Review: Sofirn C8F XPL (Pic Heavy)

NOTE: The top right picture is the first version of the C8F to show main exterior difference of switch placement.

This is Sofirn's second version of it's C8F triple-emitter light. The first version had a couple design flaws that have been completely corrected in this version. Not only that, this version has several big improvements that make it the high-end light that it was meant to be. It's a high performance general purpose light that is close to being suitable for usage by the general public. There is one item that one should consider when giving this light to a non-flasholic. (See Warnings section below).

I received this light steeply discounted from Sofirn to review. Sofirn has not tried to influence my report and I strive to be unbiased in my review). The kit I received included the a protected cell and battery charger. My review of the first version is here.

Pros:

  • Good looking light with very nice flat black finish
  • Useful general purpose beam profile with large hot spot and wide spill
  • Well-executed machining with square-cut threads. Arrived properly lubricated
  • Attractive reflector and lens
    • Really like how the emitters are oriented
  • No thread locker (aka "glue")
  • Excellent firmware ("FW") with 4 different User Interface ("UI") options
  • Nice mode separation, but a lower Low Mode would make it better.
  • Well-machined, thick Retainer rings for both the Driver and Tail Switch
  • Tail stands
    • Has two adjacent passages to prevent lanyard from interfering with tail standing
  • Spring electrical by-passes
  • 3000mAh protected cell that delivers 8.8 amps at startup without tripping (measured 2800mAh at 500mA on Lii-500, 10mR)
  • No detectable PWM or whining sounds

Cons:

  • Does not automatically step down from Turbo Mode when Turbo Mode is entered into directly from Off Mode.
  • Strobe modes are awkward to enter and change between.
    • EDIT: There appears to be no strobe mode per the manual. Maybe the weird strobe mode I encountered had something to do with my sample's ultimate failure.

Warnings:
First Warning:

Do not go into Turbo Mode directly from Off Mode unless you intend to monitor the light's heat and step down to the next level manually. The light will not step down automatically when Turbo Mode is switched to from the Off Mode. It will step down automatically if you switch to Turbo Mode from one of the On Modes. I ruined my light because I was not aware of this feature. After the incident this is how the light behaves:

  • Turns to On mode automatically when a cell is put in the light.
  • Can not be switched to Off mode
  • Can not switch between the Mode Sets
    • Stuck in the first Mode Set
  • It can switch between Modes within the first mode set
  • It can switch into and out of Turbo mode
  • Repeated attempts are sometimes necessary to switching modes.
    • I will try to swap out the switch to see if the switch is the problem

So the is still usable, I just have to turn it On and Off by a slight twist of the tail cap. Unfortunately, I no longer have Moonlight Mode or the other Mode sets and special features. I cannot find an obvious cause for the failure. I have asked Sofirn for their thoughts the matter. I'll report what I find out.

EDIT: Apparently, I misunderstood Tracy. There is no Turbo step down bug. Solfirn has tried to replicate the problem I had, but has not happened. It appears that my sample had some type of defect. It seems to be isolated as no one else has reported the same problem.

EDIT2: Sofirn provided me a replacement light. The replacement turns off at 2.5 minutes when it is put into Turbo Mode from Off Mode. It appears my first sample's problem is isolated as I have not heard of anyone else having this problem.

Second Warning:

This light should be a relatively safe light for non-flashaholics. That being said, no light can be 100% safe. There is always going to be someone or situation that create a potential hazard. For instance there is a muggles/kid mode set that only has the lowest 3 modes. One has to press the side switch for 10 seconds to enter or exit it. Some kids may figure this out. So the light should not be left with them unattended.

Cell:
Protected cell rated for 3000mAh's. Measured 2801mAh at .5amp discharge rate on Lii-500 (this was after the over heating incident mentioned in the "Warning" section below. Resistance measured 10mR. Don't know at what current it trips. It had no problem delivering 8.8 amps in Turbo Mode.

Charger:
Terminates at 4.15V. Have not tested for proper charging algorithm.

Output:
With the supplied cell, I measured 8.8 amps at the tail and 3000 lumens at startup in Turbo mode using the Sofirn provided battery. I'm not detecting any thermal sag. The light warms up nicely from head to tail due to well designed thermal path throughout the light. Lumens measured at 2900 at 30 seconds. My light tube should be ball park accurate, but even if my readings are a bit high (I don't think they are), the spec'd lumens rating is conservative.

My measurement for the first Mode Set were way different than the manually specified. You can tell in my beam shots below too. I measured 95, 1060K, and 2K in L, M, H modes. The manual specified 85, 650,1330 lumens. So Medium is a bit high and High is really close to Turbo. Not really a problem though because the other Mode Set options have some real nice mode separation options that are similar to what the manual specifies.

Driver and Testing Results:

This is a combination linear/Direct Drive ("DD") type driver. It has one AMC7135 for the low modes Current measured to the emitters is the same as current measured at the tail, both when in modes that use the 7135 chip and modes that use the mosfet (DD mode). Below is a chart showing what current was measured in the various modes of the first Mode Set at various voltages:


Could not detect and PWM (visually or with phone camera). Also could not hear any whining. Warning flashes occurred at 2.7x volts when in low mode. Not sure if it does that in the other modes. Light shuts off completely a 2 volts (but protected cell would probably shut off at a higher voltage first).

UI:
The UI is great. There are several mode sets to choose from. Just 4 clicks from any mode to go to the next mode set. There is even a muggles/kids mod set that only has the 3 lowest modes. The muggles mode requires a continuous press of 10 seconds to activate and to deactivate.

Some Tear Down Shots:

Arrived in big box from Amazon fulfillment. The product box provides good protection of the contents.

__________________________________________________________________________________

Build is beefier that the first version. Fins are thicker and not cut as deep. Gives a nice thermal path to move the heat all the way down the light.

Thermal paste looks good. Even afer the light has been used for a couple weeks and disassembled, it is still thin enough to squeeze out under pressure. I didn't reflow the emitters to test for DTP on the copper emitter base, but there is no sign of thermal sag in output tests. So it's safe to assume that it is DTP. EDIT: I just realized I could have just taken DMM probes to the solder on the the side of the emitters without having to reflow to test for continuity. I'll test next time I open the light, but I'm certain it will be DTP.

Reflow on all three emitters could have been better, but probably would not change performance measurably. IIRC from some of djozz's testing.

First shot below kind of gives a sense of how thick the wall of the head are. Both driver and tail springs are bypassed. Gauge is on the thin side. Nice retaining rings. Start easy and are thick enough to do the job properly.

Square-cut threads also on the top end of the battery tube. Emitter leads are desent thickness. Guessing 20 maybe 22 gauge. Tail cap threads were properly lubed.

The Switch PCB, Driver PCB, and Emitter MCPCB are 12mm, 17mm, and 30mm, respectively. I don't think the switch LED's on mine are wired. The switch cover looks black in the pic, but it is actually more a transparent smokey color. The switch cover well is 12.8 - 13mm in diameter. The cover is 14mm total diameter with button being 10.8mm. So 1.6mm lip. Inner diameter of the retaining ring is 10.7mm. Kudos to Sofirn for not anodizing the ring black. It wasn't hard to unscrew, but I didn't have to worry about scratching it like with the Q8 retaining ring. The cover is pretty short. Only 3.9mm tall. Of which, 1mm is the lip. Top of the cover is barely proud of the top of the retaining ring. This helps reduce risk of accidental activation, but is still comfortable to operate.

Beam Shots

Control, Low, Medium, High, Turbo modes:

Another part of driveway and a long distance shot (Both in Turbo):

Low, Medium, High, Turbo (Control would be just black like above):

Conclusion:

This light rocks. It really lights up an area nicely with it's beam pattern. I absolutely love the appearance, design, machining, finish, neutral tint and the beam pattern. The beam pattern is an excellent balance of flood and throw. I also like the UI a good bit. The Low Mode would be nice. It's a winner all the way around for what it is intended to be.

Sofirn asked if I would post a discount code for them. I see no issue with doing so as I don't get any compensation on any sales they may get from it. The code N6LKSTK9 will provide a 25% discount on the new version of the light. I just did a search on Amazon for the light and here is a link:

https://www.amazon.com/Sofirn-Flashlight-Resistant-Camping-Rechargeable/dp/B0778FLG6P/ref=sr_1_1?ie=UTF8&qid=1512327082&sr=8-1&keywords=c8f

Nice to the point review!

What size is the driver?

Sofirn asked me if I would post a discount code for them. I see no issue with doing so as I don't get any compensation on any sales they may get from it. The code N6LKSTK9 will provide a 25% discount on the new version of the light. I just did a search on Amazon for the light and here is a link:

https://www.amazon.com/Sofirn-Flashlight-Resistant-Camping-Rechargeable/dp/B0778FLG6P/ref=sr_1_1?ie=UTF8&qid=1512327082&sr=8-1&keywords=c8f

Ha! I'm such an idiot. I didn't think to measure that or the MCPCB. I'll get those at some point today. Thank you for the complement.

Thanks for the review.

Too bad for the turbo from off bug… should be easy to correct in the driver?

Thanks for the code, ordered one! :+1:

Thanks ImA4Wheelr. Nice review. Does the torch overheat and become damaged if switched directly on to turbo or does it just get very hot?

Too late! :smiley: Pretty nice price :wink: and I’ll have it by Wednesday! :open_mouth:

I would think so too. Based on my short experiences with Sofirn. They will respond with a fix.

It's fine when switched to Turbo while in any of the On modes. It steps down at 2.5 minutes. It's not uncomfortable to pick up if it was at room temperature to start with. The problem is if you go into Turbo from the Off Mode. It will not step down and if you leave it tail standing like I did, it will eventually get so hot that something in it seems to fail. I couldn't handle the light with bare hands by the time I realized the light had not stepped down.

Great review, exciting flashlight.
The Amazon listing says it has a Moonlight mode, what is the lumen rating in that mode?

Thanks!
Keith

I really liked the moonlight on this light. You hold the switch down for about 1 second to get to it. First the light turns off and then a spit second later moonlight turns on. It doesn't sound convient in words, but it is and is very natural feeling to either turn off the light or to go into moon light mode.

The manual says 1 lumen. That seems about right to me. I don't clearly recall what my light tube measured. I think it said zero.

Hope you like it as much as I did mine. Please make sure to read the Warning section in the OP.

Thank you for the question. I reopened the light and realized I need to put "No Glue" as a Pro.

The Switch PCB, Driver PCB, and Emitter MCPCB are 12mm, 17mm, and 30mm, respectively. I don't think the switch LED's on mine are wired. If they were, I don't think they would work because one LED looks like it might be on the PCB backwards. Can't really tell as the traces are hidden under the switch. The switch cover looks black in the pic, but it is actually more a transparent smokey color.

EDIT: I just compared the top of the switch PCB to the top of the Q8 switch PCB. They look identical. The Q8 has the LED's oriented in opposing directions too. So the LED's are likely oriented correctly.

That flashlight is shouting for a good FET+1x7135 driver with Narsil to make that switch light usable maybe a convoy L6 clear side switch fits. :slight_smile:
How much is the rubber button and the button lip diameter?

I'm measuring 14mm total diameter with button being 10.8mm. So 1.6mm lip. Inner diameter of the retaining ring is 10.7mm. Cudos to Sofirn for not anodizing the ring black. It wasn't hard to unscrew, but I didn't have to worry about scratching it like with the Q8 rings. The cover is pretty short. Only 3.9mm tall. Of which, 1mm is the lip. Top of the cover is barely proud of the top of the retaining ring.

I think I will Ask them to send a C8F host with MCPCB and switch board without driver and leds. So I can build it with XP-L HI or XP-L2 leds and a FET+1 driver with narsil. Thanx for measuring. I have 5 clear L6 side buttons at home. Do you have an L6 to compare them? Or if not I will measure mines at home in the morning.

Would like to see this light sold without the battery and charger for less money for those of us who are swimming in batteries and ample chargers but do understand that they do not want newbies to be beetching of low output, etc because they are using crap batteries.

Probably should just order the thing and be done with it. :slight_smile:
Later,

Keith

Nice tear down review. Thank you.
great potential for mods.

Bought one using code.

I don't have an L6. I've slowed down on light acquisition some time ago in the interest of marital bliss. Sure love the look of those L6's though.

I think you may also want to ask Sofirn if they can leave out the charger, cell, and usb cable. I think they intended to make this light safer for normal folk by using high Vf emitters (XPL), protected cell, Turbo step down, and a Muggle Mode Set offering.

No problem. I will measure it tomorrow.
You can buy them without battery and charger at Aliexpress Sofirn store