How to Install A Car Audio Capacitor

To start, I’ll explain what a car audio capacitor really is. A capacitor is a bit similar to your car battery; it stores electrical energy. But unlike a battery it doesn’t produce its own power, it simply stores it. A car audio capacitor will help you get the most from your amplifier. It will store power for release on demand, delivering it to your amplifier just when it’s needed. Your car amplifier requires a lot of power to play loud music, especially when there’s lots of heavy bass. Without a capacitor your amplifier will be robbed of power by parts like your lights, engine, and air conditioner.

Capacitance, or the amount of energy stored, is measured in farads. Most car audio capacitors are one-half, or 1 farad. Capacitors should be pre-charged before installation. This enables them to reach their maximum storage limit without damaging the electrolytic.

It also allows the unit to be installed without arc-welding your connection to the teminal. Use care when charging a capacitor and always do it with a resistor. I typically use a 100-watt, 8-ohm resistor, available at most electronic surplus stores. Most caps come with a 1K resistor, which will work but will take a while and the leads will get extremely hot. If you must use this resistor, hold it in place with pliers. First, ground your capacitor.

Then, before connecting 12-volt power to your cap, take out the fuse under your hood and put the resistor in its place. Basically, just touch the leads where the fuse would normally go. Next, connect power to the capacitor.

It’s also a good idea to have your voltmeter monitoring the cap’s terminals so that you can watch the charging process. Once the cap gets up to 12 volts you can take out the resistor and reinstall your fuse.

Capacitors should be placed within inches of your amp in order to maximize the performance of your system. It’s also important to remember that, while a fuse should be used to protect your system, it must be placed on the charging line feeding the capacitor, NOT after. A fuse inserted between the capacitor and amplifier becomes a resistor, essentially rendering the capacitor useless.