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  1. #1
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    which cutter kit will suit me best??

    ive decied im going to attempt a cutter kit diy build but im not sure which cutter kit would be best to use.

    im going to use a lumicycles housing and im only bothered about being able to turn it on or off (i think??)and being as bright as possible.

    which kit would be best the fatman or bflex ?? is there much differentbetween the two??

    also as i will have a bare lumi housing with no power input connection what an people recommend i use??

    im going for the 10 aa2800mh battery thing if it helps??

    what will the run time be using these.

    any infor or guidance will be most appriceated as i dont want to bollox them up!!
    cheers
    steve

  2. #2
    Spanish biker
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    Hi, Steve.

    The difference between fatman and bflex are that the fatman are a bost circuit, this need minus volts that bflex circuit already that this need 3,7 volts for led and 1,1 volt for the bflex, if you use 10 aa batteries, then you could use better the bflex.

    Greetings - Saludos

    msxtr
    Warning!!! my english is very very bad, sorry.

    Easy DIY led light1
    Easy DIY led light2

    The Beast!!!

  3. #3
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    Hello bikingbarney

  4. #4
    Singletrack Daydreamer
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    A fatman is a boost puck (steps voltage up if you don't have enough), a bflex is a more standard driver, needing a greater voltage going in than used by the LEDs in series.

    I'm assuming you're using rechargable AA batteries, likely nicads, which put out 1.2v each. 1.2x10 = 12.0v output
    I'm assuming you're using cree 7090 XR-E lamps, which draw 3.6 maximum = 10.8v.
    The Fatman can take from 3-12v and boost it up to 16v (drive up to 4 LEDs), but you'll have only one setting: 1000ma, which is going to produce a lot of heat.
    The B-flex needs 1.5v more than your draw, so fully charged, you're right at the upper limit and you'll see some dimming from early on. However, you'll have dimming capabilities from 350ma-1000ma.

    Frankly, the problem I see is your battery. Reconsider using AA batteries and think about buying a 13.7-14.8v battery and then go with the Bflex. I'd be willing to drive Crees at 700ma all day long, but driving them at 1000ma constantly seems like you're inviting a meltdown if you don't have your cooling dialed in.

  5. #5
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    Quote Originally Posted by rockymtnway
    A fatman is a boost puck (steps voltage up if you don't have enough), a bflex is a more standard driver, needing a greater voltage going in than used by the LEDs in series.

    I'm assuming you're using rechargable AA batteries, likely nicads, which put out 1.2v each. 1.2x10 = 12.0v output
    I'm assuming you're using cree 7090 XR-E lamps, which draw 3.6 maximum = 10.8v.
    The Fatman can take from 3-12v and boost it up to 16v (drive up to 4 LEDs), but you'll have only one setting: 1000ma, which is going to produce a lot of heat.
    The B-flex needs 1.5v more than your draw, so fully charged, you're right at the upper limit and you'll see some dimming from early on. However, you'll have dimming capabilities from 350ma-1000ma.

    Frankly, the problem I see is your battery. Reconsider using AA batteries and think about buying a 13.7-14.8v battery and then go with the Bflex. I'd be willing to drive Crees at 700ma all day long, but driving them at 1000ma constantly seems like you're inviting a meltdown if you don't have your cooling dialed in.

    Dont mean to confuse but we expect to get the Maxflex(boost driver) next week with a UIB2 inetrface. so best of both worlds

    Cheers
    Mark
    Cutter Electronics

  6. #6
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    im now going to use 12 x 2800mah batteries !!
    im sure this will be enough to run the mr11 cree kit at 700ma for a while ???? wont it

  7. #7
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    The maths goes something like this

    12 x 1.2 volt cells x 2.8 amp hours = 40.32 watt hours in the batteries

    3 x 3.5 volt led's at 0.7 amps = 7.35 watts an hour draw

    40.32 divided by 7.35 = about 5.5 hours light

    running at 1000ma it will give you about 4 hours

    I haven't accounted for losses in the bflex, probably worth working on a 10 to 20 percent loss

    Hope this helps

    Ian

  8. #8
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    Quote Originally Posted by rockymtnway
    The Fatman can take from 3-12v and boost it up to 16v (drive up to 4 LEDs), but you'll have only one setting: 1000ma
    No, as standard you'll have one setting at whatever power you want - you can set this at 700mA, which I'd suggest is more sensible than 1000mA if you are bothered about runtime.

    You can of course also run switched resistors with a Fatman for different levels - see My new design is finished for how somebody is doing this.

  9. #9
    Singletrack Daydreamer
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    Good to know, thanks Chris! It's sweet that you can use switched resistors. My current project is using a 3-way switch with two micro-dash pots so I can fine tune if I need to, but it uses a BuckPuck. I have a Fatman on the way from Australia as we speak, so it's good to know I have options.

  10. #10
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    I'm also looking at the Cutter kits, but not sure which to get. I'm upgrading an old Niterider TrailRat system (6V, 4500mAh battery pack, MR11 housing). Usage is evening commuting, not offroad (have another helmet mount system for that). The reason for the upgrade is burn time - I hate having to charge the battery every night (I forget frequently).

    I think the Cree XR-E 1000 kit (single XR-E, 8* optic, 1Amp Luxdrive BuckPuck) is probably the best bet. It might not give as much light as the halogen, but the burn time should be roughly doubled.

    The math:
    5 x 1.2 volt cells x 4.5 amp hours = 27 watt hours in the batteries

    1 x 3.5 volt led x 1 amp = 3.5 watts an hour draw

    27 divided by 3.5 = about 7.7 hours light theoretical - inefficiency losses = 5 hours or so?

    Currently, with the halogen setup, I'm getting 2 to 2.5 hours.

    I think the LED kit should still be somewhere around 200lumens, which should be plenty for night-time street use. I think?

    Does this all sound right? Will I be able to run this kit without melting it? Am I missing sometime?

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