# More MTG-2 goodness.



## The Understater (May 6, 2007)

How small can you make a set of lights that crank out 4k lumens?

How about this? (first of two).


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## kwarwick (Jun 12, 2004)

Hmmm... 2K lumens out of each? That's a lot o heat for such a small housing... how do you plan to keep them cool?


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## Vancbiker (May 25, 2005)

That nice saddle fit to the bars will help transfer some heat but I think your're going to need a fair bit of speed and cool air to keep that LED happy on a high setting.


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## The Understater (May 6, 2007)

Vancbiker said:


> That nice saddle fit to the bars will help transfer some heat but I think your're going to need a fair bit of speed and cool air to keep that LED happy on a high setting.


Actually it's slightly more sophisticated than that. Think copper core direct from the LED all the way to the handlebar.


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## mattthemuppet (Jul 16, 2004)

awesome, I love watching your work and I'm sure this'll be just as great as your helmet light.

I'm not 100% convinced by the minimalist max output approach, but you're not going to know if it works until you try it. I'm guessing that the driver will be elsewhere and unable to provide thermal monitoring? Still, your fingers aren't far away and they're pretty good thermal monitors 

Cool use of a T-slot cutter, if that's what it is? I salvaged some lovely hard steel rods from a laserjet at work to make some small ones for my next light, nothing as fancy as that though!


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## mattthemuppet (Jul 16, 2004)

forgot to say that you can now get MT-G2 on 20mm direct-to-copper stars from Intl-outdoor
Noctigon MT-G20 MCPCB & CREE MT-G2 P0 5000K 6V LED [Noctigon & CREE MT-G2] - $21.85 : Led Flashlight-International Outdoor Store
they're pretty popular with the peeps on BLF. You can also solder them to copper pills too - not quite as fancy as the pillar style set up you used on your helmet lights, but a lot easier and almost as good, especially if you get the pill very very flat and smooth.


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## troutie-mtb (Sep 20, 2007)

I like it. 
bars for cooling at last someone else giving it a go.


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## bwack (Oct 11, 2009)

Neat 
I'm also not completely convinced by the thermal conductivity (light to bars). It's the rough surface of the bars creating many air pockets between the light and it self that worries me. A silicon pad for heatsink (for example 3M thermally conductive interface pad) squeezed between them should give you better conductivity.. I haven't tried it myself so I don't know for sure. Just saying


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## The Understater (May 6, 2007)

I'll be applying some thermal grease to the light/bar interface, and the copper core will be directly touching the bar.
I have absolute confidence in the lights' ability to shed heat based on the performance of my helmet light, which at level three barely even gets warm.

Since the photos seem to have disappeared off that build thread, here are two new photos:


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## The Understater (May 6, 2007)

I've done some more work on the light heads.
The latest machining operation was to cut the grooves for the o-ring mounting system. I went in with a 2mm end mill first and then used a jeweller's ball nosed cutter to cut a round seating for the o-ring.


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## The Understater (May 6, 2007)

Here's a shot of one mounted on the piece of alloy I was using to turn the grooves.
I think I will use one o-ring that crosses over at the back instead of one per side. They grip pretty darn well, but in the event of a crash will allow the light heads to move.
I'm using the same system for the switch housing.


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## The Understater (May 6, 2007)

*Machining done.*

I've finished all the alloy machining finally.
I do still have to do the copper core, but I'll worry about that when these are back from the anodizers.
they are no their way to be anodized as I type.
I've made a new spacer to go under the stem, which has a mount for the plug. The spacer will be permanent, and the plug housing will be held in place with zip ties. That should keep it nice and secure and out of the way when I don't have the battery connected. The whole idea of this build is to have it as unobtrusive as possible so I never really need to take them off.
The spacer could have been machined a lot tidier, but what the hell. No-one will really notice it.


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## Toaster79 (Apr 5, 2010)

You're a wizzard  That's all I can say!


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## machine4321 (Jun 3, 2011)

The Understater said:


> I'll be applying some thermal grease to the light/bar interface, and the copper core will be directly touching the bar.
> I have absolute confidence in the lights' ability to shed heat based on the performance of my helmet light, which at level three barely even gets warm.
> 
> Since the photos seem to have disappeared off that build thread, here are two new photos:
> ...


That green helmet just makes those lights look so awsome. Im sure there has been a fro reference already?


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## stu44 (Mar 28, 2007)

Looking great, how are you driving these and what battery??


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## The Understater (May 6, 2007)

Hi Stu.
I'll be using a Taskled B3Flex set to 3 amps and a 5 cell 18.5v pack made with 3400mah Panasonic 18650 cells.

I was running my helmet set with a four cell pack, but was struggling to supply enough juice. The five cell pack handles it easily and is the highest voltage the B3Flex can handle.

I have all my stuff back from the anodizers and a new roll of solder, so I should hurry up and get them finished off. I'm a bit slammed at work at the moment, but I want to have it up and running by next week.


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## kwarwick (Jun 12, 2004)

This thread has inspired me to build yet another light bike light, even though I don't need one. I've got parts that need to be installed in something ;-)

The plan at this point is a single MT-G2 on Noctigon copper MCPBC, installed in the M36 EasytoLED housing, and driven with a H6flex. I want the ability to drive the MT-G2 beyond 3 amps, hence the driver choice. In order to fit this driver I will need to flip the pill over and install the LED in the pocket that would normally hold the driver so that the 33mm H6flex driver can sit on the flat side.

Only part I'm not sure about is the reflector/optics to use. I've got a couple of P7 reflectors about the right size that I will try out, but I've heard that they don't generally work well with the MT-G2 so I'm still prowling for the best solution.


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## The Understater (May 6, 2007)

kwarwick said:


> This thread has inspired me to build yet another light bike light, even though I don't need one. I've got parts that need to be installed in something ;-)
> 
> The plan at this point is a single MT-G2 on Noctigon copper MCPBC, installed in the M36 EasytoLED housing, and driven with a H6flex. I want the ability to drive the MT-G2 beyond 3 amps, hence the driver choice. In order to fit this driver I will need to flip the pill over and install the LED in the pocket that would normally hold the driver so that the 33mm H6flex driver can sit on the flat side.
> 
> Only part I'm not sure about is the reflector/optics to use. I've got a couple of P7 reflectors about the right size that I will try out, but I've heard that they don't generally work well with the MT-G2 so I'm still prowling for the best solution.


Glad I could inspire you.
The ahorton aspherics work great. I'll be interested to see what other optics you can find.


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## The Understater (May 6, 2007)

Well, I still have a battery pack to finish wiring up (just as soon as the plug I need arrives, but I've finally finished fitting up the lights.

Rather than attempt to describe it, why don't I just post up a bunch of photos?








screwing in the led with long nose pliers.







copper core filed down.. it doesn't matter that I went through the anodizing a bit.







Quick modification of the stem to fit the wires through.







B3Flex wired up and pushed into it's heatsink.







Sugru!







Spot the lights!


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## The Understater (May 6, 2007)

*But does it work????*
















Yes, it works.
First ride tomorrow night if the weather comes right.


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## Fourtrax (Mar 17, 2013)

Impressive! Any way to check how well the heat transfer to the bars is working? I.e case temp at some time intervals on high both on and off the bars. Just curious.


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## The Understater (May 6, 2007)

Fourtrax said:


> Impressive! Any way to check how well the heat transfer to the bars is working? I.e case temp at some time intervals on high both on and off the bars. Just curious.


Yup!
Checking heat transfer and heat management generally is easy. The LEDs will run quite happily at 85 degrees centigrade, which is too hot to comfortably touch. So all I had to do was turn them on and see if anything got too hot to touch. Easy.

I have it running in duo mode, toggling between high and low beams, and I've set high to level 5 which should be the full 3 amps.

Running it on low at level 2 of 3 (so theoretically level 3?) inside at room temperature with no airflow, after 10 minutes the light heads were still cool to the touch.

Bumping low beam up to it's highest setting, and repeating, after 10 minutes the light heads were hot to touch, but I could keep holding them with no discomfort. The bars around the light heads were warm to the touch.... Once again, inside with no airflow.

I didn't try it on high beam, or off the bars, because, well what would be the point? They'll never experience that in actual use.

I call that a win.


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## Toaster79 (Apr 5, 2010)

Great! Now all you need is a pair of copper lock-on grips and you're all set for the winter with no gloves


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## Fourtrax (Mar 17, 2013)

The Understater said:


> I didn't try it on high beam, or off the bars, because, well what would be the point? They'll never experience that in actual use.


Ya, not practical since they won't ever run that way. It's the engineer in me that wanted to see real numbers on just how well it is working.  sounds like it will work just fine. Are there any issues running with no lens covering. I would have thought that dust on the dome would eventually cause a problem with the high heat.


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## random walk (Jan 12, 2010)

The Understater said:


> The ahorton aspherics work great.


Did you get yours from BLF? If not, from where and what are the specs?

Love the art and science on this build BTW.


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## Vancbiker (May 25, 2005)

Is that a couple o-rings I see at the top of the threads on the copper post? If so, very nice detail!


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## The Understater (May 6, 2007)

Vancbiker said:


> Is that a couple o-rings I see at the top of the threads on the copper post? If so, very nice detail!


Sure is. I was only going to fit one, but that post needed two to get the rotation just right for the wire to line up with it's hole. I sealed up the backs of the wires with some metal epoxy. I didn't photograph it, but there are glass covers on the fronts of the lights, just no lenses.


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## rschultz101 (Oct 5, 2009)

how was the ride ? too bright on the tire ?


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## The Understater (May 6, 2007)

rschultz101 said:


> how was the ride ? too bright on the tire ?


The ride was great. No issue with the tire at all.
Without optics they flood like hell, as you can imagine. This is pretty much what I wanted, but if I was going to spit hairs, I would like maybe 15% less flood and more throw to even out the helmet and bar beams. But as I said, that is splitting hairs.
As it is the bar lights pick up everything in my peripheral vision and the helmet does the rest in grand style. I can use the helmet by itself, and I have when I've had to loan out a battery, but it has a very sharp cut-off, so everything not in the beam is pretty much dark. I wouldn't really want to use the bar lights by themselves, but to be fair, that is probably because my eyes are adjusted to having so much light.

At the moment I have only snapped a shot with my phone, which doesn't pick up as much light as I'm seeing... particularly the throw, which is much better than the picture shows, but this should give you an idea of the flood. Also attached is a shot of the battery pack and connector.

Oh, and I can tilt the lights up considerably if I want.


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