Thanks Dale! 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 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.
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...
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.
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.
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.
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.