Subwoofer amp draining battery ?
Thread Starter
Pro
Joined: Mar 2004
Posts: 553
Likes: 6
From: Northern VA
Subwoofer amp draining battery ?
Can an audio power amp wired to the battery drain it while the stereo is off ?
I connected my subwoofer power amp power leads directly to the battery positive and negative terminals and connected the remote turn on power cable to the radio which only supplies power when the ignition is on. The amp should allegedly be dead until I turn the radio on.
My battery doesn't see to keep a charge for more than 2-3 days then it dies.
How do I check to see if the amp is causing a current leak?
Thanks
I connected my subwoofer power amp power leads directly to the battery positive and negative terminals and connected the remote turn on power cable to the radio which only supplies power when the ignition is on. The amp should allegedly be dead until I turn the radio on.
My battery doesn't see to keep a charge for more than 2-3 days then it dies.
How do I check to see if the amp is causing a current leak?
Thanks
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
There is a number of ways to attack the problem.
Connect a DC ammeter in series with the stereo when it is off and see if it is drawing any current.
Or you can disconnect the stereo and see if the battery holds a charge longer than 3 days and the problem goes away.
You can also measure the total current from the battery cable and see it that is under 50 milliamps. A normal value would be 25-35 MA.
To drain a battery in 3 days you would have to be drawing a lot more than 50 MA. If you are not the battery might be defective.
Connect a DC ammeter in series with the stereo when it is off and see if it is drawing any current.
Or you can disconnect the stereo and see if the battery holds a charge longer than 3 days and the problem goes away.
You can also measure the total current from the battery cable and see it that is under 50 milliamps. A normal value would be 25-35 MA.
To drain a battery in 3 days you would have to be drawing a lot more than 50 MA. If you are not the battery might be defective.
Last edited by pcolt94; May 13, 2009 at 10:37 PM.
Instructor
Joined: Mar 2009
Posts: 136
Likes: 0
From: South Carolina
When having subs in your car, its always a good addition to have a capacitor to take the strain off of your alternator.
http://www.bestbuy.com/site/olspage....=1172880157454
If your lights dim when your subs hit, you need a capacitor.
http://www.bestbuy.com/site/olspage....=1172880157454
If your lights dim when your subs hit, you need a capacitor.
Team Owner
Joined: Jan 2003
Posts: 20,306
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From: Summerland B.C. Canada
Thread Starter
Pro
Joined: Mar 2004
Posts: 553
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From: Northern VA
Sorry for the delay in updating the thread.
The amp was draining the battery. I disconnected the amp ground wire from the terminal then re-connected my DC Ammeter as instructed between the ground wire and the terminal.
The ammeter immediately registered a minus -0.68v reading. I checked the amp connections and even replaced the positive and ground cables going to the amp but the ammeter still registered the same reading every time I checked.
Gonna need to buy a new amp so I ain't got bass now.
The amp was draining the battery. I disconnected the amp ground wire from the terminal then re-connected my DC Ammeter as instructed between the ground wire and the terminal.
The ammeter immediately registered a minus -0.68v reading. I checked the amp connections and even replaced the positive and ground cables going to the amp but the ammeter still registered the same reading every time I checked.
Gonna need to buy a new amp so I ain't got bass now.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Sorry for the delay in updating the thread.
The amp was draining the battery. I disconnected the amp ground wire from the terminal then re-connected my DC Ammeter as instructed between the ground wire and the terminal.
The ammeter immediately registered a minus -0.68v reading. I checked the amp connections and even replaced the positive and ground cables going to the amp but the ammeter still registered the same reading every time I checked.
Gonna need to buy a new amp so I ain't got bass now.
The amp was draining the battery. I disconnected the amp ground wire from the terminal then re-connected my DC Ammeter as instructed between the ground wire and the terminal.
The ammeter immediately registered a minus -0.68v reading. I checked the amp connections and even replaced the positive and ground cables going to the amp but the ammeter still registered the same reading every time I checked.
Gonna need to buy a new amp so I ain't got bass now.
Did you really mean -0.68 amps and just made a typo. And did you have the meter set to the amp range with the proper setup of leads with YOUR specific meter.
Before you run out and buy a new amp lets make sure your test results are valid for what you are trying to test. Even if you are right or wrong about the amp I would do the secondary test by disconnecting it, going 3 or 4 days and see if you don’t have the discharge problem.
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Thread Starter
Pro
Joined: Mar 2004
Posts: 553
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From: Northern VA
Hi Pcolt,
Thanks for your post. I used a 6 dollar ammeter from harbor freight and I put it on the 200 DCA setting. I'm pretty sure I just typed volts when I should have typed amps.
I actually have 2 amps in there. One of them is the sub amp and the other powers the door speakers. The door spekaer amp showed a 0.00 reading but the sub amp was the one that sparked a bit when I re-connected it to the ammeter. It read -0.68 something :-). I wondered anout the minus but thought it unimportant. Was it ?
I charged the battery last night at 10 amps for 10 hours. The true test will be when I crank it this morning. It hasn't lasted overnight yet :-) What a thrill if it actually starts right up.
Thanks for your post. I used a 6 dollar ammeter from harbor freight and I put it on the 200 DCA setting. I'm pretty sure I just typed volts when I should have typed amps.
I actually have 2 amps in there. One of them is the sub amp and the other powers the door speakers. The door spekaer amp showed a 0.00 reading but the sub amp was the one that sparked a bit when I re-connected it to the ammeter. It read -0.68 something :-). I wondered anout the minus but thought it unimportant. Was it ?
I charged the battery last night at 10 amps for 10 hours. The true test will be when I crank it this morning. It hasn't lasted overnight yet :-) What a thrill if it actually starts right up.
Instructor
Joined: Dec 2013
Posts: 106
Likes: 7
From: Chandler AZ
What was the outcome?
Hi Pcolt,
Thanks for your post. I used a 6 dollar ammeter from harbor freight and I put it on the 200 DCA setting. I'm pretty sure I just typed volts when I should have typed amps.
I actually have 2 amps in there. One of them is the sub amp and the other powers the door speakers. The door spekaer amp showed a 0.00 reading but the sub amp was the one that sparked a bit when I re-connected it to the ammeter. It read -0.68 something :-). I wondered anout the minus but thought it unimportant. Was it ?
I charged the battery last night at 10 amps for 10 hours. The true test will be when I crank it this morning. It hasn't lasted overnight yet :-) What a thrill if it actually starts right up.
Thanks for your post. I used a 6 dollar ammeter from harbor freight and I put it on the 200 DCA setting. I'm pretty sure I just typed volts when I should have typed amps.
I actually have 2 amps in there. One of them is the sub amp and the other powers the door speakers. The door spekaer amp showed a 0.00 reading but the sub amp was the one that sparked a bit when I re-connected it to the ammeter. It read -0.68 something :-). I wondered anout the minus but thought it unimportant. Was it ?
I charged the battery last night at 10 amps for 10 hours. The true test will be when I crank it this morning. It hasn't lasted overnight yet :-) What a thrill if it actually starts right up.
Cruising
Joined: Oct 2024
Posts: 12
Likes: 2
I think this is my problem with my C5 Corvette. I have a I’ve had a alpine subwoofer amp for 15 years or so (sounds great) but and struggled with the battery dying maybe for the last five years, I’m gonna do the same thing and put a meter in series, and I was thinking what alternatives do I have?Put a switch in the circuit so that when I shut the car off, I also switch off the connection between the battery positive connection and the amp?Would love to know what you did, buddy?Thanks.
The amp, if working correctly, shouldn't have any appreciable current draw when off. If it does, there's an issue with it, and amps are cheap enough now to toss it and get a new one vs repairing it. Ensure the remote wire isn't turning it on when the car is shut off. If so, find a different remote turn on source and trace down why that initial circuit is energized when the car is off.
Earlier in the thread someone said to use a capacitor- ignore that advice entirely. Standard 1-5 farad caps are worthless, bordering on harmful.
