MT-G2 Driver

cbsmith111

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Jun 23, 2014
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I have an older olight that I think would be pretty easy to switch components in. I have been interested in trying one of the MT-G2 leds, but I have absolutely no clue how to select a driver. I just don't have a good grasp on the finer points of driver/led matching. The light uses 3xcr123 or 2x18650 with an extension tube. If anyone could point me to an appropriate driver (preferably not very expensive) that will get good output with this emitter, with or without an explanation as to why it will work, I would greatly appreciate it.
 

jonwkng

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Hi cbsmith111!

I'm not sure what you could use for both the options you mentioned, but if 2x Li-Ion batteries are good enough, you might want to look into the Zener Diode Mod. Works fine for 6-8V. You can get ready-made Zener Mod Q-LITE or FET drivers at mtnelectronics, or you could buy the kit and do the mod yourself.
 

Conte

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I'm not sure about three cr123's but it should run fine off two cr123's just not as bright.

2x18650's will work great, but you'll need ones that can crank out the current like high capacity lico or IMR's to get max output.

I wrote a how to on the zener mod if you have the skills:
http://www.candlepowerforums.com/vb...3-The-IMR-Enhanced-Zener-Mod-to-run-the-MT-G2

Otherwise, as mentioned, mtnelectronics has ready made zener drivers.
 

Rod911

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Which light are you planning to mod?

If it is already powered by at least 2*18650, the existing driver should work with the MT-G2. The only thing is, if, let's say, the original LED was an XP-G, then the driver would have probably been driving its max at 1.5A. If it was an XM-L, then maybe the driver was driving it at 3.0A. If its the former, then it obviously won't be brighter compared to it being driven at 3.0A. Having said that though, again, depending on the light, you'd probably want it driven at 5.0A mark to get the light in the 2500 lumens range. That can only be done by modding the existing driver, buying a driver already at 5.0A (limited to the driver cavity size of your light) or going for a 7135 based driver, zener mod it, and stack as many 7135 chips to your heart's content.

What ever you go with, let us know how it pans out.
 

cbsmith111

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I looked at the drivers from Mountain Electronics, and I believe I can handle that. Actually for $15 I think I would rather just buy a host for it than Modify my already working light.

What I would love to do is put it in a maglite with some 26650s, but I'm sure it would be several times more expensive, and I'm not entirely sure what I would need to make it work.
 

cbsmith111

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A local store has the new style incan 2d maglites on sale for $10. I would really like that a lot better than a little cheap Chinese host. I think I could figure out how to wire the driver to the switch and the driver to the led. I'm assuming though, that it would require an aluminum, brass, etc. Insert in order to mount the boards and act as a heat sink as well as a different reflector. Could anyone pint me towards something that would work or show me an example of what to make? Anything else I'm overlooking feel free to point it out.
 

Conte

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Did you look at my link ?
It show's a 2D mag build that I did. An easy one at that. Kind of.

I was thinking of writing a how to article but it's a work in progress as some of the parts I got were not "drop in" and I've since ordered another reflector assembly to test for better fit.

The build that I did works great with one issue. It's not enough heat sink to maintain full power. It basically runs like a Turbo mode.
It can maintain medium power for an indefinite amount of time, at which it's output is equivalent to an XML2, but at full it can only maintain it for about 5-10 mins before it starts to throttle down. So far it's not a problem cause it's still proves to be a very useful rig.

If you like this idea, I can give you more info when the next test reflector comes in.
 

cbsmith111

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Those heatsinks are very reasonably priced. The MT-G2 I was looking at though is mounted on a 20mm mcpcb. Those hinksinks have a mounting surface that is 14.5mm. Would it hurt to center it on there or would it hanging off the edges cause problems? Can I make it work or do I need to mount it directly or find one on a smaller mcpcb? Also the driver is 17mm diameter, and the cavity in the bottom of the DHS heatsink is larger than that. How would I make it rest on the bottom properly. Sorry, but I've never done anything like this and I don't want to order parts I can't use.

Conte, I would love any information I can get for ideas on this build or one similar to it. I don't usually run my flashlights on super high modes for extended periods of time, but I would like to be able to use it for at least several minutes on high in the case of an emergency.
 
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Conte

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The reflector I have now takes a 20mm LED no problem. I had to shave a bit off the front of the slug so that the reflector would sit deep enough to properly sendwich the LED but that's easy. A few mins with sandpaper on a flat surface.

The rear of the reflector I got had an oddball 22-24mm opening and had to use some trickery.

The reflector I have on order looks like it will be smaller, maybe the typical 20-21mm. IN which case, you just solder the driver to an adapter board like this:
http://www.mtnelectronics.com/opencart/index.php?route=product/product&path=25_72&product_id=117

The reflector I have not did not sit properly in the Mag head. It would fit, but I could not screw on the bezel ring completely. I had to lathe the reflector to fit it.
The reflector I have on order, looks like the might have a narrower lip for a better fit but I won't know for sure until it comes in.

To be honest, that was the hardest part of my build. It's easy to do really, IF you have access to a lathe and know the basics of how to use it, or know someone who can do it for you.

Otherwise, I've heard of other people fitting it with just a file, sandpaper, and a lot of patience.

Once you get that reflector to fit, the rest of the job is pretty much hotwire 101 and it's a decent entry level LED modding project.

If you don't mind waiting a bit, I'll be able to better inform you once the reflector I have on order comes in.
I ordered about a week ago, and an expecting it in maybe another week from now. Then I'll be able to give you proper measurements.
 
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cbsmith111

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Jun 23, 2014
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I was thinking I could get one of the P7 or DHS flat top and mount some aluminum pipe sections around the mounting surface to support the overhang and transfer heat better. Any thoughts on this method. Also would the heatsinks from the sandwich shoppe fit this role better? I see most people mentioning the need for the reflector hole to fit down past the mcpcb, but most commercial models I see sit on top with a hole just big enough for the emitter to show. Is there an advantage to one way or the other. I hope most of that made a little sense.
 

Conte

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I think the ones that go thru' the reflector hole will allow you to focus more throw.
The MT-G2 is a beast. It don't have throw, it has what I call punch.
When you wind it up, it blasts out a wall of light, mostly in the form of a flood, but jsut so much output, it punches as far as some lights can throw.

Also, some smaller emitters are so small, you need to raise the MC up that high into the reflector just to get the emitter far enough into it for it to actually work. LEDS like the XP-g2 and Nichia are like that. They don't match well with some generic reflectors like the XML and MT-G2 do.

If the opening is wide enough, you'll have no problem getting enough MT-G2 up into the reflector.

I'm not sure what you're talking about with the Flat top, and I'm not familiar with the sandwich shoppe reflector.
You would have to provide me some links.

The heatsinks you are talking about are definitely a better way of doing things from a thermal standpoint. But they may also be more complicated.
I can't speak for them cause I've never done that kind of build before.
In some cases they are much more advanced assemblies.
 
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