is my battery taking a hit?

You have asked this same exact thing 4 times now and I have told you IT'S FINE 4 times now...

" and its reading most of the time 13.2 13.3. and sometimes it reads 12.9 12.8 and goes back up"

Now you are saying 12.6 and 12.4....

Your voltage is going to drop... It's normal.. 

You said you didn't want to spend any money on upgrading your alternator or battery but you keep making these post hoping someone will tell you to upgrade something.

So go buy some 1/0 wire and upgrade the big 3 then.

Your alternator is only 100a which is very small and it can't keep up with the current draw from your amps. When that happens voltage drops and it means your electrical system is not strong enough and it's time to upgrade. 

Charbel Bernaba said:

very small for 1000 watt not even system?

Click to expand...

Yes, it takes 100a of current to sustain every 1000w of amplifier power. The vehicle needs to power to run all of the electrical components, on that car prob at least 60-80a. Add it all up and you are trying to draw 160-180a from a system that can only support 100a. You need to upgrade your electrical system. 

Charbel Bernaba said:

180 amp is good?

Click to expand...

Are you asking if a 180a alternator is big enough for what you have?

Go with the highest amperage that you can afford. 

Hey mate,

You did not specify your amps that you are running so please provide the details.

With a stock electrical system, most cars will take up to 1000watts rms, with a stock alternator, (this has been verified by Richard Clarke and David Navone, (Car audio and Electronics magazine), showing my age here! :nerd:

If you are running class D amplifiers, that will be ,much easier on the cars electrical system, since the above statement was made when CLASS D amplifiers were not too common or were not released in the car audio field.

Just to further prove a point, I am running 880rms to my subwoofers using a CLASS D monobloc and a Class A/B amp running 200watts rms to the components.  So I am doing over 1000 watts but that is fine since music is transient, not constant like a light bulb.   Think of it in another way, you don't drive your car with your system in full tilt, whilst having the ac on at full ball, and have the wipers going and your interior lights one together with your driving lights,  :suave:   I am sure you are getting an impression now,    The good thing is that music current demand are higher when the subwoofer kicks in but with speakers, they would be screaming enough with even 100rms x 2 so you will need to turn it down to protect your hearing :graduate:

Anyway, you look at it, your system is fine but just provide us which amp your are running so we know you will not be starting a fire if you are using el-cheap amps that have exaggerated power ratings AND that your system has correct power/ground wiring / circuit breakers / fuse holders to protect your ride in case of over-current. 

If anything that is risky it would be driving the amps to abuse, then your fuse should pop and this will prevent any damage to your cars electrical system as well as your amp blowing up or worst scenario, catching fire.  As we don't know what amp you are running  One advice is to stay clear of those flea market / second hand amps that looks battered and missing screws/ different fuse is definitely a give away signs that the previous owner did not bother to secure the amp in their ride. :uhoh:

Please let us know the amplifier in question so we can further provide some advice and guidance in your case mate! :fro:

Charbel Bernaba said:

does a big alternator like 200 amp+ hurt my car i dont wanna damage my car. my dealership toyota said a big alt like that will blow everu fuse in the car.

Click to expand...

Wut/....lol