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  1. #1
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    Semi-first attempt at XM-L build

    OK, I built my first lite using by following the awesome, idiot-proof, instructions in Pucked Up's thread:
    Very Easy XM-L Build

    That got me thinking of trying a slightly more ambitious project. I had a junk, non working, SnapOn flashlight that had a nicely machined and anodized head. (BTW, I didn't take pics as I built so I just disassembled things for this thread)
    The Donor:


    Carclo 26.5mm optics 26.5mm Carclo Optics - LED Supply.com fit the head perfectly.


    I then measured the head unit and subtracted the optic length to get the right thickness for the heatsink puck...




    ...and glued the XM-L star in place.


    Next up was machining the base piece. In order to keep the light as small and light as possible I decided to mount the driver remotely. That also made machining the base far easier.


    I found this case Plastic Box Enclosure Case Hobby Electronic Project ABS E203 | eBay That just barely fit the driver.


    The rest of the parts are here:
    Battery pack:1x Sanyo Li ion 18650 14 8V 2600mAh Battery Pack with PCM Plug 4Cells to 4S1P X | eBay

    Switch: Component - Switch: on-off switch with LED Indicator (1' long) with Male & Female Trail-Tech coaxis connector

    Cables: Connector/Adaptor: Trail-Tech Coaxis Lockable Male Plug with 6" Prewire

    http://www.batteryspace.com/Connecto...9-Prewire.aspx

    And the final result:








    Thanks again to Puck Up who made getting started much easier.
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  2. #2
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    Very well done!
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    Looks good! I'm always looking at cheap flashlights and taking them apart at stores to see if the housings are worth working on.

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    well done dude! really nice! did you machine the base yourself?

    uhm you forgot to link where you got your led from.... is it from the same place that Pucked got his from?
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  5. #5
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    Quote Originally Posted by Muscleflex View Post
    well done dude! really nice! did you machine the base yourself?

    uhm you forgot to link where you got your led from.... is it from the same place that Pucked got his from?
    Thanks, yes, I work in a machine shop.
    I used the same LED and driver as in the thread.
    However, I'll never use DX again. I waited over five weeks for delivery of the driver.
    I found what looks to be a great driver from Illumination Supply.
    https://illuminationsupply.com/8xamc...a2624baa697c44It'll drive the XM-L to a full 3amps and I had them in less than a week. You'll need to keep battery voltage down to under 6V though.
    Also picked up a couple of the new gen 2 XM-Ls from them for the next project; refurbing an old classic NiteRider dual beam.
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  6. #6
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    I ordered the same driver, an XML U2 and optics from illuminationsupply as well. Parts aren't as cheap as DX, and shipping isn't free, but it's fair ($2) and delivery was quick.
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  7. #7
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    Quote Originally Posted by random walk View Post
    Parts aren't as cheap as DX, and shipping isn't free, but it's fair ($2) and delivery was quick.
    Exactly.
    They're really not even far off in cost; maybe $5 difference on two LEDs and two drivers, including shipping.
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  8. #8
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    Quote Originally Posted by roxtar View Post
    ...It'll drive the XM-L to a full 3amps and I had them in less than a week. You'll need to keep battery voltage down to under 6V though.
    you may already know this, but I'm going to add this just in case:

    That Illumination supply 7135 driver you linked is a linear driver, meaning Vin needs to be as close to Vout as possible. If you're running a single LED with a ~3.2vf, and you're planning on running Lithium batteries, then you really need to run a 1S 3.7V battery pack to avoid excessive heat issues. Actually, since the absolute max a 7135 chip can take is 7.0Vin, you couldn't run a 2S lithium pack anyway, they're 7.4V nominal and come off the charger at about 8.4V hot.

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    Quote Originally Posted by adrenalnjunky View Post
    you may already know this, but I'm going to add this just in case:

    That Illumination supply 7135 driver you linked is a linear driver, meaning Vin needs to be as close to Vout as possible. If you're running a single LED with a ~3.2vf, and you're planning on running Lithium batteries, then you really need to run a 1S 3.7V battery pack to avoid excessive heat issues. Actually, since the absolute max a 7135 chip can take is 7.0Vin, you couldn't run a 2S lithium pack anyway, they're 7.4V nominal and come off the charger at about 8.4V hot.
    I have this 1S3P pack on order for this driver:
    Li-ion 18650 Battery: 3.7 V 7800mah (28.86wh) battery module with PCB
    That should be fine, right?
    If I'm starting to understand this, it should get me about 2-1/2 hrs on high.
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    Quote Originally Posted by roxtar View Post
    I have this 1S3P pack on order for this driver:
    Li-ion 18650 Battery: 3.7 V 7800mah (28.86wh) battery module with PCB
    That should be fine, right?
    If I'm starting to understand this, it should get me about 2-1/2 hrs on high.
    Yep - you're spot-on. That pack will be fine.

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    ^^goodness you guys just made it even more confusing for me!!!!
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    Quote Originally Posted by Muscleflex View Post
    ^^goodness you guys just made it even more confusing for me!!!!
    Really? What's confusing and we'll help u sort it out.

    roxtar's build he posted here is using a buck-style driver, which requires more voltage in than voltage out (the Vf of the led string you're trying to power).

    He was stating that he's found the linear driver that Illumination supply (and other places) sell as a cheap 3amp driver for pushing XM-L's. Linear-style drivers require the Vin to be very close to the Vout - the difference has to be dissipated by the driver as heat, so you want the smallest difference you can.

    I expect he will either swap his driver and battery pack in his current build, or he's planning another build using the 3.7v pack and the 7135 driver and one XM-L.

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    ^^awesome! for starters, you already helped just by explaning Vin! I have always wondered what it meant. Never knew it just stands for Voltage In.

    Regarding Buck Drivers - what are they? are buck drivers really different to normal circular drivers I see on deluxe extreme? or are they all the same and they're all called buck drivers?
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    Quote Originally Posted by adrenalnjunky View Post
    Really? What's confusing and we'll help u sort it out.

    roxtar's build he posted here is using a buck-style driver, which requires more voltage in than voltage out (the Vf of the led string you're trying to power).

    He was stating that he's found the linear driver that Illumination supply (and other places) sell as a cheap 3amp driver for pushing XM-L's. Linear-style drivers require the Vin to be very close to the Vout - the difference has to be dissipated by the driver as heat, so you want the smallest difference you can.

    I expect he will either swap his driver and battery pack in his current build, or he's planning another build using the 3.7v pack and the 7135 driver and one XM-L.
    I'd like to say I know the difference between a linear driver, a buck driver, and a buck private but I don't.
    I just read the driver specs and it said the Vin was 2.8V-6V so I figured a 3.7V battery pack would work fine.
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    Great build. I can't wait to see your retro build next. Remember to take pics as you go.
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  16. #16
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    Quote Originally Posted by Muscleflex View Post
    ^^awesome! for starters, you already helped just by explaning Vin! I have always wondered what it meant. Never knew it just stands for Voltage In.

    Regarding Buck Drivers - what are they? are buck drivers really different to normal circular drivers I see on deluxe extreme? or are they all the same and they're all called buck drivers?
    Shape isn't really a determining feature - I've seen square and round in all types. Size can vary, but it is a physical size of the components on the driver board.

    without getting all technical in the electrical engineering stuff (cause I can't get technical about that stuff) here's my "layman's" definition of them:

    Buck Driver (step-down controller): Requires a 1.5-2 volt overhead more than the Vforward of your string of LED's being driven. The driver takes the input, and through some magical switching and stuff, controls the regulates the voltage and current to whatever the output requirement is. Buck drivers can be very efficient if quality components are used in thier construction. TaskLED quotes ~95% efficiency for some of their buck drivers). Cheaper dealextreme style drivers uses less advanced components, but still have good efficiency.


    Boost Driver (step-up controller): Requires a VIn lower than the VForward of your string of LEDs. Again some magic happens and the output is regulated to whatever specs you've programmed, as long as the source voltage doesn't drop below that overhead, and/or that the current ability of the battery drop below the current you're requesting it provide to your LEDs. Like a buck driver, boost drivers can be extremely efficient in some cases.

    Boost/Buck: Yeah - there are drivers (not typically used in our lights), that have circuitry that allow the driver to react to changing input voltages and act in whatever fashion is required. The power source must be able of providing current greater than the output rating of the driver.

    Linear: Linear drivers incorporate Linear regulator chips. The 7135 is a model designation of a particular model of linear regulator that has a fixed output current of either 350ma or 380ma depending on the version . That 7135 driver uses 8 of the 380ma rated chips in series to provide 3040mh of current output. ( the original versions of this chip were rated at 350ma, resulting in a 2800ma driver). The chips again do some magic between input voltage and output voltage (which is determined by the LED) and the differential between the 2 is dissipated as heat. (It's acting like a fancy resistor.) Linear regulators can be more inefficient than a buck or boost driver, cause there's less advanced methods employed in regulating the output.
    Last edited by adrenalnjunky; 01-08-2013 at 07:02 AM.

  17. #17
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    Quote Originally Posted by adrenalnjunky View Post
    Shape isn't really a determining feature - I've seen square and round in all types. Size can vary, but it is a physical size of the components on the driver board.

    without getting all technical in the electrical engineering stuff (cause I can't get technical about that stuff) here's my "layman's" definition of them:

    Buck Driver (step-down controller): Requires a 1.5-2 volt overhead more than the Vforward of your string of LED's being driven. The driver takes the input, and through some magical switching and stuff, controls the regulates the voltage and current to whatever the output requirement is. Buck drivers can be very efficient if quality components are used in thier construction. TaskLED quotes ~95% efficiency for some of thier buck drivers). Cheaper dealextreme style drivers uses less advanced components, but still have good efficiency.


    Boost Driver (step-up controller): Requires a VIn lower than the VForward of your string of LEDs. Again some magic happens and the output is regulated to whatever specs you've programmed, as long as the source voltage doesn't drop below that overhead, and/or that the current ability of the battery drop below the current you're requesting it provide to your LEDs. Like a buck driver, boost drivers can be extremely efficient in some cases.

    Boost/Buck: Yeah - there are drivers (not typically used in our lights), that have circuitry that allow the driver to react to changing input voltages and act in whatever fashion is required. The powersource must be able of providing current greater than the output rating of the driver.

    Linear: Linear drivers incorporate Linear regulator chips. The 7135 is a model designation of a particular model of linear regulator that has a fixed output current of . That 7135 driver uses 8 of these chips in series to provide 3040mh of currentoutput. that means each chip is providing 380mah of current. ( the original versions of this chip were rated at 350ma, resulting in a 2800ma driver). The chips again do some magic between input voltage and output voltage (which is determined by the LED) and the differential between the 2 is dissipated as heat. (It's acting like a fancy resistor.) Linear regulators can be more inefficient than a buck or boost driver, cause there's less advanced methods employed in regulating the output.
    Very nice explanation. Even I understood most of it.
    Couple questions;
    -I've looked at the specs and can't find the voltage of the XM-L LED. What is it?
    -When using more than one LED, do you wire them in series or parallel? How does this effect the voltage and amperage requirements from the driver?
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    On an LED, the Vforward (Vf) varies based on the current supplied to it - the higher the current, the higher the Vf. It varies for each class of LED - the best way to research it is to check the data sheets from Cree (or the manufacturer) .

    For a XM-L2, they state @ 3A current, the Vf is 3.3V, but at 700ma it is 2.85V

    Remember - the brightness if a LED is based on the current supplied, the voltage required is a function of the current.

    When wired in series at a particular current, LED's combine their total Vf. So if you used a 3A driver, they would present a 6.6V Vf.

    When wired parallel, they share whatever current provided, so if your driver were a 3A max output, each LED would receive 1.5A of current, and at that current each would have a Vf of 3.05v. the driver would only see this 3.05Vf. Unfortunately this also means the LEDs would be running at 50% output. To get back to max, you'd have to use a driver that could supply 6A total, since an XM-L is a 3A max current LED.

    wiring in Parallel might also have some detractions, such as LED's that aren't exactly perfectly matched, but typically there aren't huge issues with it.

    Depending on your driver requirements, # of LED's, or battery setups, or even the physical size of your housing, you might be forced to run one particular type or style of driver.

    Clear as mud?
    Last edited by adrenalnjunky; 01-08-2013 at 07:04 AM.

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    Thanks for the patience and explanations! I'll have to read more into this at work this morning!!!
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    Quote Originally Posted by Muscleflex View Post
    Thanks for the patience and explanations! I'll have to read more into this at work this morning!!!
    X2
    Thanks
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  21. #21
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    Those explanations would go well in wmac's Noob guide.
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  22. #22
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    Quote Originally Posted by adrenalnjunky View Post
    On an LED, the Vforward (Vf) varies based on the current supplied to it - the higher the current, the higher the Vf. It varies for each class of LED - the best way to research it is to check the data sheets from Cree (or the manufacturer) .

    For a XM-L2, they state @ 3A current, the Vf is 3.3V, but at 700ma it is 2.85V

    Remember - the brightness if a LED is based on the current supplied, the voltage required is a function of the current.

    When wired in series at a particular current, LED's combine their total Vf. So if you used a 3A driver, they would present a 6.6V Vf.

    When wired parallel, they share whatever current provided, so if your driver were a 3A max output, each LED would receive 1.5A of current, and at that current each would have a Vf of 3.05v. the driver would only see this 3.05Vf. Unfortunately this also means the LEDs would be running at 50% output. To get back to max, you'd have to use a driver that could supply 6A total, since an XM-L is a 3A max current LED.

    wiring in Parallel might also have some detractions, such as LED's that aren't exactly perfectly matched, but typically there aren't huge issues with it.

    Depending on your driver requirements, # of LED's, or battery setups, or even the physical size of your housing, you might be forced to run one particular type or style of driver.

    Clear as mud?
    So if I were to wire 3 XM-Ls in series, would this linear driver work if I used 18650s in a 2S configuration?
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    No - that wouldn't work.

    each XM-L in series driven at 3A adds about 3.3V to the total Vf. That would be about 9.9vf in your scenario. For a Linear driver Vf needs to approximate the input voltage from the battery, without falling below. A 2S lithium pack will be 8.4v hot off the charger, and 7.4v nominal, so it would never get up to the Vf.

    If you parallel the 3 emitters, then you'd be able to wire your battery 1S for a 3.7v nominal voltage. but if your driver is 3A output, that 3A is now divided between the 3 emitters, so they effectively only get 1A each. An XM-L @ 1A is only about ~375lumen output, so 1125lm total. You'd be jumping through a lot of hoops, and adding a lot of weight and size just to get the same light output as one of the XM-l's can do if driven at 3A by itself.

    Plus - if youre talking about the budget 7135-style linear emitter, it has a voltage max of 6v, so you couldn't plug a 2S pack into it anyway. The Lflex can handle a 2S pack, if you were going to run a 2XM-L setup in series - and it can drive @ 3A if you want.

  24. #24
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    Cool, thanks
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