Location of power amp main fuse

[jetta2vr6]

All the wiring kits I have seen have the fuse holder close to the battery. Does it matter if it is close to the battery or the amp?

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[Rockman 10+ year member]

U want the main power wire fuse close to the battery. That way if the power wire shorts behind the fuse, it will blow and protect the wire.

 

[F.A.M. 10+ year member]

The fuse box services 2 functions, to protect the amp/amps and to protect the car.

The fuse is made to pop when you have a short somewhere in the power line to prevent current from travelling down the power cable. Now lets say that you have the fuse box back in the truck and you have a short. The fuse will pop but you will still have live current running all the way back to the fuse box. If the short is somewhere, lets say under the rear seat, it could heat up that area and maybe cause a fire in your car (this is VERY bad).

Now lets say that the fuse was under the hood and the short was under the rear seat. The fuse would still pop, but now, the current does not travel all the way to under the seat, since the fuse is under the hood (preferably near the battery), and you are safe against a fire breaking out.

Now to answer your question, does it matter?

No, not really, you can have it anywere you like. But based on the info you just got, use your best judgement. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[fantomas 10+ year member]

Originally posted by F.A.M. No, not really, you can have it anywere you like. But based on the info you just got, use your best judgement. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

and by 'no', he means 'yes'. if you are going to put a fuse right before the amp, 10 feet away from the battery, dont even bother using a fuse at all. If theres a short somewhere before the fuse, a toasted amp will not matter when your truck is on fire. everything F.A.M. said was true, though. -scott

 

[80_Cutlass_mn 10+ year member]

No matter what it is always best to have the fuse right next to the battery, or as close to it as possible.

 

[n2audio 5,000+ posts]

Originally posted by F.A.M. The fuse box services 2 functions, to protect the amp/amps and to protect the car.

 

I have to disagree with the 1st part. The in line fuse can't possibly protect the amps. It's simply to keep your power wire from becoming a heating element in the case that it's shorted to the chassis.

 

[CarAudioAddict 10+ year member]

N2audio is correct.

The only reason for having a fuse next to the battery s to protect the wire and the car. Most decent amplifiers have built in fuses to protect the amplifier itself.

Some people (read: stupid people) will forgo the main fuse all together. Needless to say these are the people who end up with a pile of melted metal and fabric where they last parked their car.

The Fuse in your main power wire should be no more than 10 inches away from your battery.

In a system like mine, where you have the battery in the trunk/hatch of the vehicle, I have a fuse off the battery and another off the alternator. This way if a short occurs the entire wire will be disconnected from everything and there is little if any chance of fire.

 

[F.A.M. 10+ year member]

Originally posted by n2audio I have to disagree with the 1st part. The in line fuse can't possibly protect the amps. It's simply to keep your power wire from becoming a heating element in the case that it's shorted to the chassis.

So what you are saying is that if someone who does not use an in-line fuse, and that their amp does not have a built in fuse (yes there are amps that do not have built in fuse) and lets say that they have a bad ground, that their amp will be fine?

I think not.

 

[fantomas 10+ year member]

how does the mtx 81000d become protected? it has no built in fuse...but requires a 150 amp inline. if the fuse only protects the wire, whats the point of building amplifiers with fuses built in? -scott

 

[F.A.M. 10+ year member]

Originally posted by fantomas how does the mtx 81000d become protected? it has no built in fuse...but requires a 150 amp inline. if the fuse only protects the wire, whats the point of building amplifiers with fuses built in? -scott

My point exactly, the in-line fuse protects BOTH the wire and the AMP.

 

[n2audio 5,000+ posts]

Originally posted by fantomas how does the mtx 81000d become protected? it has no built in fuse...but requires a 150 amp inline. if the fuse only protects the wire, whats the point of building amplifiers with fuses built in? -scott

A lot of higher priced amps have circuits built in for current protection (like mine). Power down, they reset. More times than not, if you have an amp with on board fuses, and you do something that pops one, your amp just went up in smoke, but possibly saved your car from doing the same.

Originally posted by F.A.M. So what you are saying is that if someone who does not use an in-line fuse, and that their amp does not have a built in fuse (yes there are amps that do not have built in fuse) and lets say that they have a bad ground, that their amp will be fine?

I think not.

No, not what I'm saying.

Not an applicable analogy anyway. If you have a bad ground the current path is restricted -- Less current, less chance of power problems, just less output from the amp.

However, if that wire gets grounded before the amp(cut - comes in contact with chassis) then yes, the amp will be fine because all the current that will flow through the wire -- in this case, all the current the battery can put out -- will be trying to flow through the wire directly into the car's chassis. The amp will never know it happened, effectively there is no circuit beyond the point of grounding. This is the dreaded situation that will turn the pwr wire into a heating element and likely cause a major car fire.

Originally posted by F.A.M. My point exactly, the in-line fuse protects BOTH the wire and the AMP.

If you say so.

 

[MikeofTulsa Moderator]

an inline fuse is recomended.....most amps come w/ fuses to protect them in case a person does not add an inline fuse...some do not....an inline fuse is always recomend since it does protect the wire and possibly the amp if it gets a power surge and does not have an inline fuse

 

[F.A.M. 10+ year member]

Originally posted by n2audio No, not what I'm saying.

Not an applicable analogy anyway. If you have a bad ground the current path is restricted -- Less current, less chance of power problems, just less output from the amp.

Not true, if your amp has a bad ground, then the current flow will be impeded. This will result in the amp working harder to draw current, which will cause the amp to heat up and possibly overhead. I have seen this happen to plenty of amps in ghetto rig cars over the years.

You guys can believe which ever one of us you want, but we both agree that fuse does protect the wire from being a possible fire hazard.

Just run an in-line fuse, and keep it close to the battery.

Nuff said, onto new things.

 

[n2audio 5,000+ posts]

Originally posted by F.A.M. Not true, if your amp has a bad ground, then the current flow will be impeded. This will result in the amp working harder to draw current, which will cause the amp to heat up and possibly overhead. I have seen this happen to plenty of amps in ghetto rig cars over the years.

Sorry, one more comment. What's happening there isn't thermal shutdown, in that case the amp cannot draw enough current to supply the output being demanded. That's not thermal shutdown, it's current fault protection. Happens to me all the time when I'm working on something in my car with the stereo playing. After an hour or so of running only off the battery the amps power down b/c the voltage being supplied is too low.

Originally posted by F.A.M. Just run an in-line fuse, and keep it close to the battery.

Nuff said, onto new things. [/b]

Amen

 

[fantomas 10+ year member]

Originally posted by n2audio Happens to me all the time when I'm working on something in my car with the stereo playing. After an hour or so of running only off the battery the amps power down b/c the voltage being supplied is too low.

You mean to tell me that you dont disconnect the battery before working on your car...? ...and then you let the battery die....? -scott