Battery/alternator power?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=17904
Printed Date: July 27, 2025 at 2:31 PM
Topic: Battery/alternator power?
Posted By: jpilson21
Subject: Battery/alternator power?
Date Posted: August 21, 2003 at 3:02 PM
I'm considering a custom stereo system for a 1997 Dodge Ram truck. I just installed a brand new Interstate battery, and had the alternator tested. I'm trying to make sure that the battery and alternator are giving enough power and voltage to safely run the stereo components plus the truck electrical system. Can anyone help?
The battery has numbers that I don't understand.
CCA=875 CA=1095 RC=165
The alternator was tested at 14 volts, and was told a regulator can be added to increase this amount if needed.
The stereo system will be powered by (2) amplifiers.
The first is a 2-channel amp with 600 watts total.
The second is a 4-channel amp with 1400 watts total.
It was recommended that I add a 1-farad capacitor to help with power surges.
All of this is Greek to me - can anyone point me in the right direction?
Replies:
Posted By: bberman1
Date Posted: August 21, 2003 at 4:20 PM
Are the total watts above RMS or MAX ? Also do you know the out put of your alternator?
Posted By: jpilson21
Date Posted: August 21, 2003 at 4:38 PM
My mechanic tested the output voltage of the alternator at 14 volts. However I don't know how this converts to amps or watts.
The amplifier wattage is the total watts for each amp.
RMS wattage for the 2-channel amp is 150 x 2.
RMS wattage for the 4-channel amp is 175 x 4.
Posted By: bberman1
Date Posted: August 21, 2003 at 5:09 PM
That is 1000 watts total rms, 1000 watts will use approximately 78 amps. You can call the dealer or an auto parts store and they will be able to tell you how many amps your stock alternator puts out. Typically if your audio system draws more then 1/3 of the out put of the alternator then you should upgrade to alternator that can handle the current.
Posted By: jpilson21
Date Posted: August 21, 2003 at 5:24 PM
Can anyone tell me what those numbers mean on the Interstate battery? (See my original message.) And should I have a capacitor? (I understand what it does - but can't find any info on how you determine whether or not an audio system needs one....)
Posted By: frozenfoodman
Date Posted: August 21, 2003 at 7:45 PM
CCA-Cold Cranking Amps
CA-Cranking Amps
RC-?
Posted By: speedwayaudio1
Date Posted: August 22, 2003 at 7:26 AM
if you upgrade your alt to 150amps or more you will not need a cap. caps are nice i like them but you really don't need it.
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Big Dave
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