Do I have enough power?

I just had a 4-channel amp installed and the shop strongly suggested that I ad a capacitor to the system.  I had installed, a MTX thunder 564 (75W X 4 RMS) amp with 4 awg power and ground wires.  I already have a RF P3001 sub amp (300W RMS) with 4 awg power and ground wires.  This is all in  a 2006 Toyota Highlander 2 wheel drive 4 cylinder, no tow package.  I don't know what the alt. power output is.  I don't have any lights dimming at any time, but am thinking about adding a sattelite radio to the mix.  Does my alt. put out enough power for the current power draw I'm using?  I don't want to cause any damage to the new vehicle.  What would be the best course of action to take?  I've thought about upgrading "the big 3", don't know how much it would cost though?  Will I really need a bigger alt. or should I be fine with what I have?  I need some thoughts and some suggestions from you guys if possible.  Thanx:)

First off, stock alternators produce enough power to meet the needs of the car, only. So when you intorduce any (larger) electronic device that demands amperage you are automatically putting a degree of strain on the alternator and electrical system.

Now here is th grey area, how much power are you drawing and how often and long does this power draw go for? Currently, if you are not experienceing any light dimming or other effects, you are relatively safe. Keep in mind newer cars have more and more sensitive on board computers, so you should put their safety first.

I suggest you leave the cap out of the picutre and look into the big three. First thing I'd do is upgrade the ground for the battery. Leave the stock one in place and add a second one at an alternate ground point. 

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Big Three indeed...if lights don't dim than don't buy a cap...don't buy a cap period...the shop is just trying to take your money!!!!

Big three should cost only as much as the length and quality of wire you purchase.

The 564 (atleast with my spec sheet) is really more like 85 watts RMS. MTX tends to under-rate their amps. I agree with the big 3 along with some high end battery connectors.

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"People with mullets live 40% longer"   - Ricky Bobby

I vote that we all go to the local peeler bar and contemplate what we should do with this question. I'll get back to you later. In this time, upgrade all main alternator and battery connections, both + and - to 4 gauge at the least. I'll have a drink for you while I enjoy the show.

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Top Secret, I can tell you but then my wife will kill me.

Rob, in case most of you DIDN'T know this already, is a "giver"...

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

*grabs keys and runs for the door*

when you say add extra - for battery you mean just hook it to the battery and run to different ground spot on the frame of car?

Yes...Just add another ground wire from the negative of the battery to the chassis of the car...could use the same spot but just make sure ALL paint is sanded away to bare metal.