Thinking of a dual P7, or should I go with MC-E ?- Mtbr.com
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  1. #1
    I like bloody ankles
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    Thinking of a dual P7, or should I go with MC-E ?

    I found this forum and got hooked a few months back, or maybe I should say it like this:

    "Hello, my name is Damon, and I'm a DIY-aholic"

    So far I've made three lights - a single and double R2 for the helmet based on Dinotte style, and triple R2 with achesalot housing. I've been very satisifed with the results and the hobby aspects of the process, and now I want to venture into a multi-die emitter build.

    I also have an MTE P7 2-mode flashight and can't deny the quality of the beam pattern and output from a single board, but I haven't seen anyone do a double P7 build. Why not - is it thermal issues, high current rates, poor optics choices ? It seems everyone is focusing on the MC-E for the multi board builds.

    I was thinking an achesalot style housing with lots of cooling fins, similar to what he did with the dual MC-E. I (think) that could be driven two P7 in series at anywhere from 2400-2800ma and with a Vf of under 8v, and this would allow fairly inexpensive drivers and battery configurations.

    Is this a workable config, or am I missing something that you all have tested and didn't work out ?

  2. #2
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    MC-E you can focus better as its smaller and for the same lumens it puts more light forward as P7's aren't really designed for torches more of something to light a room up I think.

    P7's whiter though which I prefer.

    More Optics available for MC-E aswell.

  3. #3
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    Here is a triple P7 light posted by KridX, should give you some ideas.
    http://forums.mtbr.com/showthread.php?t=490988

  4. #4
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    You also get more driver and battery options with the MCE as you can run it in 4s, 2s2p or 4p so can adapt the Vf to suit what you already have.

  5. #5
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    Unless you are building custom drivers or sandwiching boards there are not many drivers that I am aware of that will drive at 2.8.

  6. #6
    I like bloody ankles
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    Quote Originally Posted by yetibetty
    Here is a triple P7 light posted by KridX, should give you some ideas.
    http://forums.mtbr.com/showthread.php?t=490988
    Wow, that's a crazy and beautiful build, but far beyond what I'm going to achieve with my bandsaw, belt sander, and hand tools. Maybe that does tell me what sort of thermal management is needed though, and I think that's a few steps beyond a square tube build

    Quote Originally Posted by zen bicycle
    Unless you are building custom drivers or sandwiching boards there are not many drivers that I am aware of that will drive at 2.8.
    I wouldn't mind a sandwich in this case, or I think that KD has a board that could do the job, although maybe quality is a question. I already have 14.4 and 11.1 battery packs, so it seems that the optics are the outstanding issue, assuming I can keep the light cool enough - never mind, I'll just keep moving fast

    Or maybe I should just go the MC-E route like most folks have......

  7. #7
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    If you want to go mutli-die don't forget Osram, they produce some great stuff.

    Hard to get hold of and a bit bespoke but very nice. http://www.osram-os.com/osram_os/EN/...ily/index.html

    There are some Ostar builds posted on here if you have a search.

    I want to have a go at building a light with the 4 die Ostar but I can only get hold of the 6 die version.

    This link maybe better: http://catalog.osram-os.com/catalogu...t=showBookmark

    Edit; found you an Ostar build http://forums.mtbr.com/showthread.ph...ighlight=Ostar and yes I know it can't be done with a hacksaw and sandpaper but it could keep you awake at night with Ideas
    Last edited by yetibetty; 06-06-2009 at 09:56 PM.

  8. #8
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    Quote Originally Posted by dsjc
    ....I was thinking an achesalot style housing with lots of cooling fins, similar to what he did with the dual MC-E. I (think) that could be driven two P7 in series at anywhere from 2400-2800ma and with a Vf of under 8v, and this would allow fairly inexpensive drivers and battery configurations.

    Is this a workable config, or am I missing something that you all have tested and didn't work out ?
    Maybe a better idea would be to run a duel P-7 setup using two sets of the Sandwiched 1400ma drivers that EL34 has talked about. I can't see why that wouldn't work but you would have to have two separate switches. One of the switches would be a simple on/off and the other would be the 3-way that EL34 has been using ( on/off, low, high, ). In essence this would give you three levels of light, low ( 400lm), mid-level ( 700lm), high dual ( 1400lm ). It just means you have to hit the other switch when you want super high. I don't see a problem with that as long as you have a battery that can handle a ~ 6A current drain.
    Last edited by Cat-man-do; 06-07-2009 at 03:46 PM.

  9. #9
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    Normal 18650's work upto @1.8Ah's, so you'll need 3 - 4 18650's to drive 2 P7's I believe.

    Cat-Man, should ( fingers crossed ) have that Fraen Reflector fitted to our first MC-E torch, see if we can get a beam quality, output and range boost for 4

  10. #10
    I like bloody ankles
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    Quote Originally Posted by Cat-man-do
    Maybe a better idea would be to run a duel P-7 setup using two sets of the Sandwiched 1400ma drivers that EL34 has talked about. I can't see why that wouldn't work but you would have to have two separate switches. One of the switches would be a simple on/off and the other would be the 3-way that EL34 has been using ( on/off, low, high, ). In essence this would give you three levels of light, low ( 400lm), mid-level ( 700lm), high dual ( 1400lm ). It just means you have to hit the other switch when you want super high. I don't see a problem with that as long as you have a battery that can handle a ~ 6A current drain.
    You're right about running dual drivers, I've seen what EL34 is doing and also considered something like this:

    http://www.kaidomain.com/ProductDeta...ProductId=1866

    I could run two of these, with an on/off switch inline and a momentary switch on the housing to control both drivers in parallel ??

    I haven't seen a driver that will do 3a at the Vf of two P7's, it would be sweet if one existed !

    And here's a calculation question. Would I really be drawing 6a over the 2 emitters if I'm running a buck circuit ? If direct drive, I would understand the current at 6a, but since we're bucking from 12-16v down to < 8v, wouldn't that reduce the current drawn from the pack ?

  11. #11
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    Quote Originally Posted by dsjc
    You're right about running dual drivers, I've seen what EL34 is doing and also considered something like this:

    http://www.kaidomain.com/ProductDeta...ProductId=1866

    I could run two of these, with an on/off switch inline and a momentary switch on the housing to control both drivers in parallel ??

    I haven't seen a driver that will do 3a at the Vf of two P7's, it would be sweet if one existed !

    And here's a calculation question. Would I really be drawing 6a over the 2 emitters if I'm running a buck circuit ? If direct drive, I would understand the current at 6a, but since we're bucking from 12-16v down to < 8v, wouldn't that reduce the current drawn from the pack ?
    Hmm...I've looked at those KD drivers before and looked at the stats for running at different voltages. KD recommends not running it over 12v. I think that is because it makes the driver work harder. I think your right though, the table they give for different voltages also shows the input current draw. If you were running say a 4800mah 7.2volt Li-ion battery (per batteryspace ) their battery is rated at 5A max. According to the KD specs. one 7.2volt battery would output 1.6A with the light on high. Two drivers in parallel would be double that ( 3.2A ). That is well within specifications for the BSpace battery. Just make sure you heat sink the drivers REAL GOOD. Now about running the drivers with one parallel momentary switch...I've often wondered if that would work. As long as both drivers sense the pulse and change to the same output level at the same time you have no problems. If they don't, then you have problems. I say give it a shot and see what happens.. Just have another momentary switch on stand-by just in case it doesn't work. Oh yeah, I was probably wrong about what the EL34 drivers would draw as well. Maybe send him a PM and ask what current is drawn from the battery with his 2800ma sandwich driver set-up. Post up if you get an answer.

  12. #12
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    I might have found an answer to the 1 vs 2 driver question. Check this out - 1 driver board powering multiple P7's at full current by creative circuit design.

    http://www.candlepowerforums.com/vb/...d.php?t=201392

    In this case, using the AMC chips we just need as many parallel 18650's as we have emitters, no more buck circuit. This may not be my preference since I wouldn't use existing battery packs, but it looks to be an option.

  13. #13
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    Got your PM dsjc.

    On the dual 1400ma board setup I use, I am measuring the actual battery current by interupting the battery negative and sending the current flow through a multimeter that is set on DC amps.

    I am using 3.6 volts battery packs
    3 and 4 x 18650 battery packs - all soldered in parallel

    I use this tool to do that - more info here on that.
    https://www.el34world.com/Misc/bike/BikesLights33.htm



    The SSC P7's I am using are the ones DX sells

  14. #14
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    Quote Originally Posted by dsjc
    I might have found an answer to the 1 vs 2 driver question. Check this out - 1 driver board powering multiple P7's at full current by creative circuit design.

    http://www.candlepowerforums.com/vb/...d.php?t=201392

    In this case, using the AMC chips we just need as many parallel 18650's as we have emitters, no more buck circuit. This may not be my preference since I wouldn't use existing battery packs, but it looks to be an option.
    The only issue with running 7135 boards like this is the heat generated. In order for the 7135 to work there has to be some voltage across it. They need a minimum of .120 volts to get to full current. Since they are linear regulators the heat is simply (voltage across regulator) * current. As you run more cells and more LED's you get more heat. It should be manageable with 2 for sure, three could be pushing it, and four might be too much. Since the boards are designed for a single cell you just have to plan for the extra heat.

    I am considering this type of circuit as it sure is simple.

  15. #15
    Carbon8er
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    Yes, the 7135 boards make it really simple without wasting a bunch of battery current by having to regulate a higher voltage down.

    That is always just wasted as heat.

    Of course, I am sure the 7135 boards have their draw backs also.

  16. #16
    I like bloody ankles
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    Another option has been presented to me by the CPF crowd - a Shark Buck 3amp can be used and the optional Remora to provide the UI settings, or simple dimming with a pot. Definitely a pricier approach, but I've had nothing but good luck from these guys products.

    http://theledguy.chainreactionweb.co...oducts_id=1244

    So this is good news, I have at least two wrokable options for the electronics, and I'm confident I can provide thermal management (must keep pedaling.)

    So what's out there for optics ? Anything decent that will fit in a 21.6mm ID ?

  17. #17
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    Quote Originally Posted by dsjc
    I might have found an answer to the 1 vs 2 driver question. Check this out - 1 driver board powering multiple P7's at full current by creative circuit design.

    http://www.candlepowerforums.com/vb/...d.php?t=201392

    In this case, using the AMC chips we just need as many parallel 18650's as we have emitters, no more buck circuit. This may not be my preference since I wouldn't use existing battery packs, but it looks to be an option.
    A while back I remember seeing something on linear current regulators. They can supply the current but usually within a defined set voltage range. The people on CPF that figured out how to power 3 x P-7 with this set-up deserve a metal. I wonder if it could be moded to work with just two P-7. Anyway, much of what they were talking about eluded me and I'm still not sure how they control the dimming of the LED's. Just make sure if you try this to have a lot of extra boards on hand just in case you do something wrong. Better yet, maybe e-mail that fellow ( Download ) and ask him all the questions before beginning.

  18. #18
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    Hi dsjc, have you looked at taskled drivers?

    The hipflex has some clever thermal management protection and battery over-discharge protection built in. It is also more efficient and cheaper than a Shark with remora.

    Optics I'm not sure about, but I think that Ledil do a range of reflectors for P7...

    You might also need to buy some new sun glasses!!

  19. #19
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    Quote Originally Posted by bumphumper
    Hi dsjc, have you looked at taskled drivers?

    The hipflex has some clever thermal management protection and battery over-discharge protection built in. It is also more efficient and cheaper than a Shark with remora.

    Optics I'm not sure about, but I think that Ledil do a range of reflectors for P7...

    You might also need to buy some new sun glasses!!
    I know taskled has some good stuff, but hadn't been able to view the details since the site was down. I see the site is back up now, thanks for that reminder !

    I'll check Ledil for the optics. I really like their square CRS line and hopefully I'll find something similar for the P7's.

    new theme song - I wear my sunglasses at night....

  20. #20
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    Quote Originally Posted by bumphumper

    Optics I'm not sure about, but I think that Ledil do a range of reflectors for P7...
    You're right, Ledil does have the Boom series reflectors that I could shave 1mm off and fit. Based on MC-E feedback I'd probably go with the S, the tightest angle.

    So this might be coming together - achesalot style double case with extra cooling fins, double P7's, 3a shark buck with pot, Ledil boom reflectors, 14.4v 4400mah pack. I might have a plan !

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