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.
Reflector is 51mm, lens is 52mm.
Does anyone know if the stars on the DRY driver are functional?
Ouchy, was that 13 amps at the emitter?
I agree with O-L. Same experience here in that every mounted MT-G2 I have received had a gap. Luckily, I have had no failures, but then, I have not driven one past 6 or 7 amps yet. Well, also I reflowed them all really early on.
Gj, here is a Dry thread.
Thanks!
It was at the tail.
Yikes!!! Now you guys make me want to reflow my MTG2s just to be sure they’re done right.
Don't worry too much. I have run two of mine at 10A+ for over two minutes, no damage. I have built 10+ lights for others with MT-G2, no damage. DBCStm has been running his hard at 10A+, no damage. All of these are factory reflowed and no there isn't solder all the way to the edge of the pad on any of them.
IF there is ever damage due to insufficient solder under the emitter, I will warranty it as a manufacturer defect. All I'm saying is that this isn't what killed this emitter so don't get too worried about it. You could have an MT-G2 with a perfect reflow on a block of dry ice and it would probably still fry within a few seconds running 3S cells without a properly working buck driver.
Head diameter = 2.2”
Tube diameter = 1.3”
Anti-Roll Handle Piece = 1.9”
How would a holster work with the anti-roll piece on the handle by the tailcap.
Thank you!
This is a neat build! I’m going to have to build one…
I have 2 questions if you dont mind…
What (approx) resistor would I add to up the current to between 4 and 5 amps with 2 cells?
Would that resistor mod work for 3 cells as well, or would the driver go over 4-5 amps with 3 cells?
Thanks!
Thanks
No resistors (bridge resistors) w/ two cells gives you around 5A. As of right now don’t attempt 3 cells with resistors bridged until more info is figured out on if the driver is having issues with the MT-G2 and 3 cells.