I just installed new amps/subs and my cars voltage seems pretty damn low. When I'm moving it's around 13 and when I'm at a light it drops to around 12. Anyone out there with a totally stock stereo? What's your voltage normally read?
If this is abnormal(which I'm thinking it is), what do i do to fix it? I'm running about 2000 watts max power.

 

Nope totally normal and following the voltage laws of Kirkoff, Ohm, and Watt. These are laws that can not be violated with the physics that we know of today.

You're asking your battery and alternator to supply over 200 amps of power which is completely impossible.

Your stereo system has 200 amps worth of power draw give or take and then things like the head end (10 amps), A/C, lights, and engine are going to draw another 20-30 amps. You'll need a second battery of massive size, a second battery charger system, and a larger alternator. Police and taxis will often have alternators rated at 90-120 amps and one of these might be added to your car.

 

All that? Damn, my system isn't THAT powerful. It's a phoneix gold Octane-R 15.0:1 and a phoenix gold Phoenix Gold Octane-R 8.0:4.
I mean...DAMN!! Most people on here don't have extra batteries, alternators, or any of that stuff.

 

OK

You said 2000 watts worth of energy. I was assuming Zapco Competition amplifiers. I was thinking closer to $2000 an amplifier times two not $200 each.

I assume you're measuring the voltage from the triple gauge cluster? That thing is pretty accurate compared to what I'm reading with my digitals. It's normal for the voltage to drop a bit at idle. While driving it ought to rise up to 12.7-13.6 volts.

Do your lights dim with the bass beat?

If you shut your stereo off at the stop light does the voltage rise back up?

 

I have a optima yellow top batery, and my voltage never goes below 14.4 while driving. at idle the most it will go down to is about 13.5. thats at high volume...Its not good for your stock batery to discharge and recharge that rapidly... you will definetly need a new batery soon. I would get a deep cycle batery, somthing with at least 700 cold cranking amps...also its bad for the amps if your voltage goes down to low. plus low voltage=low sound..

 

Read once (from Nazar?) that the GROUNDING from the battery to car is insufficient. You might try adding another wire or larger one.

 

Watching my battery voltage tonight while cruising around it never dropped below 13.7 volts even at idle with the stereo thumping, AC blasting, and the highbeams on.

 

There shold be a fuse within a few inches of the battery for your amps. Take the fuse out, drive around a bit and watch your battery voltage. It is typical for voltage to drop when idling, as your RPMs are low and current generated from the altornated is proportional to engine speed. This leads to less current at idle, meaning a voltage drop. If it drops close to 12vdc I personally would start to worry. The stock battery and the amps will be fine - the battery won't be damaged as long as you don't discharge it COMPLETELY. Rapidly changes in load won't affect the life of the battery. High quality amps will have power supplies to help absorb voltage drops and will have a protection mode to protect them in case of low voltage. What I would worry about is the stock ECU and BCM. Both units are very critical to the car, and rapidly changing voltages from a taxed charging system can lead to premature failure. For best operation you need a stable electrical system, with plenty of power availible. It's no secret that the VQ35s alternator is fairly small, and NOT designed to run aftermarket audio equipment.

A yellow top battery will help in the long run, as it can provide more instantanious current and it charges faster. These two features will provide a better environment for your electronics! Oh, and a cap on the sub amp will also help stablize your battery voltage.

 

My system is going to consist of 2 xtant 302a's and 1 xtant 301a, totaling about 900 watts off the stock battery and alternator and a 1 farad stiffening cap.

I'm thinking I should be ok with this setup, but just wanted to confirm this or see if I needed a battery?

 

Where can I get a yellow top and how much are they? I just added a capacitor today and it's going crazy. LOL
The voltage is dropping to almost 10 volts when the subs are hitting hard.

 

http://www.1st-optima-batteries.com/

Any loads beyond 90 amps is going to drain your battery with the alternator running. That's a WAG as to what our alternator is good for at speed. You amps are going to draw maximum power unless you're at maximum amplitude levels.

 

Which model battery fits in the Z?

 

what can you recommend as a good alternator?