Upgrading Your Charging System
This is a popular topic and many people think there are simple answers. The answers may be simple but the solutions are often very expensive. Some of the problems and solutions will be covered on this page.
Dimming Headlights:
This is the most common complaint for those who have installed high-power sound systems in their vehicles. This problem can sometimes be overcome by installing an alternator rated for higher current but this isn't always the case. Some alternators have a slight regulator lag and, even though the alternator can produce the required current, it doesn't react quickly enough to prevent short-term dimming. This can vary between various alternators, even if they're rated for the same current. In some instances, the owner of a vehicle will install multiple alternators. The OEM alternator will power the vehicle's electronics and charge the OEM battery. One or more alternators will power the amplifiers and charge auxiliary batteries. Since the amplifiers aren't drawing current from the OEM system, the lights cannot dim.
If you replace incandescent headlamps (standard and halogen headlamps) with HID headlamps, the headlamps won't likely dim. HID lamps have a ballast that acts like a regulator. This regulator will keep the voltage/current constant and will therefore prevent dimming.
In some instances, you may be able to use a voltage regulator for incandescent headlamps. This is safer if you only do it for the low beams OR the high beams. This will prevent the loss of light if the regulator fails. A regulator like the Accuvolt can keep the voltage constant. In the near future, LED headlamps will be available. These will be easier to regulate because LEDs don't need the full voltage of the charging system.
Alternators:
As was stated on the charging system basics page, the alternator supplies all of the power to all of the electrical accessories (amplifiers, lights, power windows, power seats...) as long as the engine is running (unless the current demand exceeds the capacity of the alternator).
Many people want to know when they should replace their alternator. The short answer is... when it fails. If you just want the battery to remain charged and your present alternator is keeping it charged, it's doing its job. If you want a system to be as close to perfect as possible and money is no object, replace your alternator when you install the amplifiers.
Multiple alternators was previously mentioned. It's very difficult to install multiple alternators on many of the newer cars because there simply isn't any available space. For older vehicles and trucks, there are more options. You can buy brackets for multiple alternators. THIS is one example.
Extra Batteries:
Extra batteries are great if you want to listen to your system with the engine off. While the alternator is charging, the extra batteries will only draw current which could otherwise be going to your amplifiers. For proof, all you have to do is measure the voltage while the engine is running. It should be approximately 13.5-14.4 volts DC. Then turn the engine off and measure the battery voltage again. Now it'll be around 12-12.5 volts. Whenever the voltage at the battery is near 14 volts, there is current flowing into the battery. The only time that the battery supplies current with the engine running is when the current capacity of the alternator has been exceeded. When that happens and the batteries are the source of power, the voltage supplied by the batteries will be significantly less than the voltage of an alternator that's capable of supplying the required current.
One Farad (and larger) Capacitors:
Large, one Farad, capacitors only help to maintain the charging voltage for a tiny fraction of a second under high current demand situations. They won't really solve your current supply problems if your alternator can't keep up.
NOTE:
Capacitors DO NOT increase the charging system's voltage.
( Borrowed from BCAE1.com...Somehow i missed some posts)...LOL
M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!