I see this question asked a lot.. What size fuse do I need for my lights.. This is how to figure it out.

[scotman623]

Easiest way to figure out what size fuse you need for adding lights is simple using this method. Does not matter if you are running 1 light or 4 together.. Take the TOTAL wattage from all the lights your hooking up and divide it by Volts will equal the amps with is the fuse size you will need to run your aftermarket lights.. So watts Divided by volts (most batteries are 12.5-13.5 volts =amps- fuse size.. I always use 12.5 to figure out fuse size.. Hopefully this helps some of you out on installing your lights..

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[da_jokker]

Just to add, especially since advertised wattage isn't necessarily accurate.... Another easy way is to take a multimeter (can be had for $10) and use it to test the actual amp draw as well.

 

[KABQ]

Just to add, especially since advertised wattage isn't necessarily accurate.... Another easy way is to take a multimeter (can be had for $10) and use it to test the actual amp draw as well.

^^^This. Learning to use a multimeter is a super valuable skill. Buy the cheapest Harbor Freight one to start so it won't matter if you blow it up. There are a ton of great videos (and some terrible ones) demonstrating how to hook it up properly depending on what you're trying to measure.

That said, in this case advertised wattage is usually high, so using that number is relatively safe.

 

[mj63]

The right answer is to size the fuse to protect the wiring (i.e. fuse burns out before wiring fails), and size the wiring to handle the expected load plus a little.

 

[da_jokker]

The right answer is to size the fuse to protect the wiring (i.e. fuse burns out before wiring fails), and size the wiring to handle the expected load plus a little.

So true...and a great point. A 30 amp fuse won't help you if you put it on a 10 amp wire... You'll just burn down your Bronco!

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