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Thread: Big square plate with 70 cree LEDs

  1. #1

    Default Big square plate with 70 cree LEDs

    I have a big plate, maybe 6 or 7 inches square. It has 70 LEDs with room for about double that. It came from a street lamp which was rated 13000 lumens at 96 watts. No idea if it actually reaches that at that wattage but I do know the driver is rated for a little over .5 amps and 375 VDC max. I also know that it is BRIGHT. The driver works on 120VAC and it would be ok for a plug in lamp once a reflector, housing, etc is fabricated for it, but I'm curious if it can be made into something battery powered for portability. Obviously, nobody really needs 13k lumens in a flashlight, but I also can't see much meed for a work light that bright. One wrong turn of the head and you're not going to see much for a while. Anyone have any ideas on what could drive this thing using batteries? I'm hoping to use 18650s but I'm open to suggestions.

  2. #2

    Default Re: Big square plate with 70 cree LEDs

    I'd think it might be safer to use a 12 volt SLA connected to an inverter to power it, although I doubt it would last long. Maybe you could try using a power tool battery pack but again, I don't think it would last long in actual use. It seems that they may be operating at around 5 volts so maybe you could find a way of driving them but usually those set ups are configured with the leds in some sort of arrangement (multiple pairs in series or something like that) to deal with higher voltages.

  3. #3

    Default Re: Big square plate with 70 cree LEDs

    This thing is definitely series all the way through. It looks like the spots that don't have LEDs might be on a parallel circuit, but there's nothing there. You can just make out the circuits under the white film that cree put over the plate. They look like XP-G LEDs and the light is about as white as it gets, so I'm assuming around 5000k. That would make these 3W 2.7V LEDs if my info is correct. Likely under driven to reduce heat, even though the back of the plate is bare aluminum and just waiting for a big heat sink. Another problem is the roughly 15mm spacing, which could make it difficult to find reflectors that will fit. What is the preferred image hosting site and image size for this forum? I'll post up some pics of the board and driver. Maybe I can get the tracing to show up. Dunno if that'll help though.

  4. #4
    archimedes's Avatar
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    Default Re: Big square plate with 70 cree LEDs

    Quote Originally Posted by Krazymonkeys View Post
    .... What is the preferred image hosting site and image size for this forum? ....
    There is no "preferred" image host here, although many use Imgur (among others) ; the requested max photo size is 800x800.
    ... is the archimedes peak

  5. #5

    Default Re: Big square plate with 70 cree LEDs

    Here is a pic of the driver

    And here is the board

    I dunno if it's sized correctly, so I just posted the link. I can't take a pic in anything close to being as small as 800x600 on my phone and I didn't see any resizing options on imgur. I really hate image hosting. I'm not really a picture taking sort of guy. That's my wife and daughter's thing lol.

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