1st MTG2 Build

Great idea Scotty with the penny. I filed a few down the other night, along with a couple of old aluminum stars.

Now that I’ve seen your idea for shaping them down I sure feel like I’ve wasted some time. Thanks for posting and look forward to seeing your completed build.

Um, y’all do realize don’t you that destroying pennies is a Federal offense? If ya just gotta do it, perhaps you shouldn’t proclaim it on a public forum.

Copper sheet is readily available. There are punched copper discs to be found on ebay, even the cheap copper stars that have a mask under the thermal pad are useful for projects such as these. Government monies are wasted badly enough already…

And I’d only drill a hole to mount the disc if I was planning a triple that had a hole in the center of the star. Otherwise, you’ve removed precious heat sink material from directly under the source…the emitter. There was an article about the path of the heat under the emitter, accompanied by spectrograph charts, that showed the heat tends to take a similar angle as the beam of light itself. So the area directly under the emitter is crucial.

Would love to see these tests. We’re the emitters on stars with big heatsinks sucking the heat down? Is there any way to direct this heat outward towards the body?

If you draw a V that represents the radiant angle of the light coming out the front, extend the arms of the V down into an X and that’s kind of what the heat dispersal looks like under the emitter. The only real way to get the heat to disperse is to bottleneck it, making it spread out, much like blocking the light with a reflector to guide it. BUT, in so doing the path of heat dispersal is also slowed, causing the emitter to run hotter and thereby less efficiently. Heat is going to be radiant by it’s very nature, so giving it good contact will automatically result in it filling up all the sink material available, with ambient temperture being a key factor in removal from the surface. This is where the fins come into play. Are the fins adjacent to, above, or below the heat source? Would seem to me that fins below the heat source would be more of a sponge, wicking heat from the source to the outside air. Fins above the source are only going to come into play when everything is saturated and effectively backing up to the fins. Adjacent would be a compromise between those two factors.

I’m no engineer, just someone that’s been burned. lol I’ve worked outdoors in the Texas sun most of my life, radiant heat is a way of life. You DO NOT lean your forearms on a dark rusty metal gate in full Texas sun in August! Or the blue hood of a car. Or the dark green plastic slide some idiot put in the playground for my kid to play on. For me, it’s like running a water hose over a slanted sheet of plywood, the water will run straight down and leave the board if nothing stops it, put a deterrent in the way and the board will get wet on a wider path. Similarly, let the heat escape and it will take a straight path out. Block it, and it will back up and saturate everything. Right? So, getting a direct thermal path under the emitter and enough sink mass to radiate the heat out to the fins for the air to take away, and there’s your efficiency. Simple enough on the face value, more difficult than that in application. So now I can be shot down with all my ideas. :stuck_out_tongue:

Run an MT-G2 at 10.5 - 12 A and see where the heat goes…

Speaking of heat… #%$&, I destroyed my driver in a pathetic series of soldering whoopsies and and hurried shoddy repairs. I was so excited and so close I just knew I could make the repairs and get it to work. There goes $20. Will be placing an order with Richard tomorrow. I can salvage the chips to use on another build using reflow. I can do reflow but the soldering is still a work in progress. So a little break until more parts arrive.

What happened Scotty?

Sorry to hear about the bad luck. Great to see you have a stick-to-it attitude. Says way more that a easy success does.

Holy Hell it's nothing but LED!

Wow...that thing has GOT to get warm really quick (there just ain't much meat on a Convoy S* series), but most awesome!

What kind of power are you going to push thru it?

Hope it goes better round 2! :slight_smile:

RMM, I ordered the driver with a bunch of chips on the bottom, so I could not use the securing ring and had to solder the driver to the pill. Hind sight vs fore sight. That took a while to heat up to take the solder, I overloaded the tip and pill/ driver - didn’t secure the pill well and I got a huge blob of solder on the positive lead and the (sense resistor) chip and some of the chips you stacked really pretty. First fix I tore the plate or base thingy off of the board for the + contact. During the process of scraping, wicking the solder off I busted a resister off the other side. Fixed that after I found it. Ugh. Put it together and the positive just snapped off and I can’t see the trace or contact pad to re-attach.

Good news is I did not burn myself this time. That’s a first in a long time. :slight_smile:

Thanks Ima4wheeler.

Any driver using the 9.4kHz firmwares are prone to audible whine, no getting around it, it's not caused by any of the hardware but just the PWM frequency. They do it even with 7135s. It's most noticeable in the modes around 50%, it goes away completely at 100%. If you have one that doesn't squeal it doesn't mean anything except that you got lucky and nothing in your light happens to resonate in the 9-9.5kHz range.

9400Hz is a really annoying tone, but most humans can't hear 19,000Hz. The wiggly parts in the light (springs, switches, even the cell rubbing the I.D. of the tube) that make noise at 9.4kHz are probably also vibrating with the 19kHz firmwares, we just can't hear it.

Scotty, sounds like you need a bigger soldering iron or bigger tip. Using a higher temperature and lots of flux is also best when soldering to the pill. Generally if I have to hold the iron on the pill for more than 5-10 seconds before getting a good bond then something is wrong, the less time you are in contact with the pill the less overall heat you will transfer. It may seem counterintuitive but sometimes a higher tip temperature can end up causing less component damage.

There is a lot of thermal mass in the brass pills so in order to solder to them without heating up the whole assembly too much you need to be able to transfer enough heat fast enough into that particular section that it heats up to soldering temperature before the heat can be pulled away. That's not a very clear explanation is it? Pretty bad actually. I'll try another poor analogy. :)

Let's say we have a kitchen sink. In order for the solder to stick correctly the sink must be full of water (sufficient local temperature), but we want to minimize the amount of water going down the drain which will spill all over the floor if it overflows the small drain bucket it's connected to (amount of heat spread over the entire pill assembly, water spilling is sufficient heat to melt other components). The drain size is fixed (thermal conductivity of heat away from soldering area).

With a small tip and low temperature, it's like the water is barely outpacing the flow of the drain. It may eventually fill the sink (provide enough local heat for solder to flow and stick) but we will have drained a lot of water out of the sink before that happens, possibly creating a big mess on the floor (overheated driver). What we need is a larger, faster water spout (thicker tip / higher temperature / higher transfer). This way we can fill the sink very quickly before very much water has a chance to drain out and spill everywhere.

That's a very rough (and slightly inaccurate) analogy but it makes some sense.

To think about water in terms of electrical components is a bit odd! :stuck_out_tongue: But yeah, I see the reasoning. Might need a different tip to give better contact point for that greater need as well. I’m bad about wanting to use the same tip for everything.

What “human’s” can hear is a subjective term. My son picked up a bug on the driveway and then asked what the bug was saying. Really puzzled my wife and I, Mary leaned over very close and she said a high pitched sound was coming from the bug that she could detect if very close, Daniel was just holding him at waist level and could plainly hear it. Mary told him the bug was begging to be put back down, it’s afraid of heights. lol My daughter can also hear sounds that are way beyond me. She says it’s a youth thing. Some say I listened to far too much wattage in stereo for far too long. Who knows. But so far I’ve had great luck with Qlite’s making no noise. Not even that Daniel can hear. One of those things that may vary from driver to driver and person to person.

Wouldn’t have thought about all the tiny components vibrating with the resonance of the PWM. Interesting. A sonic disturbance that also creates light emission…

Edit: The M8 is using a Qlite with the FET mod and phase correct PWM at a lower frequency so that the modes work correctly. (so I’ve been told, this is over my head) I have it set up with 5 modes. I took it to Daniel and asked him if could hear anything, anything at all from the light, and gave him several seconds at each level. All he heard was the switch click. So my luck holds…

I’ve had one or two lights that I could hear a whine on, I think those were a couple that had electronic switches so I didn’t put a Qlite in em, mosquito repellent. Doesn’t bother me like it does some, nor does the PWM in the light itself. We have tons of construction work going on in our area, lots of dust in the air, it’s easy to see which lights are pulsing the light and which arent as the dust is either pinpoints in the night sky or streaming in the wind.

I can very faintly hear the FET driver on one or two different levels, but I adjusted them slightly to minimize this. Sometimes just changing the PWM value by 1 or 2 is enough to minimize the noise.

I can also hear NLITE on medium in certain flashlights. I guess my hearing isn't all gone yet! Even though the high frequency probably isn't audible itself I hypothesize that it is causing other object within the light to resonate at audible frequencies.

At any rate, the wine from the FET is very light and not objectionable to me at all. The only driver that really gets on my nerves is the old DRY driver... I can hear it loud and clear in every mode. In the BTU Shocker it's not so bad but in my 3T6 and ZY-T08 it bothers me.

Men lose the ability to hear high pitch whining noises is a survival mechanism. The older you get, the more survival mechanism you develop. Don't develop it and you may end up going insane and hurting yourself or others.

Another tip for soldering to pills. Before installing the driver, solder a couple blobs to the edge of the pill. Then when you place the driver, just solder the driver to the blobs. Focus the heat on the pill's blobs first. Once liquid, let the tip touch the driver and add solder as needed to bridge. The idea is to subject your driver to as little heat as possible.

Great tip, thanks! I’ll definitely try to remember that next time. Can’t solder the big pills for squat.

I'm pretty sure the Qlite is using the 19kHz fast-PWM, I've never heard one make noise. But take that same Qlite and flash it with the old version of luxdrv (9.4kHz phase-correct) and it'll whine in the upper-middle modes. Flash it again with Nlite (19kHz fast-PWM) and it goes back to being quiet again.

If you have one of these attiny13/FET hybrids and it changes modes like it should, then you know it's using one of the 9.4kHz firmwares (clicky or momentary doesn't make any difference).

The only trick I found to make a 9.4kHz driver quiet isn't going to be practical in the smaller lights...

That's a 220uF/16v, and there's still a little bit of noise, I finally settled on 470uF and that makes it totally silent.

Great tip about soldering blobs to the pill first. I learn so much on this forum!

Thanks all for the very helpful tips and education. I am learning as I go along and I enjoy the learning, at least I enjoy learning from others and what I read I just dislike learning by my mistakes. Worse and most disappointing is that I knew I was rushing and taking chances and not using the correct setup but I proceeded ahead anyways. I will be more deliberate when my replacement parts come in. I will also be getting some equipment that will work better and I’ll be using one of those magnifying glasses with the alligator clamp arms. I figure it’s not unlike like bicycling; I fell a lot at first and was frustrated at times but with perseverance and the help of others it became second nature to ride a bike.

It’s kinda funny. I see a lot of people in the ER that knew there was a good potential for trouble if they did the thing that caused them injury, but they did it anyway and always say, “I knew better than to do that!” I think the part that bothers me about this set-back is that I really did know better. I often learn a lot from my patients. Now if I could just remember those lessons.

You’re onto something there Scotty, learning is one thing, remembering it is something else altogether!

Sometimes you HAVE to learn from your own mistakes because the expense/pain/frustration is what makes it memorable. Just reading about it is easy enough to forget.

Thanks Comfy, that looks impressive! And yeah, I can see where it’d knock out application in a small light. Is that replacing the small ceramic cap? That’s just a much larger capacitor? How do you figure this kind of stuff out? Trial and error experience like Scotty is talking about or research?