumen at turn on.

Keep in mind that Dale does not use a TA lumen tube. He uses a lumen tube design with no diffusers and calibrated by a wide variety of factory lights. (Unless he has recently bought a Maukka calibrated light). I think he always uses turn on numbers and never anything lower.

So I always take his, and everyones, lumen results with a grain of salt. People should not take my lumen numbers as exact, but just in general.

I am really surprised your lumen numbers and Dale’s are really close. Have you compared the output of several factory or modded lights between him and you or just a few?

SKV89
Offline
Last seen: 44 min 31 sec ago
Joined: 12/10/2017 - 12:46
Posts: 2796
Location: US

Besides the C8F, I haven’t compared my numbers with any of his. I guess the diffuser on the TA tube evens out the beam for more accurate result whereas other lumen measuring devices might favor concentrated beams.

Pages