What Size Fuse To Use?

Just to give you a comparison, my old Tantrum 1200.1 amp required an inline fuse of 80 amps and it pushed out about 1520 watts rms. So I doubt you'd need an inline fuse much more than that for your amp that pushes 1800 watts rms. I honestly think a 100 amp fuse would suffice given what other similar powered amps require.

 

Fusing your 4 awg wire protects your wire, not the amp. This is the way I understand it. Also, seeing your amp has fuses installed in it, you should be fine.

 

Too large of a fuse, and you risk not protecting what's supposed to be protected. In the case of an underhood (or in this case, main power wire) fuse, that's the wiring and the car. In the case of amp fusing, it's the amp componentry.

Too small of a fuse, and you risk popping it during normal operation, when there is no danger. That's no fun, just annoying.

 

I think a 120 amp fuse on the 4 awg wire going to your sub amp would be a good size to use. It's clearly not too large and it shouldn't be too small for that amp. If that is too small (which I highly doubt it would be), then just bump up to the next available size.

 

In YOUR case - 4 gauge probably can - but that's only because your total wire run here is only going to be something like 4 feet!

However, the wiring between your ALTERNATOR and the battery in the back has to be considered, since this will be the main supplier of current!
So, this likely will need to be 1/0, even with the battery relocated to the back - the battery isn't your current source.

 

do a search on the "magic 3"
-Cody

 

James, geo is talking about upgrading your "magic 3", not replacing any wiring. It is pretty easy to do and well worth the effort. There is a good tutorial over at Sounddomain's forums about this: http://forum.sounddomain.com/forum/ultimat...ic;f=5;t=007801

Also, just because I am ignorant, is your battery in the back of your car by the manufacturer's design or did you add a second battery to the back of yout car for your uadio install. I never saw you mention one way or the other.

 

most small cars have batteries under the back seat now...my mom's buick lesabre is like that
-Cody

 

Wow, didn't know that. Is that to prevent any battery explosions from heat?

 

Didn't know that - I own a Hon-duh, which has a battery under the hood.

 

its to free up space under the hood...not battery explosions
-Cody

 

In your case, you have to worry about "the circuit".. that's all.

There are potentially two sources of power in your system, correct?
The alternator, when the car is running...
And the battery, when the car is not - or when the alternator is momentarily overtaxed.

Well, if you are running thick power wire from your battery to your amps - all you are currently doing is ensuring that you have adequate enough power wire from the battery to the stereo equipment - which would be fine, if the battery were the only voltage source.

After all.. you can trace that circuit, mentally:
Current flowing from the + terminal, through your power wire, into your amp (which uses it to make music), out the ground wire, to the ground location, through the car's chassis, back to the battery's - terminal.
(in reality, current flows the other direction, but that is a minor, unimportant technicality in the scope of this point).

Now, instead - since the alternator is your primary source of current - and more importantly, one source that you don't want to choke off, making it inefficient for the alternator to do it's job - let's trace that circuit:
Current flows out your alternator's + post, through some [at this point] mystery wire, aaaaallll the way back to your rear mounted battery... ...where the current then flows into your power wire, into your amp (which uses it to make music). Then, the current flows our your amp, through the ground wire, through the chassis, through the ground wire to the engine block, through the engine block itself, finally returning to the alternator via its chassis ground.
Phew! That one was much longer.

My question is - do you believe this "mystery wire" is large enough to support the current draw that you are going to be potentially pulling through it?

 

Glad we were able to help. I gotta say that goe's last post was very good about laying out the whole circuit idea in layman's terms.

James, I would suggest you really think about upgrading the alt to + battery wire since you are going to be running a pretty beefy amp. I also suggest this since you are getting all your wire for cheap or free. You could always use the wire again in your next car.

 

Damn double posts.