Ws2801 led module - correct fuse

Discussion in 'RGB Lights - Intelligent Pixels and 3-Channel RGB' started by moogle, Nov 12, 2012.

  1. moogle

    moogle New Elf

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    Hi there,

    Just want some confirmation ive worked this out right. Im making an
    Led matrix. 49 modules per panel. And a total of 8 panels altogether

    Power supplies have three outfeed wires. So im going to hook up 65ish
    Leds to each 12v output lead.

    They are .96w a module. Do i do .96x66 And then divide by 12 to get 5.6 amps.
    So i need abit over 5.6A fuse for each output from the power supply?

    Should i also fuse the main powersupply infeed?

    Thanks for your help people. :)
     
  2. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

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    The purpose for the fuse is to protect the wire used from getting hot and burning up due to high currents that can be produced from a short, it also protects the controller board from taking on too much load and burning up. So the rating of your fuse should match the cabling used. Generally a 7.5 amp fuse will do the job well for your needs. It also depends on the controller type used. the ECG P12R, ecg-pixad8 and E681/2 already have fused output protection so if you are using those then no need to add any fuses.

    The main power supply is already protected by the power circuit its plugged into so no need to add a fuse here.

    What i would like to know what you are actually using to create this as it doesnt sound like the standard lighting that is used like strip or strings.
     
  3. OP
    OP
    moogle

    moogle New Elf

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    Im using ws2801 modules 20pcs per string from ray wu.

    Using the new p2 so injecting power with 2 x 250w power supplies.

    The 1.5mm v90 cable i used is rated to 19 amps up to 5metres.
    So all is good there.

    Would a 10a fuse be too big dont want led strings to be damaged if
    Anything happens :/
     
  4. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

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    10 amp should be fine but a 7.5 amp would be better, remember the fuse isnt there to actually protect the pixels, its to protect the wiring circuit from being overloaded due to a short, the actual LED string cable is normally around the 22 guage so thats around 4 amps tops, but the cable itself will act as a resistive load under short conditions and depending on how far away the short is may not actually blow the fuse.

    In fact i dont have any fuse protection except for that on the P12R outputs because any major short would put the power supply into an overload condition and shut down and any minor pixel short may not actaully blow a fuse and because you are using a ECG-P2 controller then the load is not going through the controller so the fuse is not protecting the board. But it is best and reccomended practice to add fuse protection
     

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