Cap question

LooseChangeRacing · Post by **LooseChangeRacing** » July 26th, 2006, 5:10 pm

Now when it comes to car stereo's i'm like most people, i can hook it up and it will work fine, it might not be the cleanest but it will work fine. Anyway upon talking to an installer that will be handling a big install for me he threw out this statement....you guys tell me...

A capacitor will help as long as the car is running....

If you run a cap and turn your stereo on (the car not running) it will drain and cause damage to the cap which will prevent it from ever being able to fully charge in the future if done multiple times.

ariesdude · Post by **ariesdude** » July 26th, 2006, 5:27 pm

you may need this in the future-

LooseChangeRacing · Post by **LooseChangeRacing** » July 26th, 2006, 5:38 pm

So you agree with me than....even if the cap was drained completly and the energy was just being drawn from the battery and going through the cap it would not cause damage to the cap becuase as soon as you started your car or even turned off the music the cap would fill with energy from either the battery or alt and would return to full charge no matter if you drained it or not.

I came to this conclusion logically for the reason of....what if your cap wasn't strong enough....on every high base note you drained the cap and if you had sucessive notes it would drain the cap then just drain from the battery through the cap....

MYTH BUSTED any Seconds on that?

ariesdude · Post by **ariesdude** » July 26th, 2006, 6:08 pm

Here's what i understand about this -

When you turn your stereo on - it turns the amp on which means the amp gets power from the battery (and battery gets some juice from the alt if the engine is running).

http://www.caraudiohelp.com/car_audio_c ... lation.htm
The cap is usually wired in parallel with the battery (with a fuse ofcourse) - so the cap always gets power from battery - if the cap is completely discharged then precautions must be taken for first time charging.

If the stereo is turned without the engine on - the amp will get power from cap and battery - the battery will take care of the cap in between huge bass notes.

Mazdaracer · Post by **Mazdaracer** » July 26th, 2006, 6:47 pm

a cap will only drain if
A) it's removed from the system
B) your battery is dead and cannot provide the cap with any power

so as long as the battery has power, the cap will too.

so by your *installers'* statement, any cap not installed, would never hold a proper charge anymore....?

a cap IS designed to charge and discharge multiple times...a resistor is used to fully discharge it when removed for safety, so it won't short out accidently...unless the cap is directly shorted out across it's terminals, (or discharged manually with a resistor) it's never fully discharged.

FlyVFR · Post by **FlyVFR** » July 26th, 2006, 11:13 pm

An Electrolytic capacitor in a parallel circuit will oppose voltage changes super quick! In car audio apps, it does this so the AMP won't choke when demanding more than the battery can supply at any given moment. So once it's in the circuit, it will stay charged at the supply level.

aries - I used many cans of BS spray in the work field.

V8KOMX3 · Post by **V8KOMX3** » July 27th, 2006, 1:14 pm

no worries man he ws bs'n you all the way. the only hazard I have seen from a cap is they can explode if not charged right before install