Car Stereos: Concerned with my Subwoofer, watts rms, pontiac sunfire


Question
Hey Scott I have a few questions for you about subwoofers and setup.

Basically i bought a sub, box, amp, and wires from one of my great friends a few days ago. We hooked it up at his house the other night and everything is working fine, i can change the settings and power of the sub with my sterio and all that jazz.

What my issue is, is that i know NOTHING about subwoofers or amplifiers for that matter! The sub i bought is a 10 inch Alpine, and the Amp is a 5-channel Kenwood and he said its power is 250RMS and 750Max. (no idea what that means)

To add to this, i have VERY dim headlights (they were horrible before i hooked up the sound system) and i am going to get halogen lights which will be very bright.

Pretty much what im asking is, Is there any chance of my car battery failing because of to much power being run to my headlights and my amp? Or will one 10inch subwoofer not effect it. A few of my friends suggested that i get a capacitor but i dont know what that really does. Do you know any websites that will explain all this in SIMPLE terms?
PS: I have a 2000 Pontiac Sunfire, if that means anything.
PSS: Sorry if this question is ALL OVER the place.

Answer
Bill, No problem.  I wish there was a website for easy explanation, but I have not found one yet.  I will answer your question in three parts.

First, You always want to compare parts using the "rms" watts, not the max watts.  RMS watts are based on a set test.  Max is based what that company thinks their speaker or component can handle before it gets ruined.  Each speaker or sub is a channel.  With a 5 channel amp, all the channels are not being used, unless it is powering all of your car speakers as well.  Which I am assuming it is not.

Second, capacitors are nice but not needed on systems with less than 300 watts.  There is additional draw on your battery for the added amp and halogens, but that does not affect the battery too much.  The affected component is the alternator.  You will probably need to replace the alternator prematurely to when expected.  I would suggest, as a first component upgrade, getting a high output alternator.

Third, there are no dumb questions about mobile electronics.  If you would like to know anything else about the stereo system, even the headlight issues; I can steer you in the correct direction.  One of the best ways to improve(brighten) headlights, is to use relays.  All cars turn lights on through switch on the dash.  There is a lot of power lost from the battery to the switch and from the switch to the headlights.  Also, the switch loses alot of power in it's connection.  A relay shortens the wires considerably and has a better connection for minimal resistance.  Try danielsternlighting.com .. He is very knowledgable and will get you driving more safely soon.

Hope this helps,
Scott