12V source for my amp!?!?

[hughes1059]

new stereo i got was wired by my father in law to be and he bypassed the amp wire... i need a 12V source that wont kill my battery when the truck is off... tried the lighter but popped the fuse without thinkin!!! any ideas!!!

[JoulesWinfield]

Are you saying that you want a power wire for the main power on the amp that is off when the key is off?

Thats not the right way to do it.
On any amp worth wiring there is a remote wire that you should connect to switched power, either off the stereo (usually blue) or find your own.

Your main power for the amp better come directly off the battery with its own fuse within 24 inches of the battery.

You cant wire anything additional through an existing circuit without first doing your home work (check wire sizes, potential damage to other devices etc.).

The only other way to do it would be to have a relay capable of handeling the load of the amp then wiring the coil from a switched leg and power from the battery.

[TheBrettster]

Fuse Relay center is what i used.

[yeags]

Joules is right . I know it's a PITA, but you really should run a direct line to your battery for your amp, and it should be fused within 12" of your battery. If you don't do this, depending on the power requirements of the amp, you run a couple of risks... You really shouldn't use an existing circuit since the amp could draw too much and blow a fuse that shuts down something you really need when driving. If it doesn't blow a fuse, but the amp doesn't get enough power, it may give a distorted output or a limited output. This will either help you blow your speakers or not give you the output you deserve from your amp. Bottom line... anything less than straight to the battery will be no good.

Now, as far as the remote on power line goes- that can be a much smaller gauge wire, and only tells the amp when to turn on (basically when the radio gets turned on). You can either find a remote on line on your radio, or wire in a seperate power line with a manual switch for the remote on.

Be sure you have a good ground (clean, bare metal contact, and close to the amp) since this is the most common place that engine noise can sneak in. Also remember that your ground cable needs to be the same gauge as your power wire (i.e. 8ga. in - 8ga. out)

I usually run my signal cables and speaker cables down one side of the car, and my power cables down the other (engine noise can sneak in there too).

Have fun, and good luck.

[TheBrettster]

Originally Posted by yeags

I usually run my signal cables and speaker cables down one side of the car, and my power cables down the other (engine noise can sneak in there too).

You always caulk the holes you drill threw the firewall. I've been using the relay center and never had a problem and I'm pushing 6.5k watts. But I is better to run it to the battery I didn't want to have the wires go across the bay.

[JoulesWinfield]

I agree with yeags reguarding runing power and signal wires on opposite sides of the car, I do that as well.

Are you really running 6,500 watts? Thats approxamtely 542 amps @ 12volts. Where the hell are you getting that much power from a normal vehicle? You would need to run 1000mcm cable for power and ground.

Seriously though, when you pull a wire thorough your firewall you can usually run it through an existing grommet. If not when you drill a hole in the firewall the best thing to do is use a grommet. I have taped the wire where it goes through and then use some flexible gasket maker or silicone calk.

[TheBrettster]

Yea i'm running 2 Perfomance Tekniques 3000 Watts and a 500 watts PT running the mids. I have a 180 amp alternator and 2 optima batteries. Ill post pictures if you want.


Its not 6500 Watts constant.

[JoulesWinfield]

Originally Posted by TheBrettster

Yea i'm running 2 Perfomance Tekniques 3000 Watts and a 500 watts PT running the mids. I have a 180 amp alternator and 2 optima batteries. Ill post pictures if you want.


Its not 6500 Watts constant.

If those amps really push that much power even just peak you need to run wire large enough to handle it. Thats 250mcm per amp btw.

You could go smaller but you run the risk of melting the wire and/or choking the amp.

Also you really should be running a 3 farad cap bank per amp as well. And that 180 amp alternator may seem like a lot but with that kind of draw you are going to toast it pretty quick. I wasnt joking about the 542 amps number. You can make up some of that with multiple batteries but not all of it.

At some point, relativly quickly, you will drain the batteries and the alternator will not be able to keep up with the demand.

You really need to do some engineering before dropping a 6.5kw system into a vehicle.

Back to the op; check out the 12volt.com to find a wire that you can use to turn on your amps.

[yeags]

Hey Hughes - sorry to get away from your topic... but...

Brett-

You never want to drill a hole and just caulk it. You NEED to use a gromet as Joules says (I also use caulk with the grommet). If the caulk wears, the wire rubs. If it rubs, the wire insulation can break through. If it does that- you'll be lucky to just blow a fuse. If you haven't fused the line adequately on both ends (battery end and amp end), then you have a simple way to start your car on fire.

Question for you... If you're running a second battery, why wouldn't you just get the power for your whole system directly from there? Either way, with that much power- I think you really would be better served with a good sized capacitor. That will stay full of juice and will feed the amp directly (and more instantaneously) than a feed from a battery or whatever.

You are right in the sense that the Relay center does get a fair amount of power, but it doesn't get an unlimited amount of power - the other things connected in the relay center will also draw off that power line (probably not at the same time, but they will draw). When they do- either the amp or the other electrical device will not get all they need if the amp is running hard. If you go easy on the amps, it probably won't matter.

As for running it across the engine compartment- either run the wires up the other side, or go through the firewall and then hug the engine side of the firewall and wrap it around to the battery. Just use some flex loom and either screw type wire brackets (preferred), or zip tie it to existing wire.

[TheBrettster]

Well i didn't install it. All i know is theirs a 160 amp circuit breaker right before it connect to the relay and the battery connect to the other battery. Their is also a 4 slot fuse block under my back seat with 4 80 amp fuses in it. There is 0 gauge going to the block then from the block is 4 gauge to each amp. PLus the amp are toned way down I believe at 15 or 10 percent, to loud if i go anymore .

BTW There is 2 3.0 Fared Power Acoustik caps . One for each amp.

[yeags]

That sounds better!! I think I'd just run that main power to the 2nd battery if it was mine.

I like the caps, and I like that they are turned down- use the clean part of the amp to sound the best and be the safest for your speakers.

What kind of head unit are you using?

[TheBrettster]

Pioneer DEH p680MP

[JoulesWinfield]

Not to insult TheBrettster, but I dont think you can get 3000watts for $350.
I have yet to see discount equipment produce upscale performance.
Its been my experience that if you are paying less than a dollar a watt (friendly hookups and used equipment excluded), youre getting substandard equipment.

[TheBrettster]

Who said i paid but "I dont think you can get 3000watts for $350." and yes it was a discount cause i do trade work for the stereo shop. What came out of my pocket was around 1600.

[JoulesWinfield]

Originally Posted by TheBrettster

Who said i paid but "I dont think you can get 3000watts for $350." and yes it was a discount cause i do trade work for the stereo shop. What came out of my pocket was around 1600.

I actually have no idea what these amps are, I just did a quick search and found a couple of places selling them for around $350.