howto: Build a Nanjg-092

Go get some of these:

Flatten out the legs and re-bend them like so:

And when upside down, the legs will now touch the PCB.

Strip off everything not needed from any Nanjg 105C.

With solder wick, clean off all the old solder, make sure it's nice and smooth.

These are the ONLY contacts on the top that are relevant, everything else can be painted over/taped over/ignored, it won't be used again.

Nope, not gonna fit in a 17mm pill like that, no way... trim off the extra length on the legs, and round off that corner with your trusty diamond file. I've also covered everything with kapton tape, then cut away at the two spots needed for contact.

Hey, where'd the little capacitor go? :~

...oh, there it is! :p

Add a very small little dab of JB Weld, stick the FET in place, then solder the legs.

Positive wire attaches at the normal place, the negative wire now goes to the big tab on the back of the FET.

For the Nanjg's ATtiny13 MCU to control the FET properly, it MUST use firmware running the unsexy 9.4kHz PWM. ALL of the 9.4kHz firmwares have the potential to cause an audible whine in the upper-middle modes (though not on the 100% mode). The non-whiny 19kHz firmwares will not control the FET properly, it's a different animal from the 7135s we all know so well (maybe a little too well...).

On this one, I used a customized version of DrJones' luxdrv. The ramping mode has been deleted, PWM levels are 2, 16, 84, and 255, with the mode order reversed. It still has the strobe and battery monitor modes. Hex file here, along with a batch file to flash it with just a double-click. Also has the source (in .txt file) used to make the .hex in case you want to make any changes or just have a look at it.,84,16,2)/

Ha, thanks comfy, I was already looking for moderator007's post in your lengthy FET-thread, this is easy now and very well presented, how lazy can modding be?

Hmm, Ebay-seller is not shipping outside USA, so not that lazy...

Good stuff comfychair, thank you very much for taking the time for this write-up. :slight_smile:

Thanks for posting this! Very nice and clear photos.

If you don't want to grind the FET body, you can also mount it right-side-up. This is my preferred method because I am lazy and I don't want the LED- to be able to touch the top of the pill in those lights where I can push it all the way in.

STAR FW works as well if you want turbo timer, etc. Just change TCCR0A = 0x23 to TCCR0A = 0x21. This works in both normal and momentary versions. It doesn't have any strobe or ramping features though like luxdrv.

Here's a really bad cellphone picture that I took of my first one, which is obviously not very polished:

You can move it further inbound and still flash the driver if needed. I cut the legs shorter then bend them down until they are close to the required output pad then solder in place. This first one isn't quite where I place them now, but you can get the idea.


Any idea the power it pushes in 255?

Total brilliance!

At 255 it is very near what the cells will do hooked directly to the LED. Can't remember what the exact value is but the resistance of this MOSFET is very low. I've seen 6A+ to an XM-L2 from a 20R, 7.5A+ into a triple XP-G2, and 11A+ into an MT-G2, quickly falling to around 10A after 30 seconds.

Thanks Comfy, definitely some good work there! Now someone is gonna have to hold my hand through learning solder wick braid so I can clean up a board like that, man that is nice!

Nice, thanks. :beer:
P.S. What’s with the other side of the driver, we strip all AMC’s? Maybe Nanjg 101 would be better solution then (with a bit more squeezing)!

Yes, all 7135s are stripped. You can see that in the pic where he says, "hey where'd that little capacitor go?". He moved it to the opposite side of the board.

Ah yes, you are right, where are my eyes…

P.S. how about combining this mod with zener mod for 2s-3s MT-G2?

Wow, comfy that is a superb job. Very neat soldering.

On the original board the capacitor is attached to the PWM trace and ground. This is the same trace the leg of the FET attaches to. When you moved the cap to the inside you went to the power lead and ground, does that have the same result? Is the capacitor doing the same thing when hooked to these different places?

never mind, I see now that I had the wrong via. Upside down and backwards. :~

Newp! Find the MCU pin marked 'Vcc', follow it down and look for the through-hole right under the fork in the road...

...that goes over to the battery side, to the capacitor. Other end of the cap goes to ground.

The new spot I picked for it goes between the LED+ pad and ground.

Sirius, you can use it with 2S MT-G2. Don't try 3S MT-G2 (this isn't a buck driver).

Also, you need to remember that this will go near direct drive, so it isn't a good setup for those lights that you need or want to limit the current on due to heat or battery life concerns. This is a good solution for when you can or want to run at direct drive current levels. This is a good "hot rod" light driver.

Well, 40% (PWM=100) will limit a triple XPG2 to around 3A, sounds practical to me. :bigsmile:

Awesome guide Comfychair!!!

I’ll have to give this a shot.

Comfy and Richard love to kick ass and chew bubble gum, and they are all out of bubble gum. Thanks for the detailed write-up comfy!

Richard, I don't really have a need for this right now, but I assume this will be your next offering?

Of course. I have just been way too busy. Next week I have a week "off" and will be catching up on everything and posting all of the new "stuff".

Thanks CC and others. Very nice work.

The place the cap used to be located was on the VCC trace and now it’s on the +Vin trace. It does the same thing, either way? So what, exactly, does the cap do anyway?