Car lights dim when the bass hits? Unfortunately, the solution
to this problem is not cheap or simple.
The electrical system in most cars is designed to supply power to
all the factory-installed components and accessories. If you add power-hungry
amplifiers, the car's electrical system can not keep up with the current demands.
The car's components and your audio system are in a constant fight for the low power
The first thing to do is to add a stiffening capacitor. A
capacitor acts as a secondary battery that reacts very quickly to sudden current demands
(i.e. music transients). A rule of thumb is to have 1 farad of capacitance for every
1000 watts of power. The sound system will sound a bit smoother and hopefully the
light dimming problem will be either fixed or reduced. Your lights don't necessarily
have to be dimming for you to have to add a capacitor. Stiffening capacitors always
help a sound system.
Capacitors should be installed as close to the amplifiers as
possible, with the positive lead going right into the positive lead of the amp and the
ground to a metal part of the car (not to the ground terminal of the amp).
When a capacitor is first installed, it has no voltage in it, so if
it is hooked up to a battery, it will act as a short circuit and draw a LOT of current
(not a good sight). Capacitors need to be "charged up" first. This
is simply done by either putting a resistor (1k-ohm or more) or a test light between the
positive post of the battery and the positive terminal of the cap (with ground hooked up
to metal). After a few minutes, the capacitor will be charged up, and it can be
connected. Every time the capacitor is "drained" i.e the lights were left
on in the car and battery is dead, the capacitor should be DISCONNECTED, battery charged,
and then capacitor has to be recharged and reconnected.
Capacitors might help, but they do not take care of the fact that
your car's system is underpowered. They are a "patch" for a more serious
High Output Alternators
Another upgrade is a high output alternator and maybe adding a
secondary battery (for car off listening) to keep up with higher system's demands. This
should be done by someone who has a fairly good understanding of a car's electrical
system, since computers are designed to control the factory components.
Always keep in mind that when a car is running the batteries become
loads that take power away from your amps. The advantage of secondary batteries is
that when the car is off, you can listen to your stereo for longer periods of time.
Adding more batteries will not make your stereo perform any better
when the car is running. In fact, a second battery will steal power from the
electrical system when the car is running. A battery isolator should be used to
avoid batteries draining each other.
Replacing factory batteries with high performance batteries will
also improve power output. Companies such as Optima make batteries that take less
power to charge and have a higher output, placing lower demands on an electrical system.