Sofirn C8F host. 21700 C8F Available

Hi, great light!
Are there any plans for 21700, side switch, single led setup?

I tried to convince them but no answer.

Except for the side switch “Nightwatch EC21” is just that

The side switch what he wanted first place. Except for the side switch there are thousands of options with tail clicky single led flashlights.

There are also things like the MiniGT, etc which have side switches. It’s more rare to find 21700 tubes.

That is true. But if somebody want modding the mini GT driver is glued and special. in a sofirn you can build what you want so I will keep pushing that idea to them :wink:

I just got my C8F host in from Mountain Electronics, man this is a great looking light :heart_eyes:

I have a question for y’all though. This is my first time installing a driver into a light with a side switch, so I’m wondering where the leads get connected for the side switch. Reading around I think this is correct.


Under the green circle it says “OTC,” but it didn’t come with that resistor. Is this the correct place for the e-switch leads? I’ve read you can also connect the + to the MCU #2, and the - to any ground. But the OTC pads are supposedly better to use. I’m fairly confident that was what Richard was explaining over on his thread here: Comment #7944

Also, the driver didn’t come with any of the resistors under the yellow circle. I complicitly trust that Richard left them off for a reason. Just out of curiosity, what are they for?

R1 and R2 are typically the low voltage protection circuit. If you have Guppydrv or something like that which doesn’t use low voltage protection there’s no point in having those on there.

I usually solder one of the e-switch leads to pin 2 on the MCU. (The MCU is marked with a triangle or recessed dot at pin 1 , the board has an asterisk there, numbered 1-2-3-4 on the left in your picture, going around the clock to the other side is 5-6-7-8 with 8 being up on the inside) There is no “+” and “-” by the way, you’re just interrupting the circuit. The best ground (as if it mattered here, is the outer 3 legs of the FET, lot of space there anyway for a ground point, you could also use leg 4 of the MCU, or that OTC leg closest to the ground ring, just check for continuity with your multi-meter for ground.

FWIW, under the green circle OTC means Off Time Cap, the brown capacitor. Above it, the smaller black component is a resistor that is used to keep spikes down, this helps keep the light from flashing when entering the FET mode.

Dale, thank you so much for the info man! I was hoping to get this C8F together tonight, but I seem to be out of 20awg wire. 18 gauge fits, but 22 gauge is too big for the center hole on the driver. I definitely want the least amount of resistance on this powerhouse so I’m going to assemble it tomorrow when I get some 20 gauge. :+1:

Edit: Reverse the 18/22 gauge wires and it’ll make more sense :person_facepalming:

Don’t you mean 22AWG fits and 18AWG is too big?

Correct you are!

Sofirn has sent me two coupon codes:
18650 version C8F
20% off code: 20QSPTUA

SF14
20% off code: 2045TU4G

Yourrid, I just bore the center hole out a little on the driver to accept the 18ga. :wink: just make sure the via is staying intact so the MCU can get power from the spring on the battery side, that’s how it works after all.

Alternatively, you can strip and tin the end of your 18ga wire and solder it into the via, then do a more traditional spring bypass on the other side of the board. That will work as well. Even a 22ga spring bypass will work in conjunction with the gold plating on the spring, should net just about the same as if the 18ga wire were run straight through. Very short span we’re talking here, shouldn’t make a lot of difference.

Or use the 20ga wire Richard put on the driver for your spring bypass. :wink:

Or remove the driver spring and solder a brass button (copper button) on the driver for a direct contact to the positive terminal of the cell used. Be sure to have a good spring on the negative end in the tail cap with at least a 20ga bypass there. :wink:

Dale, I actually started out with a drill bit thinking I could just slightly enlarge the hole to get the 18ga through. The next size drill bit I have is the exact size of the gold circle around the center hole. 18ga would be ideal considering this is a FET, but I’m worried of making the hole too big, or nicking one of the chips.

The driver only came with 22ga wires which weren’t attached. I also bought a replacement driver for my Convoy L6 and it came with 22ga as well. I went around searching for 20ga wires today but had no such luck; Hobby Town USA, Fry’s, Microcenter, Walmart, hardware stores. No luck.

I’m looking online now to buy some 20ga (probably need to use it on the L6 driver as well anyways), along with some Kapton tape for under the C8F’s reflector as a precaution.

I made the same kapton tape safety to reflector wire pockets and used 20GA in the XP-L HI build and it puts out 3300 lumens. Stock C8F driver, Stock tailcap spring bypass.

ZozzV6, I saw those pockets in the reflector and thought “I better be spot on with my soldering, or its time to invest in Kapton tape.” :laughing:

I’m hoping this FET from Mtnelectronics, XP-L Hi’s, 20ga wires, double spring bypass and some Samsung 30Q’s puts out some serious light :smiley:

They made everything locate off of everything else, the slots for the wire contacts, the hole for the screw that holds the MCPCB and reflector together, it all key’s together nicely. Even clears 18ga (but yes, keep it neat)

Run the wire from the MCPCB and leave em both long, run em out the end of the head. After you put the screw inside the head to snug the reflector/mcpcb assembly into the top you can then cut off and strip the two leads for the driver. Just tin the stripped end of the positive and solder it into the via. Solder the black one onto the pad, solder the switch leads to the driver, then sort of twist the driver/wires assembly down into the hole so the wires lay down in there. Press the driver into position and hold the end of the spring while you start the retaining ring. I like to hold the driver down in place until the retaining ring bottoms out, then watch that you don’t spin the driver too much more while you snug the ring down. Voila! Il Monstro!

Edit: You can use a screwdriver or pair of tweezers to wedge into the spring at the driver so it spreads open enough for you to get your soldering iron inside the spring, solder the 18ga wire into the via from inside the spring on the spring side, that way you won’t contact any components. :wink:

I, personally, think that flashlight modders should have been gifted with two sets of arms/hands. :wink:

Edit: Your photo, enhanced…