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  1. #1
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    My first homemade light

    Well I have been hanging around on here for a few months in which time I have bought a lathe, built my work bench, fried 2 maxFlex drivers, and made my first light!
    Here it is...


    Its 4x XR-E with Carlco optics. 3 spots and one wide beam. I have set the driver to 1200mA max for the beam shots just so I can see if there is any difference between 1000mA and 1200mA. I had to cut away parts of the optic housings to allow for the LEDs to be soldered together. I think this may have spoilt the beam pattern. When I get my big camera charged I'll take some shots.



    Have I gone overboard with the slug that the LEDs are attached to? At 1200mA the case warms up pretty quickly. Its a nice tight fit into the case, helped along with some thermal paste. I havent had it running for long as I have some battery issues which I'll get into later.



    The driver is also thermally bonded to the slug, I found a nice piece of copper perfect for the job.



    Oh yeah, my battery problems.
    Initially I had a 12v NiMh hooked up. The light turned on but I couldnt get any change in brightness. This battery measured 13.86v straight off the charger. When I measured the vf of the LEDs it was 12.68v. That equates to 3.17v per LED. That seems pretty low to me. I expected them to be around 3.7v. I didnt measure the current but the brightness was similer to the 1000mA setting.
    I hooked up a 7.2v NiMh that I had lying around, 8.44v fresh off the charger. I get all the 5 brightness settings this time. I dont want to have it on for too long as not to push the driver too hard.
    Can some tell me what is happening with the 12v battery! I understand that the maxflex needs Vin < Vout, but when the vf of a CREE is given at 3.7v, Vout should be @ 14.8v. Or have I messed up somewhere along the way???

    Thanks to Trout for his assistance over on CPF and George from TaskLED for keeping me topped up with new drivers!
    I'll post some beam shots later.
    Andrew

  2. #2
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    Nice light there. Looks great.
    Since battery voltage is higher the voltage out you are in direct drive with the 12v battery. That's why you can't change brightness modes.
    The Cree LEDs often have lower Vf than stated. Great for efficiency, but can screw up your battery driver system when the Vin and Vout are close.
    Once again - Great work -
    So what are the other 2 maxflex in the pic for?
    You got the builder bug don't you.

  3. #3
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    Quote Originally Posted by odtexas
    Nice light there. Looks great.
    Since battery voltage is higher the voltage out you are in direct drive with the 12v battery. That's why you can't change brightness modes.
    The Cree LEDs often have lower Vf than stated. Great for efficiency, but can screw up your battery driver system when the Vin and Vout are close.
    Once again - Great work -
    So what are the other 2 maxflex in the pic for?
    You got the builder bug don't you.
    Thanks!
    I thought the battery was causing it to direct drive. Looking online now for some 18650s to rig up a 11.1v pack.
    Those two maxflexes are special ones! One went pop and released some of its magic smoke when I hooked up the battery for the first time. The red and black wires on the battery were wired the wrong way, ie. red on - and black on + Never thought to check the battery's polarity!
    George sent me a maxFlex 4 which has reverse polarity protection!
    The other one shorted against the light body when my dodgy knee gave way.

  4. #4
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    Sorry to hear about the carnage. We all have dead drivers and leds littered about our work areas, some blood and burnt flesh as well come to think of it.
    Three 18650's can work. Just fresh off the charger they can be a little over 4 volts each. So there may still be direct drive with fresh batteries for a bit. Just an FYI there.
    Should not hurt anything, but you may not have access to mode changes initially.
    Last edited by odtexas; 04-10-2009 at 12:38 PM.

  5. #5
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    First build? very nice indeed!
    i`ve been running a quad XR-E for a while now, its great!, so i know your gonna love yours,
    ouch, bad luck about the fried drivers $$$
    ..... i can see George rubbing his hands from here!
    what is the power connector off?
    ...Scun.thorpe, UK

  6. #6
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    Maybe a bit late, but a 5 cell 18650 and a bFlex would ensure regulation from start until cells are at minimum voltage and a 2.5-3hr runtime on high. Would not be able to overdrive to 1200mA though. Do you gain enough extra light to make up for the additional current and heat?

  7. #7
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    When I measured the vf of the LEDs it was 12.68v.
    Vancbiker, you would get away with a 4 cell pack (16v+ charged) and bFlex, or nFlex
    ...Scun.thorpe, UK

  8. #8
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    Thanks for the replies!
    I settled on the maxflex and the 12v battery ages ago. Now I have more infomation on the 18650 cells I'll look at using them instead!
    I took some beam shot pics but the photos dont do the light justice. Need to find the default settings be for the camera so it's a fair comparison too. There is a noticable increase from 1000mA to 1200mA. But that's in the garden! It may be different on the trail!

  9. #9
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    Quote Originally Posted by HEY HEY ITS HENDO
    Vancbiker, you would get away with a 4 cell pack (16v+ charged) and bFlex, or nFlex
    Pretty sure that setup falls out of regulation when cells are partway through their useful charge. I run the 18650s down to 3V. If his Vf is 12.68V and the bFlex needs ~1.1V over the Vf then 13.78V is the minimum battery pack voltage to stay regulated.

  10. #10
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    Your first attempt puts my latest ones to shame

    Cool light, it looks much smaller in the first pic compared to the last, almost thought it was two lights In the second pic it looks like the optic on the left side may be out of alignment, could that be part of the beam problem?

  11. #11
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    Nice one Piesoup and happy to have helped a little.
    You will now have a garage full of ali chips and swarfe .and be planning the next one.

  12. #12
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    Quote Originally Posted by HEY HEY ITS HENDO
    what is the power connector off?
    Its from a variable transformer I had lying around. The only problem is that there isnt anything stopping you connecting it the wrong way around.
    For my next light, which I have already started, I'll get a better connecter.

    Huffy, in the pic you are talking about, the LED stars are loose. when the slug they are sitting on is pushed into the body, they get forced up against the glass bezel. When I get my cateye mount, I'll fix it in with a grub screw wich will go through into the slug too.

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