Build Using New Host from Mountain Electronics

The bottom of the reflector looks pretty wide. Did you have any trouble with clearance between the bottom of the reflector and the wiring soldered to the LED board?

Hotspot is definitely bigger it was hard to get a picture of last night but you can see from the picture the flood is definitely different.

I had absolutely no issues with the reflector hitting, I did make sure that my solder joints weren’t huge though. If anything it hits the screws used to hold the board down. I also use one of the 3m gaskets from mountain instead of the paper sticker that is supplied.

I was also concerned about the solder joints hitting. If you get them pretty flat it isn't an issue (but should be insulated) because the reflector does seem to hit the mounting screws before hitting the joints. As another benefit it seems to help protect the dome of the MT-G2 which can be easily damaged by a reflector tightening onto it (again, don't ask me how I know )

sorry… I was trying to buy more of this host… and regret I didn’t buy more :frowning:
but the new 26650 host from Mountain electronic looks similar enough :slight_smile:

it’s a beautiful host and plenty heat sink, the only issue I have with this light is the pill are for LED is too deep.
the LED couldn’t get close enough to the reflector, heck the reflector didn’t even touch the MCPB.
I was dry testing it by putting the noctigon MCPB on top of 2 copper pennies to make it a perfect fit.
how did you put yours?

Hmmm, there is an indication of some type of void in there. Question is, how large is it. We may be be seeing the only solder there is or there may be solder under most of the emitter.

That's one thing I don't like about the Notigons. The copper board is not pressed up like in the Sinkpads. I quite buying MT-G2's premounted on boards for that reason. I rather reflow myself and get it right.

The void may have cause the failure or it may have only contributed to it. At that current, any gap probably is fatal. I guess the Dry would need to be tested for output using 3S cells and the voltage sensor bank shorted to know if excess voltage is delivered to the emitter. I don't currently have the knowledge or equipment to do that.

The old Noctigon boards like that do not have the thermal pads up. Get some new ones like the 3XP and you will see all are up (got a lot of them to know). Ask Hank for the newer batch that have the thermal pad at the same level.

it does look like a gap under the led, who knows how much of it is actually soldered to the mcpcb, and how much of it is hanging in the air.

i used sinkpad2 for mine mtg2, it has heatpad and contacts on the same hight, no gaps.

Been testing my Noctigon mounted MT-G2 at 10A and 11A for a few minutes at a time. I know that DBCStm has been also. I don't think that the issue here was the amount of solder under the emitter but that it simply received too much current.

RMM wrote:

Been testing my Noctigon mounted MT-G2 at 10A and 11A for a few minutes at a time. I know that DBCStm has been also. I don't think that the issue here was the amount of solder under the emitter but that it simply received too much current.

Moderator007 estimates possibly over 15-16 amps across that MT-G2. You've been testing at that current with voids between the thermal pad and emitter using Dry and then known safe driver?

I have no cells that can deliver 14-15A to an emitter. Either way, hooking up 3S cells to a 2S LED will probably burn it out regardless of how good the thermal joints are. We are talking about a near instantaneous type of damage.

Possible and could be the cause, but I think there are too many unknowns to make any real conclusions here.

EDIT:

I really would like to get to the bottom of this because I have been thinking about driving an MT-G2 with a Dry and 3S cells. It seems it has to be excess voltage or thermal failure. Current seems unlikely. Please check out my logic and correct and/or build on a realistic theory.

# of Cells 3
Likely voltage ater sag (guess) 4.05
Total Voltage 12.15
Tail Current 7
Watts Produced 85.05
Driver Efficiency (guess) 0.8
Watts to emitter 68.04
Emitter Vf at 16 amps 8
Amps to emitter 10.63125

Obviously, last 2 lines don't match. That is the point. Comfychair showed here that it seems to buck pretty good. That seems to increase the likelihood of this being a thermal failure. Has anyone else tried to push an MT-G2 hard with the new Dry driver?

What if I reflow the half dead one, then try to monitor the current and voltage w/ 3 cells. If it is a random spike i don’t think my DMM will pick it up though.

I would hate to waste a new good one again.

I finally took some night shots. The shed is about 40 yards away, the woods in the back are around 100 yards. I am aimed at the shed.

The camera and settings are:
Cannon Powershot S110
Manual Mode - Shutter Speed = 1”, Aperture Value = 8.0, ISO = 800

Low

Medium

High

Turbo

What is a good budget holster for this $10-$20.

I built a Convoy L2 with the old 20mm Dry driver and MTG. I added an extension tube and momentarily tried 3 x 26650 and got a 13A reading. It was just a quick on and off, I didn’t want to harm the MTG.

I need to know the diameter of the reflector in this host.

This is the size of the light

245MM*56MM*33MM

I need to know the reflector diameter. I want to know if a five LED reflector I have will fit.

I assume it’s the 56mm but I don’t have it in hand to measure. When I get home tonight I’ll measure it.

Thanks.

The photo of the led does show that some of the center pad is not touching the star. I ruined an MT-G2 the very same way and it only saw 8 amps. The burned out area of the led correlated directly to the spot where there was no solder under it, when I removed the led from the star.

I have seen this with the MT-G2 leds that came to me already soldered on the Noctigon stars.

I have reflowed every MT-G2 I had now, to make sure the center pad was touching and every one had too little solder under the led. I took the leds off and removed all of the crappy solder paste and used 60/40 and reflowed them back to the stars. I just do not trust any reflowed led/star from overseas any more, the solder paste many of them use is terrible and it does not flow at all. I reflow all the led/star combos I get, to make sure they are ok. I also press on the led domes on every one I reflow, (press till they cool), to make sure there isn't excess solder under the pads. It's the same with drivers. I always clean off that junk solder and replace with 60/40.

Over the years, I have seen so many leds not soldered correctly on stars from China, that I just reflow every one myself now and I have gotten to where I prefer to just buy loose leds and bare stars and do them all myself.

Oh, RMM, you need to inspect the ones you have using a magnifier. Then you should be able to see any gaps, but I would still tell everyone to go ahead and remove, clean and reflow any leds that are already soldered to Noctigon stars. Better safe than sorry.