Sofirn C8F host. 21700 C8F Available

It looks like strain relief for the joints.

The replacement drivers do not have that red covering.

Kawi, your brite work a little bit back is stunning! Excellent work man! Really slicks up the all black light, for sure….

Thanks Dale! :wink: Got bored during a 24hr machine endurance run and the shop lathe was in the isle next to it. Didn’t notice the plant manager was standing behind me, he’s like a Ninja, scared the hell out of me, when I heard somebody say behind me…wow that’s beautiful… I jumped he jumped :open_mouth: He’s cool, borrows lights from me all the time, needs to buy a couple the money he makes…… :money_mouth_face: I let him borrow it the weekend before opening day, he brought it back, this is way too much light for me, got anything smaller? He loved the MH20GT… sent him a link and code, he can get his own. :smiley:

Agree, that C8F 21700 treatment is awesome! I got 351D 4000K 90 CRI's is my first 21700 host, just ordered a 2nd host. Really like how the XPL HI V2 5D's look in a triple, probably will do them in the next. Ohh - just noticed Richard is low on them - order 6 of last 8 just now...

I doubt the problem was the original FET.

According to the markings (2D030L) the old one is the NXP PSMN2R0-30YLD, which has a Rdson of about 2mOhm. That’s already really low. No way changing that to any other FET could gain 2 Amps, except the 2D030L

- is fake,

- is defect or

  • was soldered badly.

But I assume you found the real flaw with the retaining ring. And I lift my hat for that, because that would be a design flaw that’s very easy to overlook.

My fix would be to file down the lower part of the threading of the retaining ring in a 45° angle, so that enough threading is left but the ring can sit lower. That should give good contact.

Hey Tom, nice to see you… hope everything’s been all right… been a while!

I have a C8F v2 host I ordered right when they first became available. I haven’t managed to finish building a light with it, but I check the driver I plan to use with it for fit. The PCB is one of the Oshpark 2oz copper boards, which are really thin (0.8mm). The retaining ring clamps down nice and tight.

So, bad driver/ring fitment may be a problem for some lights, but not all of them.

Regarding the “filing down the lower part of the threading of the retaining ring” — may I request a photo or illustration of which part should be done? Sorry, I’m not really into modding and have not-so-good skills but would like to see if that can help the relatively low amps on the C8F 21700. Thank you.

I just got 1 today and it still has the red stuff on it. I have a 2nd one on the way, maybe it will be different.

I guess it varies. My replacement also had different color switch wires.

Both my hosts have different wire colors they must just use random wires. The red stuff is surely just to make the switch connection more durable.

See the green line.

If the drawing (from the first post of this thread) really resembles the C8F, then you can take away some of the threading. Just make sure you have

- enough threading on the retaining ring left to hold the ring under pressure and

  • enough space on the lower side of the ring to fit on the bare copper on the driver.

.

.

Pretty sure he means this (Pic courtesy of ImA4Wheelr). This would be the “underside” of the ring, notice, no holes for pliers cause it’s upside down.

No, pretty sure he doesn’t :smiley:

What I mean is filing the threading of the retaining ring.
Underside, yes, but from the outside, to remove some threading so you can turn the ring a bit more.

Your picture, contactcr, shows filing down the inside of the retaining ring. You do that when the ring collides with parts on the spring side of the driver. This wouldn’t be the case here with the C8F.

Wouldn’t it be easier to just put a few solder blobs on the outside of the driver? I built mine with a 1.2mm thick 20mm FET+1 and had no issue but I guess YMMV. The ring is ridiculously thick so i’ll leave up the pic even though it isn’t what you meant.

I did file down a little of the lower threads, but it had no effect on where the ring stopped rotating. Very strange. I may have to look at it closer.

Unfortunately I don’t have the 21700-C8F yet, so I can’t check myself.

I did this kind of filing several times with brass-pills (before the pill-less design took over) and it worked well to get the pill in deeper.

Of course you can do a comfy-style solder addon to the driver. Preferably the component side, as solder does not hold pressure well, especially not with a shearing force like from a retaining ring.

Btw, comfychair used a drill press to ‘mill’ these solder blobs flat. That was a classic.

Hey Sofirn next let give us C8F 26650 and the single emitter throwy version either 21700/26650 .

Why do you want 26650 when 21700 has almost the same performance but more compact?