NiteCore EC4GTS thermistor mod


I have a NiteCore EC4GTS (XHP35 HD) and I just got XHP35 HI NW from kaidomain - so I’m going disassemble it to swap the LED. But one idea come to my mind - is there a way to change Temperature Control settings? Not in a software, but rather hardware. For example - You can mod AceBeam K40M driver with resistor mod - to “fool” the driver sensing resistors and make it push more Amps into the LED. Is it possible to mod the thermistor in this EC4GTS so that it allows higher temperatures? Something like stacking another one on existing one, so that the resistance is half the previous value and that would “tell” the driver that temperature is lower than actually?

I’m no electronic, so pardon me for basic non-technical terms (I’m also not native english). I am perfectly aware, that such mod will decrease LED life, but I want to push it to the limits and use turbo mode occasionally (still got like 20-30 other lights Ican use regularly, so this one can be seen as a “fun to build” thing :smiley: ).

yes u can, maybe adding a resistor seri or parallel to NTC

In theory, yes you could do that.

If they use an NTC, you would need to increase the resistance as it should read a lower value.
For that, you need to find the NTC and it’s value and put a matching resistor inline to the existing NTC.
If you up a resistor on top of it, it will read lower which would suggest a higher temperature to the light.

For the example of led4power’s driver, he is using a 100k NTC with a Beta of 4250K.
That thermistor has 100k Ohm @ 25°C. The beta means, it has a resistance of 22.2k at 60°C and 12.9k Ohm at 75°C
In that case, to fool the Light into thinking real 75°C is only 65°C, you would need to add a 10k resistor in series.
But please, check my calculations and if that fits for your light. Maybe they use a different NTC!

From an review, it looks like the NTC is on the MCPCB.

What you need is the value of the small resistor on the MCPCB.
After that, you put another resistor either into to thin black cable or you rotate the NTC on the pads and put the resistor there.

Hmm… Now it seems, that it would be easier - and even better - to just use a copper DTP PCB and make it fit the body - and just put some resistor instead of playing around with NTC (no TC - just 100% output flat - nice).
But - let’s assume that this NTC is 100k Ohm. What will happen if I put a 1M Ohm resistor instead? Will some error occur or driver malfunction happen (since it could read temperature of below absolute zero :D)?

No idea. That depends on their software

OK, I was looking for a NTC data on BLF and found something. One modder did a very fancy thing with his EC4S, he just put the stock NTC on the plastic part of driver or holder and bang - simply done, goes 100% all the time. That will be easiest and I could do it right away. Also found, that at least in XHP50 version LED PCB isn’t DTP… :frowning:

Quote “Copper board IS NOT DTP!! Also, the negative pad is connected to the thermal pad, and the trace doubles as a heat spreader. I used a dremel to grind through under the thermal pad exposing the Cu underneath (the body of this light is isolated from all circuitry, so no worries about shorting).”

Does anyone understand what exaclty does this “grinding through” means and what it does?

And it’s done

Kids, today daddy’s cookin’

I tried to solder NTC to wires and I managed to it once - but man, this think is TINY. Then it got broken and I decided to try to turn the flashlight on - and it worked fine without NTC. So I just isolated ends of the NTC wires and just put them back in the head (so yeap, almost infinite resistance is fine)

So one job got me:

- 25-35% better throw (based on my luxmeter - could have been better, but still…)

- 4000K instead of some shitty 6500K

- no TC, turbo is now 100% flat all the runtime

  • put some better termopaste, factory one looks like some cheap Fujik

Thank You for Your posts zeroflow! :slight_smile:

So you just left the 2 wires disconnected from each other—I just put a 50.2 in my XHP 50 version——I checked the copper board — I thought mine was DTP — definitely ground and pos were isolated from the copper board itself

I forgot to look closely on my PCB, so don’t know if it’s still non-DTP in EC4GTS.
Yeah, for now I just left two NTC wires “flying around”. When I’m done playing with a new toy I’m going to take it apart again and make something better. There is some improvement over EC4, which I also have - in EC4 You have to unscrew SS bezel with some tool, and now - 2 hands, just 3 seconds and You have a body in one hand and bezel with reflector in the other. And no glue etc - that’s a plus for NiteCore.

+1 for MCPCB mod to DTP
cooler LED more lumens

Maybe —- But 4000k 50.2 is much more appealing to me—- I did an interesting test on mode 4 with my Lumen Tube (home made) It started out at 980 lumens and 1 hr 30 min later still was making 930 lumens— it stayed above 960 for 25 min—

I’m thinking of starting a Thread on this topic — there has been talk about Turbo step down etc—I think some people would be surprised that many Turbo modes are in a constant ramp down—especially small cell lights

Can’t find this thread right now but - I’ve seen a review of some EC4 family member in which there was a runtime plot on both 4th and 5th (turbo mode) - turbo had a TC step down, while 4th mode remained stable. Seems like only turbo mode has TC.

Bringing this thread back from the dead. I’m not sure I’m following along how to do this.

I’d love to see someone do a successful emitter upgrade of the EC4GT / EC4GTS. The form factor of this light is terrific. But alas, Nitecore always went for cool tint emitters in this. Frankly, I think this light has a lot of modding potential.

It begs for a Nichia B35AR

Considering the reflector aperture, voltage (18650 x 2), and driver, would it be a straightforward LED mounted mcpcb swap?

The stock gasket will need modified and mcpcb would need replaced, and sourcing a 12V (AR) version of this emitter will be difficult, but well worth it IMO. Sourcing components will be the hardest part.

Thanks for the details. A bit much for my capabilities at this point… and paying someone to do it would probably exceed the cost of buying something superior, like a Noctigon DM11. But I’ll keep it in mind for the future.

I’ve never modded a light before so I don’t even know where to start looking but I’d be willing to try it if someone can help me figure out what parts to buy.