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off-road lights and fuses

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bajaviking, Apr 18, 2002.

  1. bajaviking

    bajaviking 1/2 ton status

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    Just installed my KC Hiliter 150 watt offroad lights and I was wondering what size fuse I should use and also if the fuse goes on the negative or the positive side.
     
  2. txbartman

    txbartman 1/2 ton status

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    Fuse always goes on the positive side. If your light were to short due to a corroded or cut wire, a fuse on the NEG side would be of no use.

    I would also recommend using a circuit breaker versus a fuse. If a fuse blows on a light, the light won't come back on until you replace the fuse. A circuit breaker will automatically reset itself. Hence, your light will come back on once the problem is alleviated. For instance, you get something wet and causes a short. The circuit breaker will reset after it has dried enough to stop the short. You will get your lights back.

    On my 130W lights, I use 30A circuit breakers for a pair of lights, 25A for 100W pairs.
     
  3. Panther

    Panther 1/2 ton status

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    Check it out:
    <a target="_blank" href=http://www.diynet.com/DIY/article/0,2058,3404,00.html>http://www.diynet.com/DIY/article/0,2058,3404,00.html</a>
     
  4. bajaviking

    bajaviking 1/2 ton status

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    Great, this is what I needed to to know. Thank you for the reply!
     
  5. Sandman

    Sandman 3/4 ton status Author

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    To figure out how many amps you will be pulling, Divide the total wattage by the voltage and then add 10% for the fuse or breaker. For example: If you are running two 100 Watt lights and your alternator puts out 13.4 Volts then you will be pulling 14.9 amps (200/13.4). Or you could figure it at 12 volts with the engine off and get 16.67 amps (200/12). So in your case you didnt say how many lights you installed so I will assume two ( yeah I know about ass-u-me), so worst case is 300/12 which is 25 amps. Add 10 percent for voltage spiking and you get 27.5 amps. Looks like you could get away with a 30 amp fuse or breaker. Let me know how it works.
     
  6. BurbinOR

    BurbinOR 3/4 ton status

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    Great advice here..........one more. Use a relay in addition to a circuit breaker/fuse.
     

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