LED melting in Nightwatch NSX4

I used the 26800 7000mah battery you can order as a pack with the light and a charger.

That's a serious burn. I'd suspect a poor reflow, or poor MCPCB mount. The amount of amps/heat can be tremendous from one of these, and there's 4, not just 1, and probably all on the same MCPCB. I've seen old XML's melt the solder they are reflowed on because the old aluminum MCPCB couldn't shed the heat quick enough.

Lately on mods I've seen solder splashes on the backside of MCPCB's, preventing a good flat surface bond to the shelf it sits on. Thermal grease can help, but not as effective when the 2 pieces of metal aren't flat with each other. There's all sorts of things that can go wrong, and do go wrong. It's all about quality, or lack thereof.

Of course it could just be a bad LED as well.

I got a couple NightWatch lights - the IRA, NI40 Stalker, and the NA40SE.

The more high powered lights I take apart, the more I realize how necessary it is to take them apart, inspect them, sand down surfaces, re-apply thermal grease. They typically don't take care of the details, which are much more important on these high amp lights everyone is making now.

Neal doesn’t have a good record for helping customer problems. I would give him a few days before starting chargeback

The battery should really not be the problem, from my point of view a quality problem in any case.

Thanks all for the input and insight.

I think this is what I’ll have to do. Not had the best luck with this light :frowning:

I’m in a similar boat regarding Neal, have received a bad flashlight and trying to get some customer service……alas from what I’ve read and personally experienced it’s more akin to customer disservice.

I’m trying other avenues soon, approaching Fireflies directly or starting to cause a social media pain in the ass otherwise it’s a PP claim and I assume I lose on the $$$ having to send this garbage back.

I’ll try to source the items I’m after then cease to do business with a few particular online dealers.

Every time someone posts a bad experience on BLF, the seller (Neil) loses hundreds of orders. It makes so much sense for them to take care of the faulty product BEFORE people post their experiences.

This. There’s no way the light was over-driving XHP50.2. So it has to be a heat issue, which means the reflow was bad or the MCPCB contact is bad somehow (warped, solder blobs, thermal paste issues, whatever).

I feel like the more we see these “as bright as possible, as cheap as possible” lights the more we’re going to see issues like this. If you’re shaving every penny to make razor-thin margins on something as cheap as possible, the finer details probably won’t get addressed. And the higher powered the light, the more of an issue that’s going to be.

Ouch! That thing’s toast. It looks like a bad reflow/poor thermal paste application or a poorly prepared shelf. I agree with TomE on inspecting new lights (that can be opened easily anyway-dont want to void the warranty. They have varying levels of QC unfortunately and attention to detail is an afterthought.

Unfortunaty it means doing a warranty exchange or refund. Good luck.

Another thing - dunno if it's my perception or not - don't those centering rings look like they are overlaying the LED? They appear to be too small and are pressing down on the LED PCB mount itself. That could be a lot of pressure if that's right. I've seen this done with the SBT90.2's as well, but those mounts are pretty robust - dunno about the XHP50.2's.

I guess that's how TIR optics work as well, but seems odd to me on this setup.

I also have this light using the 26800 battery. The battery has great capacity but not nearly the push that the Samsung 21700 30T has. I’ve run mine at max with both for a few minutes and the light really gets too hot to touch, let alone hold. Your light is different in that it uses an OP reflector and mine is smooth. The LED spacer rings look identical. If you have the skill levels. Strip it down, take pictures and see if you can find the reason. I suspect it’ll be no paste, poor reflow or crude between the LED board and self. Good luck.

As Tom mentioned, these are issues that you can expect if you make these relatively small lights with absurd output, like Nightwatch does all the time. In principle I’m really pleased with the design of the Nightwatch lights, the designers realised the power that they are running at,they are thermally well done. But it also requires very careful assembly, especially making sure that the reflow is done well with the solder pads fully covered with solder, and making sure that the ledboard and led shelf are very flat so that they match well with a thin layer of paste in between. And it is the assembly that I never trust (with any flashlight for that matter) so the first thing I do when receiving a light is disassemble the head to check if it is all well done, it usually is not (to varying extend) so then I optimise it. It has saved me a couple of lights already.

poor reflow i guess… no idea what quality nightwatch is… i think for lights with such high output the assembly of such lights cant be speeded just to boost sales, but i doubt each light is individual made and checked for quality and stability and apply correct amount thermal paste etc maybe the cheapen out on that….

either way that is a warranty/ replacement issue that needs be taken care of.

From the 2nd picture, I see the LED dome has twisted from the substrate. Faulty emitter or improper gasket retaining?
Had a similar problem with a 6V XHP50.2

I don’t think this is a common occurrence. I reflowed a new LED (and better bining) than bother with any claim to the seller.
Cree seems to have resumed production of the 3V XHP50.2s.

Depending on OPs modding abilities, Sofitn has the LED Link

I have not yet done any modding on lights. I’m an IT technician so I’m not completely useless when it comes to tech but soldering is not one of my skills unfortunately. I turned the light on again for a few mins today an the burn got worse btw. Hoping that Neal reply’s to my message and otherwise ill try and get a refund I guess. At that point I might try replace the LED since I don’t have much to lose if things go wrong.

Oh, it’ll get angry blue to violet. Best you not drive that fellow, the fumes will contaminate the reflector and the lens.
As for neal, he may be inclined to respond, probably could send you a new LED board. But don’t hold your breath!
But then again you’ll have to do some soldering.

Shoot, that’s really disheartening to see in such an interesting light.

Based on a teardown I’ve seen, getting the board out shouldn’t be hard, though I’ve never tried to reflow a multi-emitter light before (hopefully it doesn’t come to that).
I’ve found Sofirn to be great for getting emitters cheaply, but you’ll have to see if the tint you need is in stock. Right now it looks like it’s just 6500K.

I’ve never seen a light where the gaskets sit on the LEDs. interesting.

They look like they do but the gasket flairs out on the lower end on mine it almost touches.

I did notice one possible issue with the burnt LED. All the LEDS in the sales pictures, on mine and on your working 3 LEDS. They are all perfectly aligned except the burnt one is tilted.

Yea, I can see it too, I think. Ever so slight, maybe 2-4 degrees or so, tilted to the right.