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How can you tell if a car audio capacitor is bad?

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  #1  
Old 04-06-2012, 03:38 PM
sponnerjhon's Avatar
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Default How can you tell if a car audio capacitor is bad?

Car audio system - 2 550 watt amplifiers, 2 10" subs, 2 250 watt 6x9s, 1 .5 farad capacitor, upgraded battery and alternator. After installing the capacitor according to the manufacturer's wiring diagram, I find that the car battery is draining while parked with the system turned off. The amps are powering off, the only apparent cause is the recently added capacitor. After removing the cap from the system, the battery drain appears to have stopped. Is this normal for a capacitor to drain the battery under these conditions, or could it be malfunctioning?
 
  #2  
Old 04-07-2012, 01:54 PM
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When it comes to these things you get what you pay for and the best bet is that your cap is faulty. Does it have a digital readout? That is probably not shutting off when the car is off. If your system is fine without the cap, as in your headlights don't dim at night, then just leave it out. Or replace it with another car battery, I would suggest the optima yellow top.
 
  #3  
Old 04-07-2012, 06:10 PM
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Simple way to test a capacitor using an OHM meter



Set your needle meter to an OHM scale, Example: Rx1
Touch your leads together and 0 ( zero ) out your meter with the adjustment wheel.

With wires off of the capacitor ( write down where they go first! )...touch the cap terminals ( red lead on left and black lead on right )...the needle should move away from the infinity ( probably left side ) and move slightly ( towards the right side ) and go back to infinity...reverse leads and ( red lead on right side and black lead on the left side ) on the cap and the needle should move away from infinity even further and then go back to infinity = a good cap. ( note - some caps have a built in resistor that you may read ) ( refresh page will start the animate picture again)

Animated picture help compliments of Danone Web Design


If the meter needle goes all the way over to the right side and stays there = a shorted capacitor.
( refresh page will start the animate picture again)

Animated picture help compliments of Danone Web Design
 

Last edited by z28pete; 04-07-2012 at 06:13 PM.
  #4  
Old 04-07-2012, 08:24 PM
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Check to make sure it's not staying on after you get out of the car. I had the same problem for a while. Turned out to be a bad ground wire that kept the capacitor on all the time. When you check it give it about 30 seconds before it shuts off. If it doesn't, check the wires. If that checks out okay. Then do the ohms test to see if the capacitor is defective.
 
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