I just purchased a complete Alpine system from Crutchfield (pre-amp head unit, 5 channel amp, component speakers, etc...) and am concerned about the power requirements of the amp exceeding the car's alternator abilities. My Camaro is an 89 with the CS120 series alternator rated at 105 amps. Also the age of the car and the 140K miles worth of use on the factory wiring has me concerned about degraded electrical performance. Has anyone developed a complete wiring harness specifically for the alternator/battery/starter circuit? Currently the battery puts out 12.7 V and 700CCA and the alternator tests at 13.9 V with max output of 98 amps at 2K rpm as installed on the car (read at the battery). Am I too concerned?
Russ, you can never get 'too concerned' about the power availability in your car if you have a serious system. I commend you for thinking about this BEFORE something goes ka-put.
Not sure how much amplifier you have but 98amps from the alternator should be fine for anything under 500 watts total (actually a good reading for a 105 rated alt.)
Here's a few suggestions:
-Replace the power lead from the alternator to the (+) battery terminal. Clean the contacts really good and use 4ga cable with SOLID connections on each end. This will ensure that the full 98amps can reach the battery. It's also a great idea to go ahead and pull the alternator so you can wirebrush all it's mounting points and make them shiny clean...this is where the alternator gets it's ground. I recommend covering these 'shiny bare metal' spots with a little axle grease after you have the connections done to prevent corrosion in the future.
-Run 4ga (2ga if you can afford it) from the battery back to the amp rack. Put a fuse (about 80amps rated) on the power lead within 6" of the battery. This fuse is to protect your electrical system in case of a short somewhere..not to protect your amps, you'll still need a fuse for the amp unless there is one built in (probably so if it's an Alpine.)
-Run an ADDITIONAL 4ga (2ga if you can afford it) ground from the battery (-) terminal to the chassis. Use a wire brush and make sure you are on shiny bare metal for the contact to ground. Remember the grease to cover this (or shoot it with paint...something to prevent corrosion from setting in.)
With this done, the amp will get sufficient power regardless of the rest of the car's electrical wiring. If you have huge amps or other electrical bugs (not uncommon on the F-body GM cars) you will just have to track them down one by one.