Headlights dim and car idles at lower RPM after Sub install


Timbo74

CarAudio.com Well Known
Aug 10, 2019
121
14
Wisconsin
I did run a test with Volt meter though and my battery read 12.26V while the car was off and Alternator was at 14.4V. My battery is old though. Haven't changed since I bought the car. ( 4 years ) If the battery is weak does that effect the system? I have heard the ALT takes control after the car is started
The alt does not take control!!! Your battery still powers everything, the alt charges the battery!
If you have a dead battery, your car won’t run worth a shit at idle, if it even runs. When your driving, it runs better, Because your alt is doing its job. But because your battery is dead, your alt is under abnormal strain, trying to keep up.
Change your battery!
 
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naheed24

CarAudio.com Newbie
Oct 2, 2019
8
0
Calgary
Thanks. I took my car to a mechanic today to get the alternator tested. They said everything is working fine. It is the subwoofer that is putting a load on the electric system. He suggested to take it to where I installed and have them check the wiring. Also I forgot to mention, there is a POP sound from the subwoofer when I turn the ignition on. Is this normal?
 

Popwarhomie

Team Lethal Pressure
Jan 22, 2010
6,397
335
Florida
120 watts is the equivalent to turning your high beams on. Not much power at all. Most factory electrical systems can support 1000-1200 watts with no issues.

A subwoofer doesn't put a load on an electrical system. The amp does.

What amp are you running? Most quality amps have a turn on delay to rid the turn on pop.


Your battery resting voltage should be over 12.2 volts. I would take it and have it load tested.
 
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naheed24

CarAudio.com Newbie
Oct 2, 2019
8
0
Calgary
120 watts is the equivalent to turning your high beams on. Not much power at all. Most factory electrical systems can support 1000-1200 watts with no issues.

A subwoofer doesn't put a load on an electrical system. The amp does.

What amp are you running? Most quality amps have a turn on delay to rid the turn on pop.


Your battery resting voltage should be over 12.2 volts. I would take it and have it load tested.
Ok. I will take it to a battery store and have it tested. I am actually planning to buy a new battery as 4 years is a long time. I wonder how it starts the engine when it has become weak. Any recommendations for a good battery? About the Amp, the subwoofer I purchased has a built in Amp. Have a look

 
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naheed24

CarAudio.com Newbie
Oct 2, 2019
8
0
Calgary
I replaced the battery the battery and the headlights still dim. Anyone knows where to properly ground the subwoofer in Honda Civic 2012? The shop I got it installed have mounted the ground wire in the frame under the carpet. Any ideas?
 

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danielbea122

CarAudio.com VIP
Jul 29, 2019
333
36
Tampa
I replaced the battery the battery and the headlights still dim. Anyone knows where to properly ground the subwoofer in Honda Civic 2012? The shop I got it installed have mounted the ground wire in the frame under the carpet. Any ideas?
I have 2014 Corolla and my rear ground is grounded to the frame by a bolt that holds the rear seats to the frame.

Also make sure all paint/dirt/grime is removed from your ground point. You want to see bare metal at your ground point.
 

THATpurpleKUSH

Smoke weed everyday
10+ year member
Sep 30, 2009
7,326
478
Banging gears and passing queeers
So my car having stock LEDs are probably why I don't see any light dimming.
Quite likely yes.

Civics like op's have notoriously small alternators, like 70-80a. Combine that with an electronic load detector which is installed in nearly every Honda product since the late 90s and you have an electrical system that creates just enough power to keep the vehicle's systems running at idle, not a fraction of an amp more.
 

honkyg^2

these all go to 11
May 8, 2018
43
5
5h1th0l3 illinois
two of the first thoughts that go through any seasoned car audio hobbyist's mind concerning a lack in 12vdc power transmission should be;

1: are the terminals properly connected and tightened without galvanic corrosion or a substrate (paint, rust) hindering conductivity through connection points?

and 2: is there an addition of a big 3 upgrade included?
 
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