Problem hooking up amp &woofer in car

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Joy
Joy's picture
Problem hooking up amp &woofer in car

Our teenage boys are all hooking up amps and big woofers for their cars. They have come across to problems. One car, the lights in the car will dim every time the woofer hits a hard note..
Second car: every time the woofer is turned on all the electrical equippment in the car turns off completely.
The amps are hooked directly to the car batteries using 4 guage wire. The 1st amp is 800watts and the second car has 760 watts.Both are hooked up the the radio by Remote wires and rca cables.
The first car has a new battery and the second does not. I do not have info on the radio/cd players in the cars. What do you think? Thanks

Matt Whitlock (not verified)
Guest's picture
This is a very good question

This is a very good question that you pose.

Car electrical systems are limited in the total amount of power delivery that they can output at a given moment. Large power amplifiers like the ones you've mentioned can chew up more power than what the car is capable of producing when a big note comes, which is why the headlights on the first car dims. The second car may have more problems, since merely turning on the amplifier shouldn't cause all of the electrical equipment in the car to turn off, but i suppose it is possible.

Given the monstrous amplifiers they're installing, they'll want to add a capacitor to the 12-volt electrical system to decrease the load the amplifier puts on the car's electical system. These large capcitors store a good deal of power when the amp is using less power during soft passages, so that when the big one comes, the amp consumes the current from the capcitor before feeding off the car's electrical system. This works because bass passages in music are not constant, but rhythmic. The capicitor charges in the period between booms. Here's a link to see some examples from Amazon.

The capicitor will most definately take care of the dimming on the first car, but the second will need more investigation. It could use a new car battery, but there could be a short somewhere between the battery and the amp, or it may not be properly grounded. If you purchase a capacitor for the first car, try installing it in the second car first. See if that helps solve the problem. You'll undoubtedly need a capacitor for the second car anyway, but beware that it may not entirely solve the problem.

Whatever capacitor is chosen needs to be capable of supporting a system to about a 1000 watts, which should allow a little overhead to be safe. Post back here on their progress to help others figure out car audio issues like this one.

Joy
Joy's picture
Ok, I'll try that, but

Ok, I'll try that, but another thing that is happening is I have 1 12" Subwoofer right now running in bridge mode on the amp and the amp is over heating if i turn it up somewhat, and I was wondering if I just got another subwoofer and took it out of bridge mode would it make the amp not over heat? because it doesn't overheat when it's not in bridge mode. my friend has a 1000 watt audiobahn running 2 12" subwoofers, and it doesn't even get hot at all. So I was wondering if I should just get another sub and that would make it cool down, or is there anyway I could hook up some sort of fan or something to cool it down so it doesn't turn off to cool down?

Also, I have 4 gage wire going from the battery to splitter, then I have about a foot of 8 gage wire going to the amp, does that make it lose power too so the amp isn't getting as much power on the draws as it should be?

thanks for the info on the capacitor I'll look into one.
Kevin

Tie Guy
Tie Guy's picture
Is your amp an 800 x2 or an

Is your amp an 800 x2 or an 800 bridged? I ask because adding a second sub is still placing a similar amount of strain as it would with 1 sub bridged.

I would replace the section of 8 guage wire, it'll do nothing but give you headaches at this level of power. I'm not going to say that it is the culprit for the amp shutting down (maybe...), but it's like driving a race car with 14" tires from a Ford Focus.

Matt Whitlock (not verified)
Guest's picture
I agree with Tie Guy; the 8

I agree with Tie Guy; the 8 guage wire should go. I was going to ask the same question about the amp, 800 by 2 channels (1600 - 2000 bridged) or 800 by 1 channel in bridge mode.

You also mentioned a "splitter". Are you referring to a distribution block?

Joy
Joy's picture
i don't know what it is

i don't know what it is called, but it's the thing where the wire goes into from the battery, then goes from there into the amp. Because when my brother hooked it up, he has 4 gage wire going to the thing, then 8 gage going to the amp.
As far as the amp goes it' 400 per channel 800 watt bridge, And I have a 1000 watt MAX 400 RMS 12" Pioneer Subwoofer, With a 800 Watt Pioneer Amp.

Matt Whitlock (not verified)
Guest's picture
That amp shouldn't be enough

That amp shouldn't be enough to bring down everything in the car. You should check for a short, or try replacing the battery on top of adding the capacitor. Worse yet, it could be a problem with the alternator, but I'm not an expert in automotive systems. Can any car buffs chime in on this?

Paul Thomas
Paul Thomas's picture
What kind of car is it?

What kind of car is it? Include year too. What size fuse was installed after battery. Somewhere you have something that is not connected right.

Also you mentioned one of the amps getting warm, They normally get pretty warm, if its a good amp it should have a thermal shut off switch. Check the ohms of the speaker and the lowest implements of the amp. How long is the 8 guage wire? If its less then 4 feet I think your ok.

Joy
Joy's picture
Will this do the job?( your

Will this do the job?( your above link didnt work...)
POWER ACOUSTIK 1.0 FARAD Digital Power Capacitor (POWER ACOUSTIK PC10F)
by POWER ACOUSTIK
The 1st car is an ford escort 99, 2nd is a older jeep cherokee.
Thanks again!


Matt Whitlock (not verified)
Guest's picture
Amazon seems to be having

Amazon seems to be having some problems at the moment, which is why the link isn't working. As soon as Amazon gets them resolved, I'll make sure that the link works.

It looks like the PC10F will be fine for the vehicle that is having problems with the headlights dimming, but I can't make a recommendation on the car with more serious issues until they are resolved.

Have you had any luck in the diagnostic yet? Paul is heading in a direction that also merits investigation.

Kevin Crane
Kevin Crane's picture
Umm, the 4 gage wire runs

Umm, the 4 gage wire runs from the battery to the thing (don't know what it is called, little goldist metal thing with a plastic cover) then there's a 1 1/2 foot 8 gage wire going into the amp...What do you mean if the 4 gage wire is less that 4 feet? Let me know as much as possible, I'm trying to learn about this stuff and you guys seem to know ALOT!
Thanks,
Kevin

Paul Thomas
Paul Thomas's picture
I think you miss read my post

I think you miss read my post. With the amp size you said I would not want more then 4 feet of 8 gauge wire. You are pulling so much current, that with the smaller wire the resistence goes up. This will cause the voltage across the +12 and -Bat to drop, and inturn cause the amount of watts (Power) the amp can draw. Watts = Volts * Amps. But with only 1 1/2 feet you don't have anything to worry about.

The "Thing" you talk about seems to be a distrobution block. Do you have a voltmeter?

Kevin Crane
Kevin Crane's picture
Oh, i got what you are saying

Oh, i got what you are saying, but what I was asking was if I excahnge the 8 gage wire with 4 gage wire, would that do anything?

And No I don't have a voltmeter, I think only like Audiobahn or really expensive amps have those..

Paul Thomas
Paul Thomas's picture
No changing the wire wouldn't

No changing the wire wouldn't do anything. By voltmeter I ment a tool. If you want to fix this yourself you will need at least a multimeter, you can pick them up at Radio Shack for $20. Just get the cheapest Digital one they have.

Kayo
Kayo's picture
It sounds like you are on the

It sounds like you are on the right track to solving the issues with the jeep. If you have a manual for the jeep I would look up how to test the electrical system with your new voltmeter (If you are going to get into car audio, this tool will be your best friend). As for the pioneer getting hot: How is the sub wired? What I am asking is is the sub at a 2 ohm load or 4? I had a friend with a pioneer 780 watt amp that got very hot when run bridged with a 2 ohm load. He solved the problem with a large annoying fan. It was not clean, but it worked. The heat just seems to go along with pioneer amps. Well good luck, and enjoy your system. Oh and the foot or so of 8 gauge shouldnt hurt anything. Do you have another amp hooked up in that car, or why do you have the distribution block? If you only have one amp, just run the 4 gauge wire to the amp, it will only make the system better. Oh and what size is your ground wire? It should idealy be 4 gauge, and you might be able to skate by with 8. I personaly recomend replacing all of the 8 guage wire, I have seen a few car fires that resulted from too much current through an 8 guage wire. I always use at least 4 to be on the safe side.

Joy
Joy's picture
Sorry for not getting back to

Sorry for not getting back to you sooner with the results. I've been busy with baseball all summer, I hooked up the capacitor and the lights and everything else didn't dim anymore, Thanks Alot.
Sorry for not getting back sooner,
Kevin

 

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