I have a 2003 civic si and am currently thinking about putting a system in it. Which brings to question what is the maximum amount of watts I can safely run in my car without any problem or electrical upgrades.

 

well it depends on what kind of system you want............a system can range from headunit to speakers to subs to flip outs, etc.......

 

since I am keeping the stock deck I am more concerned about how many watts can the amps I am planning on getting be rated at.

 

anyone?

 

First what do you want to run?

Do you even know which subwoofer or subwoofers you want to run?

What about speakers?

Are you going to power your speakers externally?

The stock electrical system isn't made to handle amplifiers... you need to run new wires... of the right size. and improve the efficiency by reducing the resistance between the alternator, battery, chassis ground, and main fuse box... also known as upgrading the big three..

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I think the stock alternator outputs about 70 amps at about 14v dc.
thats about 980 watts

watts = amps * voltage (constant voltage)

 

First, plan out what kind of set up that you want, are you going for mad boom? Then you need to figure up the rms wattage of your system your building. Not the peak. Then divide that by 14.4 volts to figure out how many amps your going to be pulling. Make sure this does not go over your factory alternator. Also the big three as mentioned will help out alot.

 

A pretty safe bet is 500W RMS or less, even 1000W can be run on a stock system, kind of depends on how loud, and long, you want to "crank" the system.

Music is dynamic, so a 500W system will average less then 50% of that under normal listening levels.

1 always recommend an upgraded alt. after 500W of RMS power, but then again if your a bass head and like to sit on your porch with the cars doors and trunk/hatch open and the tunes cranked for extended periods of time, I would recommend upgrading the alt. adding a 2nd batt, and upgrading the stock one and adding a cap.

Assuming the amps you get are 50% efficient you need about 15A of current to make 100W RMS, about 75A to make 500W RMS and about 160A to make 1000W RMS.

With that said, upgrading the alt. in the car can't hurt even with a 100W system. 94