Upfitter #2 BD S8 30 Fuse Blowing

[The Car Stereo Company]

anytime you reach 75-80% of a circuits maximum, you need to use a relay. standard automotive relays are rated for 30-40amps. the reason behind this rule is that heat plays a role in electricity. ever see a circuit breaker under the hood of a car for an amplifier? even though its rated at 150amp it will pop sooner because of the fact of the heat. same situation here. the engine bay gets hot. heat is the byproduct of electricity. the more heat, the less electricity. so at 12 amps you are >75% of the circuits max. and being that its dc current, you will generate a fair amount of heat in the wire. plus the heat from the engine. it all can add up to exceeding what the light tells you.

granted you have all your wiring correct, a relay will provide higher current. every light in my truck has a relay. it reduces the stress on the circuit as well. powering a relay requires as little as 5 miliamps instead of 12+ amps for your light. so as long as you are wired correctly, i suggest a relay.

 

[wheelman55]

My simple understanding. Electrical circuits get derated for length and heat. And length actually causes heat. Go figure.

Length - think of length as adding drag to the flow of electrons. With too long of a wire you could actually have little to no electrons flowing. You can defeat this by either using bigger gauge wires or by making your wire run shorter. In a nutshell too long of a wire run leads to derating of ampacity.

Heat. Wires are rated to specific ambient air temps. Go above the heat spec and you need to derate ampacity. Heat is also caused by coiling the wire, and/or by having too many wires in a conductor or too many in a tight bundle.

Your fuse blowing is a safety thing. Without the fuse the heat could build and cause a fire.

It sounds like you did two things to help…you decreased the length of your wire run and removed a coiled length of wire.

FYI. Car Stereo guy knows what he’s doing. Take the rest of our comments with a grain or two of salt. There is a guy named Tony Candella who has written some good books on automotive wiring.

Here‘s a link to Tony’s website: https://ceautoelectricsupply.com/wiring-and-efi-conversion-books/

 

[Oldfart]

Hi Rick, here's a link when I added a relay for my BD's last year. I had to refresh my memory because it was probably 30 years since I put one in. There's a good how to video there for you. It's pretty easy as long as you can do wire crimps, and they are cheap at Advanced or AutoZone.

https://www.fordraptorforum.com/threads/squadron-2-install-blowing-fuses.76558/page-2

 

[The Car Stereo Company]

My simple understanding. Electrical circuits get derated for length and heat. And length actually causes heat. Go figure.

Length - think of length as adding drag to the flow of electrons. With too long of a wire you could actually have little to no electrons flowing. You can defeat this by either using bigger gauge wires or by making your wire run shorter. In a nutshell too long of a wire run leads to derating of ampacity.

Heat. Wires are rated to specific ambient air temps. Go above the heat spec and you need to derate ampacity. Heat is also caused by coiling the wire, and/or by having too many wires in a conductor or too many in a tight bundle.

Your fuse blowing is a safety thing. Without the fuse the heat could build and cause a fire.

It sounds like you did two things to help…you decreased the length of your wire run and removed a coiled length of wire.

FYI. Car Stereo guy knows what he’s doing. Take the rest of our comments with a grain or two of salt. There is a guy named Tony Candella who has written some good books on automotive wiring.

Here‘s a link to Tony’s website: https://ceautoelectricsupply.com/wiring-and-efi-conversion-books/

great info in this post. i didnt think to mention the gauge of wire since it was the wire that came with the light. but @wheelman55 makes good and accurate points

 

[amREADY]

great info in this post. i didnt think to mention the gauge of wire since it was the wire that came with the light. but @wheelman55 makes good and accurate points

Agreed.

And good connectors and proper crimps.

 

[wheelman55]

Agreed.

And good connectors and proper crimps.

And no “SkotchLoks”.

 

[jvike]

@OEMPlus Raptor Did you figure out this issue? I'm having the same experience. My upfitter 1 fuse blows after 10-15 min.

 

[OEMPlus Raptor]

@OEMPlus Raptor Did you figure out this issue? I'm having the same experience. My upfitter 1 fuse blows after 10-15 min.

No I didn't it, it hasn't blown in awhile. It would only blow the fuse while offroading and rough terrain. What I did change was the ground. I'm grounded to the battery now. Not sure if that worked but it hasn't blown the fuse. Worth a shot, let us know if that corrects the problem.

 

[smurfslayer]

that sound a lot like an unsecured connection.