Is there any way to tell if I'm stressing the alternator with my sound system/lights? Voltmeter perhaps?

 

How much power are you running? Stock alternators on civics produce 440watts peak, if you are using more than that on a constant basis, you will undoubtedly do damage to your alternator over time. Your oem battery will die soon also.

 

your light will be alot dimmer than usually.

 

Well, I have a 98 Prelude and I have a 560W sound system, which isn't overly much but I also have *a lot* of lighting effects. Now most of those lights don't use up much power, but I'm thinking since they're combined all together it might be stressing. But I don't run with all those lights on all the time.

 

Watts isn't what matters it's amps.
You need to read your manuals and see how much amperage your stereo and lighting is pulling.


[Modified by Spade, 10:18 AM 1/25/2002]

 

You'll need to use an ammeter, not a voltmeter. Like Spade (?) said, it's amps, not watts, you need to be concerned with. There are three things you need to determine...

1. How much current can your alternator produce? This is what you've got to work with, and it should be listed in your car's manual.

2. How much current does the car draw with all accessories turned on EXCEPT the sound system, lights, etc.? Use an ammeter with an inductive probe to measure it. Turn everything on, including A/C, rear window defogger...

The difference between these two is your alternator's "headroom."

3. How much current does your stereo/lights draw? For the lights, you can convert watts to amps with Ohm's Law, but don't try that with the stereo -- the results will be meaningless. (Lights are DC watts, stereo is AC watts. Different animals.)

If this fits comfortably within the alternator's headroom, you're good to go. If not, you're gonna put a strain on your battery/alternator.