What amp fuse for LED light bar?

[Blake]

I've read that if you don't have a big enough fuse in the switch, a light bar won't be as bright as it should.

What size fuse should I use for a 50W 11" LED light bar?

 

[JMichael]

5 amps (amps = watts / volts) Based on my understanding of electronics, that's nonsense to think the size of the fuse can control the brightness of a light, as long as you haven't blown the fuse that is.

 

[GTS225]

Yes, Blake, I'd be interested in knowing where you read that.
A switch with too small of an electrical capacity can limit amperage, and wire that's too small can also limit amperage, with both cases resulting in voltage drop to the load, and wires or switches that run hot. A fuse, even if too small, will blow rather than limit current flow in the manner you're describing. Fuses are a yes or no protective device.

Roger

 

[DaleH]

5 amps (amps = watts / volts) Based on my understanding of electronics, that's nonsense to think the size of the fuse can control the brightness of a light, as long as you haven't blown the fuse that is.

Yup, that's it - 50 watts / 12.6 nominal DC voltage = 3.9 amps. I too would throw in a 5, as doubt you could find a 4. Recall fuses are there to protect the wiring from burning ...
not so much as to protect the device/load.