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  1. #1
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    MTE P7 hack job bike light // 2.8 amps

    I call it tactical because I used some PIMP Weaver rifle scope rings and a schwiggitty Weaver base. I'm only estimating the 700lm b/c Mfgr's always over rate these...yet I'm running this at a full 2.8amps instead of the crappy amperage that the orig. MTE was spitting out.

    I've learned alot since November when I decided to replace the Nitehawk Raptor.

    -Incandescent lights requre 3x the current to achieve similar lighting.
    -Direct drive is okay for LED's...but has its pitfalls
    -You can't be lazy if you want to build a decent one.
    -I have an illness...this crap if fun!!


    I decided to hack the MTE SSC P7 flashlight up for this project so I'd have a good compliment to the MagicShine on my helmet. I don't have a mill or a lathe...so I needed a good host for the emitter that looked decent and fit my needs. I also...just like to tinker.



    I learned "the hard way" that high output LED's are low voltage / high amperage. (but not too high) With the Seoul Semiconductor P7 emitter, you need to try to keep a constant voltage around 3.7v. You can run low amperage for good run time and low light / high amperage for the opposite. (with my incandescent's...I'd +/- voltage to give it more/less output.

    Someone told me that I could "direct drive" the P7 with 4 lithium ion cells in parallel w/o hurting it. WRONG!!! I burned one up. You either need to drive it off one lithium ion cell, or use a circuit board to limit the voltage and current that you're sending the emitter. You can do it several ways, but I found some super-cheap boards ($3ea) that are 3.7-4.2v input / output, so I decided to do a 4x 18650 lithium ion cell pack in parallel wired through a decent switch to the boards. I got the boards from Hoffman Amplifiers.

    Here's a wiring diagram:


    I decided to just do a straight 2.8amp setup instead of a 2-stage setup. I don't see any reason to run it on 1.4amps if I have a 4-cell pack.

    Here's an example of the wiring...I didn't use the white switch pictured. We'll get to that:

    1x 1.4amp board:



    Adding the second board to give it a full 2.8amps:


    Here's the P7 on the other side of the heatsink:



    I hacked the MTE SSC P7 light about 4-5mm behind the lamp head. I bought a "cable gland", connectors, and trailtech switch from Battery Space.


  2. #2
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    The large "inside" nut on the gland was the perfect size to press-fit into the 19mm hole that was left in the back of the light when I cut it up. I rounded the corners off the nut and pressed it in for a watertight fit. The Trail Tech connector fit right in there and soldered to the base of the limiter boards. Screwed everything together:



    Now, all I had to do was build a battery pack and try to mount the thing:
    I got the pack from LuminousDIY and wired it 4p.

    Similar to this...except mine's in parallel...and I dremeled channels in it to keep it all "flush".


    Now, to mount it...I got a Weaver scope base and rings laying around...what the hey! It fits perfectly! Attach the base to pretty-much anything ya got laying around. I had a couple of NiteHawk bar mounts chillin:


    Switch:


    The whole whatevah:


    Mounted:





    I think I'm gonna add an extension to a seat bag for the battery pack. I have this little triangle bag...but not really into it.

  3. #3
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    The little circuit boards are only 17mm diameter. Looking at those pic's...they look easy to work with. They actually fit in the tube right in front of the scope rings. Here's a picture of one next to my thumbnail to give you an idea about the size of frustration:


    I removed this one from the orig. MTE b/c it was fried.

  4. #4
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    I had a little bit of concern with heat, so I added a heat sink from the local hobby shop. I think it's for an electric airplane motor.
    I had to drill and tap the head to attach it, but I flattened out the lip on the head and added some heat sink paste. IMO it's a little uglier now...but it definitely has a bit of character and will be safer on warm nights.



  5. #5
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    Success!!!





    I ran the light for a while yesterday with no fan blowing, and it started to heat up after a while. I turned a fan on med for a few minutes and I felt the heatsink fins and lamp head and it was noticeably cooler to the touch.





    Looks like full blast on a trail ride will be no problem at all.







    When compared to my Geoman light:

    -equal volume of light emitting from the unit

    -slightly spottier than the MS...the hot spot on the MS is broader

    -the emitters are def. different...the MS is a warm white / this one is a cool white...nice contrast when ran together though...I like it

    -the MS will obviously stay at full brightness longer b/c it's 2s/2p and this is 4p...but I don't think I'll notice any dimming while I'm on the trail b/c these two lights will have approx 3.5+hrs runtime...and I don't ride that long at night.





    My next project will most likely take advantage of the buck boards that are out there giving me full voltage over the entire runtime, but for my first build...I'm happy with the end result.









    I'd really like to build something rediculous next. Like a 4-5 p7 light...or maybe 2-3 Ostars...I dunno...I've been eyeballing the SST90 with that M-size LiFePo4 cell...run that sukka at 8amps...woohoo! I think since I don't have access to machine shop-type equipment...I'll have to go somewhat crude on the design. A huge block of aluminum for the heatsink. We'll see what comes along. For the price of an SST90, I can buy 3x p7's.

  6. #6
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    ....equal volume of light emitting from the unit

    -slightly spottier than the MS...the hot spot on the MS is broader

    -the emitters are def. different...the MS is a warm white / this one is a cool white...nice contrast when ran together though...I like it...
    I'm surprised that your mod isn't brighter than the M.S.
    I think someone said that the MS ran at 2.4A when on high. You did mention a difference in tint though. Sometimes it's hard to tell which one is brighter when their is a difference in tint. The only real way to know is to either measure the light coming out or to do an outside beam (throw) test. Of course both are using different reflectors so this is not scientific. It is quite possible though that it is just not enough difference in intensity between the two for the human eye to judge. I suppose that is good news if you're a MS owner.

    Oh, almost forgot....Very nice mod! EL would be proud.

  7. #7
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    I like it. Nice clean waterproof design.

    I humbly suggest to paint the heat sink black to match the light or red to match your hubs/accent color. And maybe round the sharp edges off the heat sink a bit before painting, in case of an OTB that snags body parts on the light. I kind of like the 'pissed-off Eagle /raised feather' look.

  8. #8
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    Quote Originally Posted by BrianMc
    I like it. Nice clean waterproof design.

    I humbly suggest to paint the heat sink black to match the light or red to match your hubs/accent color. And maybe round the sharp edges off the heat sink a bit before painting, in case of an OTB that snags body parts on the light. I kind of like the 'pissed-off Eagle /raised feather' look.
    Hmmm...I don't have any anodizing skeelz. I thought that paint would dampen the sinks ability to function.

    Will it work well with paint?

  9. #9
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    Cool project.
    I used that same torch for my first P7 experiment.
    It still runs great.

    It's way thicker and heavier than my Marwi lights and so I loan out the Torch light to other riders.

    Glad you like all the pics from my web site. Helps illustrate things nicely.

  10. #10
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    Thanks Doug! If it weren't for your site, I'd still be buying complete lights with inconsistant construction.

    FYI all: Hoffmanamps.com is a wealth of instruction and parts. The close-ups of the boards and plug pictured above are linked from his site b/c I couldn't do a better job on pics. (hope thats kosher, El34)

    I highly suggest you all go there for a look.
    Last edited by chelboed; 03-28-2010 at 08:18 AM.

  11. #11
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    Quote Originally Posted by chelboed
    Hmmm...I don't have any anodizing skeelz. I thought that paint would dampen the sinks ability to function.

    Will it work well with paint?
    No such skeelz here, either. Though it looks the kind of small project I might learn on. Maybe they have the same sink in red? Maybe flat black stove paint won't insulate. You won't want a thick layer of enamel, no. Still like the rufled feather/punk hair look.

    Another for Doug Hoffman aka EL34. Good site. Good stuff. Great to deal with. (No, I am neither related nor do I get kickbacks (his margins don't allow for it).

  12. #12
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    Thanks for the props boyz

  13. #13
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    Cool light! Those 7135 drivers are really nice to work with, I think DX sells them by the sheet (or at least they did). They can also be combined with other boards to add modes:

    http://www.candlepowerforums.com/vb/...d.php?t=195358

    I have a couple less used P7 MagLights using a 2 1/2 board setup (cut one of the 1400ma boards in half).

  14. #14
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    Yeah, the 7135 chips have been rock solid inside all my Marwi lights.

    Even though the two boards with 4 chips each are actually inside the aluminum heat sink, no failures yet.

    I've got maybe 200 or more of the boards in stock, maybe it's time to have a sale.

    Lighting season in the Northern hemi died down a while back, but the Southern Hemi is about ready to launch into night ride season.

  15. #15
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    Beamshots...I measured the shed from the lights with a tape...50 feet 6 inches:

    Control


    Magicshine


    My own P7 creation


    Both together



    So the MS has more flood with a larger hot spot and a warmer emitter. The Homebrew has a cooler tint, tighter/slightly brighter hot spot, and less flood. I should switch these around and run the Homebrew on the helmet...but honestly...both will be adequate in either situation.


    I'd like to take this time to show y'all a little light that I picked up recently. It's a Trustfire TR-1200. It has 5x Cree XR-E Q5's and will run on 3 RCR123a's, 2x18500's, 2x18650's, or 3x18650's in series (just add extensions for whatever battery combo):



    This 50' beamshot doesn't do it justice b/c this light can throw a beam a couple of football fields. 50 feet is just rediculous for it Notice the blue'ish streak on the right side of the picture...that's all LED flame.
    Last edited by chelboed; 04-03-2010 at 08:37 PM.

  16. #16
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    What is the build quality like on the Trustfire TR-1200? With a bit of Modification (remote battery) do you think it would make a good helmet mounted light? Or is the torch head to heavy?

  17. #17
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    Funny that you mention it...this is the original reason I bought it. The head is quite heavy. The reflector and heatsink are both for the most part, solid. It would be quite annoying on the helmet. The body of the lamp head that the insert seats in is also fairly thick aluminum. I'm pleased with the construction of this "budget light". It's pretty burly for a DX'er.


    The real problem however is the practicality of the beam itself. It's just too tight. If you're riding on the road...it may be alright...you will probably end up getting pummeled by random motorists due to the intense brightness. For trail riding...it's just too tight. Decent spill, but the hot spot is so tight that you'd have to have it pointed 40-50 feet in front of you to have a broad enough beam.

    If you want a 5xQ5 setup for the bike...it's probably best to either try building one out of rectangular box-channel and set the Q5's all up in-line...or try to find some Carlco optics to broaden the beam a bit.



    If you disagree with me regarding the beam width and still wanna try it...you can buy just the drop-in in either Q5 or R2 now in the low $30's. You could use a thinner host to drop it into saving weight. I will get out to the trail soon and do a more practical beamshot for you that doesn't involve a light colored shed reflecting back at you to skew percieved intensity of the light. It's freakin' bright for $45...but as stated in another thread...high powered LED setups should have beamshots directed at more neutral things.

    Stay tuned...

  18. #18
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    Here's a link to the r2 drop-in:

    http://www.dealextreme.com/details.dx/sku.35242

    over 3 oz just for that.

  19. #19
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    Unfortunately I don’t have the spare time to manufacture something from scratch so thought modifying something might be a quicker option. Is there scope to machine down some of the components to lose some weight?

    When you mention "or try to find some Carlco optics to broaden the beam a bit" do you mean for the TR-1200 or just in general.
    Last edited by searchtime; 04-08-2010 at 02:57 PM.

  20. #20
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    I meant if you didn't want to build a linear shaped setup...you could buy some aluminum round stock...thermal epoxy 5xQ5's to it...put some aluminum pipe around the round stock...add Optics...build a power supply...light up the night.

  21. #21
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    I think it'd be much easier for you to just grab two MTE P7's, two Weaver scope rings, one Aluminum I-beam.

    Take one of the flat bars off the I-Beam leaving you with an upside-down "T" beam. Screw the two scope rings to the vertical leg. Trim to design. Mount both P7's on the rings and carry 4 spare batteries. (two hours of runtime from a dual P7 setup) very easy.

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