The C8 that thinks it's a SRK

Flashlight Modding and DIY Parts
1

Get a cheap C8 with a nasty XRE in it, discard all the guts.

Cut off the driver compartment on the back of the pill & machine a new counterbore to fit the 17mm driver, cut out the flat base of the XRE reflector, make a centering ring/spacer out of scrap plastic, pick up some 18350s (hopefully better ones than the ones I got stuck with), add a MTG2 and a dash of copper, mix well.

Pill needs to be shortened to fit (barely) the two 18350s, also needs attention in the tailcap to gain as much space as possible:

Plain Nanjg 105c with a 150 ohm resistor & 4.6v zener diode added to keep the MCU alive at the new higher voltage:

Moonlight mode (using Nlite firmware; mode order is high-mid-low-moonlight, no memory, always starts on high mode):

These are probably the worst 18350s on the planet. Runtime is around 15-20 minutes before the weaker cell's low voltage protection kicks in and the whole thing comes to a screeching halt. And if I use more than 10 7135s, the overcurrent protection trips. Right now it's only using 8 350mA chips (only 2.82A at the tail), with better cells and 3 more 7135s it would be neck and neck with this very good SRK from FF/CNQG using XML T6 3C (5000k).

mouseover for the SRK: (they are aimed at slightly different spots, sorry 'bout that :( )

2

Very cool mod. And a very cool spot for flooder shots. Pls tell me that’s ur backyard. :slight_smile:

3

You are an artist. Love the custom reflector insulator.

4

Awesome mod, that looks like a very fun light!
Do you think it would be worth adding a 18650 extension tube, or gets the light after the 20mins to warm anyway?

5

It'll run fine from 18650s, no problem there but that kinda takes the fun out of it. If it's gonna be that long, might as well have a bigger head & reflector...

Heat isn't too bad. It's something like 17 watts not counting driver losses, the C8 seems to handle it a lot better than the P60 did.

6

now thats a sleeper...

very cool mod

7

I like that mod, I like it alot, do you ever leave the workshop other than for beamshots? :bigsmile:

8

Just took my C8 in my hand - having that output in this form factor just has to be fun, can’t argue with that. :wink:

9

Awesome mod! I think thats the amount of time most people use their flashlights anyways, so who’s counting on runtime :wink: Maybe you should try an aspheric with a MT-G2 next, the Z5 has two 18650s and is pretty cheap :slight_smile:

10

Great mod, C8s are classy & classic!
Where did you find the insulation gasket for the MT-G2?

11

Bravo! Very very cool! ‘Sleeper’ indeed!

I’ve got a couple of 16340 (more like 17360) Solarforce V2 880mAh that could probably kick sand in the face of those TFs!

12

Very cool. Now that’s a c8 my brothers going to want.

13

Check this out. Is the C8 brighter, or is it just a trick because of the different beam pattern?

Sure it's a larger spot, but looks like it might be more light in total...

And the SRK really is using 3C/5000k neutral XMLs, the MTG2 makes it look nearly purple.

14

Sweet.

15

It used to be a fan bracket/housing in an old HP or Compaq mid tower, don't know what flavor plastic it is but it's wonderful to work with. Cuts clean, doesn't clog up files or smear, can be heated for forming without turning brittle and crispy. I wish I knew what it was so I could buy more of the same stuff in sheets of various thickness.

16

So an almost-off-the-shelf ’7135 can drive an MT-G2… priceless.

In which part of the circuit did you insert the capacitor and the diode?
Would 2 fully-loaded Li-Ion (8.4V) be ok for the driver, after the mod?

This is awesome !

17

That’s a nice, even beam. Much more useful imo for most tasks.

So it is your front yard then!

18

Resistor in the range of 100-250 ohms replaces the polarity protection diode (at the LED+ pad), zener goes from MCU pin #8 to GND. Rating on the zener just has to be less than 6v, and more than 3v (or else MCU will trigger a low voltage warning & step-down). On this one I put the zener on the inside side of the driver because of lack of space on the other side with the 18350s, but if you have room it can go on the other side across the ceramic capacitor and do the same thing.

The zener bleeds off any voltage above its rating, so a 4.6v zener will maintain 4.6v in the power feed to the MCU. The resistor limits the current that can flow thru the zener to GND, while still providing more than enough current to run the MCU.

19

Ah, sorry, resistor, not cap. Getting tired.
Thanks a lot!

20

That C8 really does look brighter now! Who needs to buy a SRK anymore :slight_smile: Cant wait for you to put them in the J-19 and post images!!! :smiley: