Battery Load with New Amp - diyAudio
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Old 18th March 2009, 11:49 PM   #1
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Default Battery Load with New Amp

I had an amp for many, many years and it suddenly began draining my battery after a day or two of being parked. I thought it was the amp because when I placed an amp meter from the +battery to the power cable there was a 2 amp drain even with the car off and even with the remote disconnected. I bought a brand new amp thinking the problem was the very old amp and seeing as how it was a sudden issue. But, the new amp has the same problem in that there is a 2 amp drain, even when the remote wire is not even connected! I connect the power cable and the ground ONLY and there is the 2 amp drain. Btw, when I say 2 amps it is approximate because I have an analog meter...if that makes a difference. My battery was just checked out by AAA as being excellent, so that is working and my alternator is obviously working.

So, I'm out of ideas. There is obviously something beyond my electrical education, or I'm just overlooking something. Any ideas? Thanks a bunch!
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Old 19th March 2009, 12:22 AM   #2
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If you insert the meter in between the B+ terminal of the amp and the power wire that would normally be connected to the B+ terminal AND have no remote wire connected, you have 2 amps of current draw?

Does this amp have some sort of signal sense circuit or can it only be turned on by applying voltage to the remote turn-on terminal of the amp?

What make/model amp?
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Old 19th March 2009, 01:18 AM   #3
ppia600 is offline ppia600  United States
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Are you testing between the car's main power cable and the battery + or the amp's main power cable and the battery +. Try disconnecting (and taping) the b+ wire at the amp and test your wire again. Sounds fishy for two amps to do the same thing.




Otherwise, check to make sure the amp's ground is very solid. Some amps will try to power on if the ground is not tight, especially with the weird input circuits some have. Be sure to have the rca jacks and remote wire disconnected when testing.
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Old 19th March 2009, 01:42 AM   #4
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Do you have a large cap,or anything else connected?
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Old 19th March 2009, 02:46 PM   #5
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Perry - Yes. The meter is between the B+ wire and the B+ terminal on the amp, and there is a 2 amp draw. Nothing else is connected to the amp except the ground. When the ground is removed there is no draw. The voltage can only be turned on with the remote wire. There is no on/off switch on the amp. The power light is not on when the amp is drawing power. That's what makes this thing so fishy. It is a Phoenix Gold V752 250W RMS 2-Channel.

Ppia600 - I, too, was suspecting a ground issue. But I went back and tightened the ground screw (which was a little loose) but to no avail it still draws about 2 amps of current. This is the same ground point I have used for 8 years now in my car.

Digital Junkie - I'm not familiar with what a large cap is. But nothing else is connected to my amp except the ground and the b+ power cable. That's it. It draws 2 amps with a brand new amp after the old amp suddenly began draining my battery.

Does anyone have experience with/think it could be a problem with the wiring since it's older now? Could the wearing down of the wire insulation of one of the cables cause something like this? Or I'm wondering again, just like Ppia600 said, the ground is somehow at fault here?!

Thanks again for any help.
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Old 19th March 2009, 05:37 PM   #6
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Are you sure it's 2 amps and not 0.2 or 0.02 amps?

It's strange that you would get the same reading from two different amps.
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Old 20th March 2009, 10:48 AM   #7
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I am 100% positive it is 2 amps. On the 0.5 amp setting on my meter the needle is pegged. On the next setting, 50, it indicates the equivalent of 2 amps. I'm out of ideas on this one.
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Old 20th March 2009, 06:51 PM   #8
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Disconnect the amp from the power supply and short across the B+ and ground terminals of the amp to discharge the internal capacitors.

What is the resistance across the B+ and ground terminals of the amp. You may have to hold you probes on the terminals for a while for the reading to stabilize.
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Old 20th March 2009, 08:24 PM   #9
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I'm not really what "short across" is. Is that taking the B+ and placing it on the ground while taking the ground and placing it on the B+? I'll wait for your response on that to make sure I don't blow up my amp. But in the mean time I did measure the resistance between the B+ and ground with the amp disconnected from everything. While measuring Ohm and placing the positive probe of the meter on the B+ and placing the negative probe on the ground, the meter needle jumped in the left direction (opposite normal movement) and pegged there. I then measured amp flow and it was about 0.3 amp, but then the needle slowly went to 0. Taking the needles off, waiting, and then measuring the amp draw again the needle did not move from 0. I then measured the resistance again on the meter and the needle pegged once again all the way to the left. But once after that when I measured the amp draw, it did the exact same thing as before, it went to 0.3 amps and slowly went back to 0. So, measuring the Ohm for some reason resets something that makes a 0.3 amp draw. I tried this numerous times and the amp draw only indicates AFTER measuring the Ohm resistance.

I am thinking about going out and buying a new B+ cable and ground and basically measuring the amp draw from the battery using those new wires right there under my hood (i.e. not rewiring my entire car but seeing if there is something wrong with the wiring throughout my car). I would find a ground under my hood and connect the B+ wire to the amp right there under my hood as a test. If there is not a draw it is either a wiring issue or a ground issue with my existing setup. If the amp still does draw 2 amps...well, we'll go from there.

Thanks for your replies. I hope to learn what this "short across" stuff is so I can sufficiently discharge the capacitors.
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Old 20th March 2009, 08:43 PM   #10
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I wanted you to take a piece of wire and connect it between the B+ and ground terminals on the amp so the meter wouldn't see any significant voltage when you measured the resistance across it. Setting the meter to amps and placing the probes across the terminals did essentially the same thing.

If you place the probes on the terminals (meter set to ohms/resistance), what is the resistance?

Does your meter require that you move the meter leads to measure amperage?
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