Sofirn C8 Quick Review

Thanks for all the in-depth info and pics! One thing I was wondering, does a Convoy C8 battery tube screw into the C8F head?

Thanks for your idea:

:slight_smile:

Nice! That looks pretty cool all mixed and matched! :slight_smile:

I have a few 9926A dual n-channel MOSFETs lying around, not yet unsoldered off broken powerbank PCBs. These:

Banggood is a bunch of @#$%, I have been forced to view the source code of the page to be able to access the image links. Makes hot linking their stuff pictures much harder, at least if you're using Chrome browser. JavaScript related crap.

Ranting aside, according to @#$% datasheet the 9926A MOSFET features… (edited all of this useless information). This means the combined dual channel resistance won't go much above 20ish mΩ even with a semi-drained cell on a hot flashlight.

Cheers

Originally posted on Fri, 10/06/2017 - 03:36; useless data fix.

User AnhTran has a little Nichia 219C 5000K R9050 sale going on, just saw his last message.

Cheers ^:)

By curiosity; how much amps/ watts does that stack solder add?

Thanks for the review. Tailcap/ switch, very good quality u-shaped tailcap and great switch

You’re most welcome Diego :slight_smile:

Jouna, setting up more 9926A MOSFETs in parallel reduces the overall RDS(ON) and increases continuous current handling accordingly for as long as the heat dissipation also improves proportionally, yet although this is not the case it is with regards to the instantaneous figures and for the continuous to some extent. With two 9926As stacked the driver should be handling 12 - 16A and optimizing the tail switch resistance and losses would be the next in line thing, imho.

Cheers

Whoa :slight_smile: I thought some improvement in output but not quite that much :slight_smile: Thanks though Barkuti :slight_smile: If and when you add that to your C8F do tell about results.

I'm smelling some sort of misunderstanding here, Jouna. Please bear in mind I said the driver should handle 12 - 16A with two 9926A chips (each chip holds two n-channel MOSFETs, thus stacking two means 4 MOSFETs), I say it just because the datasheet suggests up to 8A per chip (with a standard level of cooling we can't guarantee in such small flashlight driver PCB), not because I am predicting you'll get such a crazy amperage. If you're stacking the chips add some thermal paste over the roof of the ones below (and proper soldering, of course).

MOSFET stacking example:

AO4410 over Si4324DY units., drain terminals can be observed at the center. That little solder peak rubbing the peg is from a wire below the MOSFETs.

Cheers ^:)

P.S.: you may want to edit your previous message, I think it's missing a [/quote] thing, Jouna.

XXX-Man seems to be having current draw issues with his C8F. The triple emitter MCPCB is probably not adequate, no direct thermal path. Thermoelectric separation and/or thermoelectric separated (=DTP) copper boards these chinese folks like to say.

Cheers :-)

P.S.: leave those XP-G2s onboard for a while, kotobuki. ;-)

Thanks for your infos, I’m charging my Samsung 30Q. I will test with C8F ver “XP-G2” tomorrow.
Let’s pray :smiley:

Better? Yes, I did misunderstood. Thanks for your info Barkuti.

I am getting the C8T Jouna, mentioned it before. After witnessing this manufacturer C8F screw-up, looks like the single emitter versions have a much better chance to work right. I'll be checking out the emitter board and other details in my unit. Hope the XP-L HI comes mounted over a direct thermal path board, if not I won't be fully testing the flashlight until I can fix that. I'm serious.

Maybe the thing is already calling for an emitter swap.

Cheers :-)

Ok, sorry Barkuti. I’m thinking also change emitter from XP-L to XP-L HI emitter. I like throw :wink: With direct thermal path of course.

Took a peek over the ThorFire TA13 (aka Sofirn SF30) drivers I took out from two recently modified units. I can see the same 10-pin unknown microcontroller onboard, next to a 3-pin voltage regulator marked as “662K”. kotobuki, can you please comfirm the 3-pin thingie next to the 9926A boasts such 662K markings?

It is more or less obvious to me now what Tracy Wan (from Sofirn) meant when she said high and low power MOSFET: it's the 9926A, plain and simple, with both channels driven for maximum output and just one for a bit less rock n' roll.

Even cooler fact for those of you daring DD lovers is that the TA13 (Sofirn SF30) uses three small AO3400 MOSFETS (marked as A09T or whatever) each with a 200mΩ resistor in series! (edited) Clarification: the whole R200 stack is in parallel (66.67mΩ combined), and likewise are the AO3400s driven. The AO3400 is rated for up to 5.7A each and its resistance at a low VGS doesn't climbs much above 20mΩ; if you dare to bypass all of the R200s you may end up with a surprise. The stock XM-L2 may not survive, Texas Ace blew up one the newer ones at just ≈5.5A.

Take care.

Cheers :-)

Originally posted on Sat, 10/07/2017 - 14:23; clarification added.

It has no name on it! I did try to clean any residue but still can’t see any name on it.

By the way, my C8F version “XP-G2” with Samsung 30Q get hot quickly, I scared to keep it on high mode too long to test for step-down automatically.
So, I will use low drain current battery with it, may be Walmart 18650 (Westinghouse).
:person_facepalming:

$11 for a SST-40 + FET flashlight? Interesting. :slight_smile:

Stacking FETs (no, they are not “MOSFets” these days) is not, In my opinion, an avenue worth pursuing.

The one being talked about here looks like a very good one. Each of the two FETs inside has under 18 mOhm on resistance, and whilst each is rated at 8A continuous, data is provided to four times that.

So the original dual package should be quite happy to at least 16A continuous. Dissipating no more than 2.3 watts at that current. Dropping 0.144 volts maximum.Which if properly laid out on a footprint with lots of copper plane, is well within spec. (Case temperature de-rating allows about 65C at that power)

Nevermind these numbers, this dual FET package will have, datasheet, passing 16A, under 9 milliohms resistance. I would suggest looking elsewhere to improve the overall resistance in the current path before worrying about the FET.

All you get by stacking on another one is a (theoretical) halving of Rds on. From maybe 9 to 4.5 milli Ohms. Vanishing returns, and very little more thermal dissipation in a stacked configuration.

Then again, I confidently expect it will carry on working at much higher current levels and temperatures, except that it is off the published datasheet.