Alternator whine

[Powder]

Anyone have any suggestions on eliminating alternator whine? First time test drive today after installing Q- form kicks and other system mods and the whine that has been there is much worse. Signal wires and most speaker wires run under the carpet, passenger side of console, to the trunk where the battery and amps are located. The output terminals of one amp are very close to the battery. I know its good to have short power leads to the amps but maybe 12-16" is too close.??
Any comments/suggestions??
THIA

MLH

 

[6APPEAL]

Where does the charge wire for your rear battery run? Is it close to any of your other wiring? Where is the ground for you battery in the trunk? What is your battery voltage like? From the sounds of it you are running dual batteries, so are your batteries the same age? What is the condition of you alternator? Have you had it tested?
Sorry for so many questions, but need some more information.
John

 

[Powder]

Thanks for replying John. The battery (1) is located on the passenger side, upper shelf of the trunk. The pos. cable runs thru the floor, thru the frame to the engine compartment. Alternator was just rebuilt although it was working with 62K miles on it. Voltage with engine running is 14-14.2ish volts. All signal and speaker wires run from head unit to the trunk on the passenger side of the console except one speaker wire that goes to the driver side kick panel.
One change I made when installing the kicks was the addition of an external crossover which is temporarily wired for the power, grnd, and turn on signal. I hooked those wires directly to the battery just for my test drive, then disconnect so crossover doesn't remain powered up until I finish wiring it in.
Battery is grounded to the body and I have extra grounds from the frame to the engine and trans. I don't think thats a factor, but who knows?
I just wonder if having one of the amps located within a foot of the battery could be causing it.
What do you think?

MLH

 

[6APPEAL]

Sounds like you thought out your signal cable placement, so I don't think that is the problem. Sounds like your alternator is fine also. I normally wire my crossovers hot all the time to cut down on turn-on thump. The placement of the x-over might be causing the problem. Sometimes your speaker wiring can pass noise to your signal cables. But, I've only seen this happen with cheap wiring and cables.

When most people put a 2nd battery in the car for a stereo they end up creating a ground loop, which causes motor noise. Try running your 2nd battery ground to the frame. I did not think to ask where your trunk equipment was grounded, but it is best to run it to the same location. You could also try running a ground from your dash equipment back to the trunk with the other equipment. It is also a good pratice to have both of your batteries close to the same age so they discharge and charge equally.

I have never had a problem with the amp(s) being mounted close to the battery. My sub amp has only about a foot of power lead. I don't like any voltage drop .
John

 

[David65]

Had the same problem on a car once, found that by running all the grounds directly to the battery eliminated any alternator noise completely. Before, the radio was grounded to the factory wiring in the dash and the amp to the trunk floor. Don't know about your setup tho with the battery in the trunk...

David

 

[Powder]

I only have one battery and the ground leads from both amps and the crossover are connected to the battery. I was hoping this might be the problem. One other change I made was securing the speaker wires and patch cord from the head unit to my behind the seat crossbracing which is connected to the body like my battery ground. I doubt this is the problem because the speaker wires are good quality 12GA and the patch cords are not cheapies. I appreciate the input from you guys. I'll try moving wires around in the battery area to see if i can isolate the source.
Thanks again.

MLH

 

[6APPEAL]

Whoa , you only have one battery and did not run the ground to the frame. I'm suprised you have not burned up anything. Please run that ground to the frame with at least a 4 guage ground cable. Every battery reloacation kit I have seen recommend running the ground to the frame. I think you just found your problem.
John

 

[Powder]

Methinks you're on to something, John. I was never too comfortable with that ground arangement, not sure why I did it that way. Ground will go to the frame this weekend.
Also, I realized my electronic crossover mount is not isolated from the chassis which, according to the Crutchfield manual, can also cause interference.
Thank you very much for all of your advice! Who knows how much damage could be caused with that setup.

MLH

 

[grocerygetter]

yep...you've got a bad ground. Ground the battery to the frame. Many people don't realize that if your ground wire is longer than your positive wire to any component you could have current problems. That could be problems as critical as burnt electronics or as minor as noise. Electrical current runs across your ground just like your power wire. If you 100amps going across your power wire, you have 100 amps going across your ground.

 

[Powder]

Grocerygetter: Thanks for the input. I have already changed
my groundwire to the frame which eliminated 90% of the whine.
I'm close to having it solved. Thanks again for the advice.
MLH

 

[grocerygetter]

OUr cars are old...some of your whine could be bad grounds in our dash also.

 

[6APPEAL]

I agree with you. I've have very good luck running the grounds for the dash equipment to the rear with the other equipment.

 

[Powder]

Your comments on the effects of the grounds at the head unit has me thinking. I used an adaptor that connects my player to the factory wiring. Wherever that ground connection is located and the wire getting there, may not be stout enough for my aftermarket higher power unit.
What would you do to improve the ground circuit at the head unit and not violate the power vs. ground wire relationship mentioned above? (This is like taking an electronics course.)
Any ideas? I think this info you guys are providing may be helpful to other confused souls besides me.
Thanks for all the help, the story continues.

MLH

 

[grocerygetter]

try disconnecting the ground wire from the harness...make female connectors work great because then you can plug it back together. Try grounding it straight back to the firewall...plenty of sheet metal next to the heater vents behind the passenger side carpet. Make sure to get a clean connection. If the sound doesn't go away...plug the ground back where it was. Man, alt whine stinks...I've had three extensive SQ competition cars. Two of the three whined ...barely...but they did. We hunted for ever. The 99 accord was the airbag computer under the radio...isolated with lead and rocked on. The 88 accord was the components in the car (Audio Control...some are good...this one made noise).
Cheap-junk RCAs could also be picking up noise if you are amping your highend. If you are only amping your subs...don't sweat it.

 

[Powder]

GG
I'll try improving the ground to the head unit like you suggest. It seems to be worse when playing the radio vs. recorded media. (minidisc) I'm not totally convinced my wiring between amps and battery isn't to blame because of the close proximity of those components and the speaker wires. As you can see this is a slow moving project for me. I move from one project to another while the car sits in the garage resting up for the good weather coming. When I get this resolved I'll post the results so someone else might benefit.
I am amping the upper frequencies.

mlh

 

[grocerygetter]

worse when playing the radio could make sense that's it's a bad ground to the head unit because it's trying to ground through the antenna.