DX SKU 15946 P7 conversion- Mtbr.com
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  1. #1
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    DX SKU 15946 P7 conversion



    I took one of the DX SKU 15946 empty flashlight shells and am in the process of converting it for 1.4amp/2.8amp P7 operation.

    This item is a great deal for $11.50.
    Not too crazy about the reflector that came with it so I changed it out to another one I like better.

    I have the shell machined down on my lathe.
    I still have to do the internal electronics.



    Here's a couple shots of the shell put back together and sitting on a Marwi mount.




    I have more info here with bigger pic's
    I'll add more to this page when I get the electronics installed.
    https://www.el34world.com/Misc/bike/BikesLights34.htm

    see ya
    Doug

  2. #2
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    The DX flashlights are an awesome source for cheap and nice looking housings. Do you think it will have enough area to dissipate the heat from a P7? Also, what diameter of reflector fits the housing?

  3. #3
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    A 37mm diameter reflector fits this housing.

    It comes with a short stubby 37mm reflector that creates a fairly wide angle beam pattern.
    If you order the DX 14599 35mm diameter reflector, you will get the wrong 37mm reflector.

    This 37mm reflector fits into this shell.
    DX keeps shipping the wrong reflectors and they know they are doing it.

    I have a note on my web page about moving the mounting ring forward next time and leaving the fins intact.

    Have to see how it dissipates heat as it is.

    One thing about the DX flashlights compared to my home made shells.
    The DX lights do not shed the heat as fast as a thinner shell does.
    The DX lights have quite a bit of mass which tends to heat up and hold onto the heat.
    It's not a problem in winter on a bike with moving air, but standing still on 2.8amps could be a problem.

    I would click the light down to 1.4amps if I had to hold still with no air moving over the light.

  4. #4
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    Quote Originally Posted by El34
    ...I have more info here with bigger pic's
    I'll add more to this page when I get the electronics installed.
    http://www.el34world.com/Misc/bike/BikesLights34.htm

    see ya
    Doug
    After looking at your blog I got think'in....You think it's possible to sandwich a 1400ma driver and a 1000ma driver? I would think it would give you some more options if you didn't want to run all out at 2.8a. 2.4amp would still be bright and perhaps a little more efficient. You could also chose which to run as your low...1 or 1.4A. I wonder how many lumens would come out a 1A?

  5. #5
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    Very nice job with the conversion! I like how you retained most of the original parts too. Are you planning to route the cable out the back through the button hole or somewhere else?

    I have used a KD multi-mode 1000ma driver (3215) with a DX 7135 1400ma driver (plus another half board with one more 7135 to get to 2.8amps. I don't use that light much anymore, but it worked with modes and made a neat sandwich, though it was a triple stack so it may be too tall for this light.

    EDIT: I just searched for the KD sku 3215 and it looks like they may no longer have it. I think that DX 6190 would also work for the mode driver board.
    Last edited by HuffyPuffy; 06-02-2009 at 02:43 PM.

  6. #6
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    Hmm, I guess you could use different boards for different current combo's.

    The way I get 1.4 amps is by just connecting the negative of one of the 1.4 amp boards.

    Then 2.8 amps happens when the switch connects the negatives of both 1.4 amps boards.

    In other words, a 1000ma board would give you 1 amp if you turned it on first, then both boards turned on would only give you 2.4 amps total.

    I don't have a direct drive mode because on a full 4x18650 battery pack, I have measured 3.2 amps in direct drive mode.

    I gotta tell you. 1.4 amps is nice because it is using half the battery current, but the amount of light is still quite bright. I use the 1.4 amp setting for long uphill climbs and then 2.8 amps for the screaming downhills.

    Actually I use, one P7 on 1.4 amps on the uphills (you only need a little bit of light on a climb) and then two P7 lights set on 2.8 amps for the downhills.

    You probably already saw this diagram on my wb site, but just in case.
    This is how the two 1.4amp boards work with the modified switch.

  7. #7
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    Are you planning to route the cable out the back through the button hole or somewhere else?
    I haven't got that part worked out yet, but there is not room for an out the back cable.
    I have an idea, hope it works out.

  8. #8
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    Ok, I figured out how to get a cord into the case.

    I had to notch a circuit board so you can have all the guts outside and then push/pull the whole assembly into the tail cap. The circuit board must be able to slide past the cord in order to get it all in the tail cap.

    When I first got this flashlight carcass, I was looking at it and thinking this would be pretty simple to make P7's out of it.

    Wrong.

    It is a bunch of work and I don't think it is going to run anywhere near as cool as some of my scratch built lights.

    I'll have it running tomorrow and then test it.




  9. #9
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    Quote Originally Posted by El34
    ...I gotta tell you. 1.4 amps is nice because it is using half the battery current, but the amount of light is still quite bright. I use the 1.4 amp setting for long uphill climbs and then 2.8 amps for the screaming downhills...]
    El34, how bright would you say it is at 1.4A ? 350-400lm? I'm trying to decide whither to do what you've done or just try to mod the new D/X P-7 bike light.

  10. #10
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    Hmm, hard for me to say, don't really know how to compare it in Lumens.

    But I would say that it appears to my eye to be about 60-70% of the full 2.8 amp setting.

    The LED current and light output don't seem work on a linear scale.

    I may be able to get a beam shot comparison tomorrow night.

  11. #11
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    The cable routing looks good, too bad it is a difficult job to cram it all in there (but making stuff small seems to come with that problem). I would bet that running at 1.4amps would still make it a really nice light to use on the bars and it would probably be OK with enough airflow.

  12. #12
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    Actually, it was not too bad to get that cable in place after all.

    I took it apart a few times during the final electronics boards installation and it was fairly easy after I got the hang of it. The rubber grommet makes a nice seal, but you could always add some silicon for a better seal.

    The two body halfs are held together by a tiny screw on the belly of the light.

    It is actually a pretty cool light, but I think you have to watch out for the front bezel. It could rip some flesh if you are not carefull.

    I added some more pics and info to the web page here.
    https://www.el34world.com/Misc/bike/BikesLights34.htm

    Here it is all done and running on 2.8 amps.






  13. #13
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    El34

    Nice work. I've been thinking about doing something like this for a while but don't really have the tools to do so. My plan was a little different and probably a bit easier. I thought I could cut the battery tube a little behind the light head on a sku.12060. Then machine an end cap for the light head and an end cap for the battery holder. Drill a hole for a wire and attach battery contacts then bond the end caps in place.

    OK it doesn't give you a larger battery, or a switch on the head, but for morning road riding all i need is about 45 min of light, and this form fits bars better with separate bttery, light head units. I don't have a lathe and its pretty hard to find something that will work as an end cap without machining.

    Wish some one were selling them.

    Anyways, just a thought.

    M

  14. #14
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    Yeah, the machining part is the part that always gets in the way.

    It's hard to find a carcass that does not require too much work to make a short light.
    maybe that new P7 DX bike light would work for your needs?

    Hard to beat $79 for a complete kit
    http://www.dealextreme.com/details.dx/sku.25149

  15. #15
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    EL34, hard to tell from the photos...Is that light of yours able to tilt ( up/down ) on the off-set Marwi mount?

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