power, ground cables
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=122596
Printed Date: May 28, 2024 at 3:29 PM
Topic: power, ground cables
Posted By: shije
Subject: power, ground cables
Date Posted: July 09, 2010 at 4:37 PM
this might sound like a stupid question....but is the ground cable guage just as important as the power cable guage?.......for example: an amplifier with a (required) 4guage power cable with an 8guage ground cable........will the amp run properly?
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BLT
Replies:
Posted By: DYohn
Date Posted: July 09, 2010 at 5:54 PM
The ground cable must carry the same current as the main power cable so yes, it is just as important. More so, in that a poor ground connection will cause noise and other performance issues. There are two grounding related posts in the Hot Topics forum that might interest you. ------------- Support the12volt.com
Posted By: oldspark
Date Posted: July 10, 2010 at 7:10 AM
Definitelky AT LEAST as important. But in some ways, more important.
Burn out the power cable and things merely cease to function.
Burn out the grounds and you can cook equipment as the ground "return path" finds alternate routes or causes the alternator to output high voltages (relative to alternator ground = engine ground which - after burning out ground to chassis/body - has a much higher resistance to chassis/body....
Because ground handles more than just hi-power loads (like audio, winches, rally lights), I suggest ground wire gauge(s) EXCEED the largest power gauge.
It may as well exceed the alternator and battery total output since it is usually the cheapest place to reduce path resistance (the paths usually being shorted than active paths.
Posted By: shije
Date Posted: July 10, 2010 at 11:07 AM
so in the outcome that the alternator is sending higher voltage (for ex: 14.5volts)......would that cause the amp to run improperly and even cause the amp to clip & or make it difficult to set the gain
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BLT
Posted By: DYohn
Date Posted: July 10, 2010 at 11:49 AM
14.5 volts is the normal no-load output voltage for an alternator. If you are having trouble setting gains then perhaps there are issues with amplifier loading. Please post the make model and wiring configuration of your equipment and maybe we can help you. ------------- Support the12volt.com
Posted By: oldspark
Date Posted: July 10, 2010 at 8:28 PM
If anything, you'd expect the amp NOT to clip with a higher voltage.
It's running off a battery etc (ie, say 2V less than 14.4V) that clipping should occur.
Bit that's only for stuff using a "12V" rail. High power amps have their own internal DC rails that are higher (eg 35V etc) irrespective of the actual input voltage (within reason, and in theory...).
The two voltages that are important:
1. The battery voltage to ensure good charging and life (eg, ~13.8 to 14.4V)
2. The max alternator output voltage to ensure loads are not blown (eg, generally a max of 16V, but depends on load specs & may be lower).
Posted By: pngelykn
Date Posted: October 14, 2010 at 6:14 PM
oldspark wrote:
Definitelky AT LEAST as important. But in some ways, more important.
Burn out the power cable and things merely cease to function.
Burn out the grounds and you can cook equipment as the ground "return path" finds alternate routes or causes the alternator to output high voltages (relative to alternator ground = engine ground which - after burning out ground to chassis/body - has a much higher resistance to chassis/body....
Because ground handles more than just hi-power loads (like audio, winches, rally lights), I suggest ground wire gauge(s) EXCEED the largest power gauge.
It may as well exceed the alternator and battery total output since it is usually the cheapest place to reduce path resistance (the paths usually being shorted than active paths.
Don't forget that the power is fused, therefore, you pop the fuse. No big deal. A flaming amp from a cooked ground, however, is a real big deal. I've seen it.  ------------- 1 Panasonic HU
1 Power Acoustic Amp (sorry)
1 Amazing Box
3 Kicker CVR15s
1 Termlab
36 Hertz
139.5 Decibels
1 Big grin.
Posted By: oldspark
Date Posted: October 14, 2010 at 6:30 PM
I'm unsure what relevance fusing has to do with hefty grounds...
YES! Bad or broken grounds have been known to destroy on-board electrics, cook batteries etc.
But a fuse will NOT prevent a bad ground nor a ground from burning out.
FYI - read the date of the last reply before awaking threads. It's usually pointless (if not annoying) to reawaken long dead threads.... (Even if tempted - eg, yesterday I read that stater-motor solenoids were likely to not take more than 10A. 20A to 50A is more like it! But that was years cold....)
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