amp killing car battery
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=95832
Printed Date: July 13, 2025 at 11:17 PM
Topic: amp killing car battery
Posted By: whiterob
Subject: amp killing car battery
Date Posted: July 23, 2007 at 1:23 AM
I had a sub amp that i used to run 2 subs off of. later my battery kept dying so i thought it was bad. i took out my fuse to my amp and it didn't die anymore. so somehow my amp was draining my battery. i looked at the amp and it wasn't on or running or anything so i couldn't figure out how the power was draining. anyone have an idea why my amp would drain my battery.
Replies:
Posted By: DYohn
Date Posted: July 23, 2007 at 9:44 AM
Assuming you mean the battery is going dead while the car is parked, there are several possibilities. 1) remote turn on is powered. 2) amplifier is bad. 3) wiring is bad. 4) battery is bad. 5) some other wiring or equipment issue not really related to the amp. ------------- Support the12volt.com
Posted By: whiterob
Date Posted: July 23, 2007 at 2:59 PM
it is not the battery because it was replaced and it still died. i think i narrowed it down to either the amp or the remote turn on.
Posted By: aznboi3644
Date Posted: July 23, 2007 at 5:38 PM
what amp is it?? How big is your alternator?? What gauge wiring do you have??
Posted By: mando2155
Date Posted: July 23, 2007 at 9:13 PM
Have you had your alternator output tested? I think theres some auto stores that will check it for free.
Posted By: sarcomax
Date Posted: July 24, 2007 at 12:04 PM
+1 on the alternator test. How many miles are on your car, and is it the original alternator? How much is your amp drawing? I would guess that since you were removing the amp from the charging system, that the alternator was able to charge the battery, without the unknown thumpin 2 subs running off the unknown amp drawing an extra unknown amount of juice.
Posted By: DYohn
Date Posted: July 24, 2007 at 5:14 PM
A bad alternator will not cause the battery to be drained while the vehicle is off. Yes, if the battery is being drained while the system is operating and the engine is running, the alt is a likely suspect. But I think the original poster is talking about his battery being drained while the vehicle is parked and the system is off, like over night? ------------- Support the12volt.com
Posted By: whiterob
Date Posted: July 25, 2007 at 2:42 AM
yeah i haven't been able to look at it yet but i am thinking that the amp is bad. it only dies when the car is off and i don't think it is the alternator.
Posted By: mjwood0
Date Posted: July 25, 2007 at 5:39 AM
If the car is off and the system is off when the battery drains, it has nothing to do with the alternator.
There are only so many things drawing power from your battery when the car is off. Disconnect the amp and verify that the battery doesn't drain. Once you've established that, hook it back up and probe the remote turn-on lead. Verify it works as expected. If so, you may have a wiring problem to the amp. You could always just connect the amp under the hood temporarily to verify that it's the amp and not the wiring.
Posted By: sarcomax
Date Posted: July 25, 2007 at 12:21 PM
I was only suggesting alternator test because I have had the joy of replacing one in my car because my weak little system was drawing just enough that the battery was not getting charged. I would park the car after work, and 10 hours later the battery would be dead. After a week of 6am jump starts, I tested the alternator and it was a whopping 50 amps. I only drove the car about 10 minutes each way, and every day my battery was dead. With such a short commute, I was not driving long enough for the car to just die on me, but long enough that I was pulling so much from the battery that I could not start the car. I am just suggesting that he does all of the free stuff before he goes and drops money to replace something that was not the root cause. If the alternator is fine, then great, I am wrong and admit defeat (I was married once, I am used to being wrong...)
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