Light bar wiring

[NFG]

Hi

 

Firstly you need to understand that power in Watts = Amps x Volts - so if you have 120Watts of light they will draw 10 Amps from a 12 volt (nominal) battery

 

ie: 120W = 10A x 12V.

 

So you need to first calculate the current your lights will draw, if it is significant then you need to allow sufficient cable capacity, fusing & a relay to handle it.

 

In my above example of 10 Amps draw for a 120 W light, I would double the current carrying capacity of the cable to 20 Amps - or more perhaps 30Amp & use a 15 Amp fuse to protect the cable run.

 

The fuse must be rated accordingly to permit it to blow before the cable melts & causes a fire.

 

I would use a relay to switch the current again rated at the same of the cable 20Amp maybe 30Amp, The relay switching circuit carries minimal current, perhaps a few milliamps, so that is not significant & you could spur it from a separate fused circuit.

 

The main supply, i would take from the battery, via a suitably rated fuse, switched through the relay.

 

Thats how I would implement it

 

N

[7610]

Precisely.