Amp shuts down at high volume, suggestions?

[OHLNautique]

I have one old Alpine 5 Channel running 8 6.5's (four tower, 4 interior) and one 12" Alpine sub ported. Two batteries, one solely dedicated to the amp and isolated via a perko. With the perko on "ALL" and the engine running the amp runs flawlessly. When I shut down the engine and isolate the amp battery, the amp shuts on and off at high volume. I have 4 gauge power and ground run to the battery. I'm suspecting a weak ground or needing bigger power wire. Any suggestions?

[78LS2]

RE: Amp shuts down at high volume, suggestions?

You are running 8 speakers and a sub off a 5 channel amp? how exactly do you have it configured, and how many ohms does it channel "see"? My guess is that you are giving it too much load, and it is not getting enough voltage so it is shutting off. Also, where are you getting the +12v rem from? Are you losing that source when you shut off the engine and isolate to only the amp battery, thus causing the amp to turn off?

If you had a bad ground or needed lower gauge power wire it wouldn't work all the time, not just when you switch to one battery.

[OHLNautique]

RE: Amp shuts down at high volume, suggestions?

4 channels are running at 2 ohms with 2 speakers per channel wired parallel. The sub channel is running at 4 ohms. The sub has dual 8 ohm voice coils wired parallel. The amp is rated to run in this configuration. The system runs fine with the engine off and battery isolated until I turn it up loud. When the amp does shut down, it is only for a second. Then it comes right back on. If I don't lower the volume it continues this cycle. Off, on, off, on until it's turned down. However, with the engine running, it will play at high volume and never shut down. It's not the remote. It's run straight from the head unit and the wire is only about 2 feet. I have seen grounds cause this problem but always in a car.

Anybody seen this problem from an amp at high volume? Could be a bad battery maybe?

[AuMDLST]

RE: Amp shuts down at high volume, suggestions?

The voltage draw of the amp is more than the battery can supply. When running you are supplying around 14.4 volts to the system. When not running your batteries will be around 12volts and when plating high volume especially with the sub firing you are dropping the voltage to cause the amp to go into a protect mode. You can see the voltage drop if you read at the amp with a meter.

[OHLNautique]

RE: Amp shuts down at high volume, suggestions?

What's the solution? I would think a Interstate deep cycle battery would supply one amp with plenty of power. Bigger wire? Third battery?

[Sinkoumn]

RE: Amp shuts down at high volume, suggestions?

Your five channel amp is the problem. Buy a JL 500/1 and use it SOLELY for the sub, that will solve your problem.

[OHLNautique]

RE: Amp shuts down at high volume, suggestions?

That's an expensive solution! I think that would make the problem worse. If the battery can't keep up with 1 5 Channel, it's definately not going to keep up with two big amps. However, the 500/1 in my truck is badass. It would blow the sub in my boat right out of the box.

[J]

RE: Amp shuts down at high volume, suggestions?

I would bet that your battery switch is on "1" all the time, so the boat alternator is unable to recharge the "2nd" battery which powers up your amp.

Your sub is wearing down your battery too quickly....a cap might help absorb the initial thump of the bass and may get you longer life out of your battery....if your battery is a decent one, then I would suggest just keeping your switch on "all" and get a third battery to boost the system when required. You can wire it in with an aditional switch.

[Sinkoumn]

RE: Amp shuts down at high volume, suggestions?

If I can run a simple setup with a JL 500.1, MTX 564, and a PPI 4125 off of 1 Optima blue top while parked and engine off I don't think adding an extra battery will solve your problem. Your just going to have the same trouble with two batteries to deal with.

You're amp is not doing the job, you will save your time and money by buying a seperate amp for the sub if you insist on pounding the sub hits when you are parked with the engine off and the alternator sitting still.

[OHLNautique]

RE: Amp shuts down at high volume, suggestions?

If the amp was not doing the job wouldn't I have the same problem with the engine running? It works great with the boat running. It also does fine with the Perko switch in "all" and the engine not running. (Forgot to mention that earlier and may have just answered my own question.)

[Cam003]

It’s your amp, when the sub hits it drops the voltage way to low for the amp to function. Your amp is just "CLIPPING" and when you turn it down the draw is much less. And when you turn the switch to two batteries I am sure it will run much longer and better because you are still drawing the same load but form a much deeper well of power. It is still the same voltage just a greater amount to pull from so it does not drop as hard as it would when on one battery. you don’t need another battery or a cap you need a separate amp for the sub if not the 500.1 JL then how about the 250.1 JL it is also a great amp and you can pick them up on ebay cheap.

Just a suggestion if you come to the forum asking for help don’t be so stubborn when people give advice.

[EarmarkMarine]

OHL,

The older Alpine V12 5-channel amplifiers are very good. Clean and reliable.

However, unlike contemporary mono amps that are biased for 2-ohms, the mono section of this amplifier was unforgiving of any load less than 4-ohms.

I'm unaware of an Alpine subwoofer with dual 8-ohm coils. It's more likely you've got dual 4-ohm coils. If that is the case switch from parallel to series and that should remedy the issue.

Temporarily disconnecting the subwoofer should isolate whether the problem is impedance or voltage.

David E.M.

[J]

Are you allowing your amp battery to charge up??

Your 2nd Battery (amp battery) is unable to charge up unless the switch is turned to all or "2".
Are you draining your amp battery, and not charging it up? Will an amp that can run on lower voltage help?......yes.....but eventually it will cut out too...

[OHLNautique]

It’s your amp, when the sub hits it drops the voltage way to low for the amp to function. Your amp is just "CLIPPING" and when you turn it down the draw is much less. And when you turn the switch to two batteries I am sure it will run much longer and better because you are still drawing the same load but form a much deeper well of power. It is still the same voltage just a greater amount to pull from so it does not drop as hard as it would when on one battery. you don’t need another battery or a cap you need a separate amp for the sub if not the 500.1 JL then how about the 250.1 JL it is also a great amp and you can pick them up on ebay cheap.

Just a suggestion if you come to the forum asking for help don’t be so stubborn when people give advice.

Don't mean to be stubborn, just trying to be thorough.

Earmark, your right, I think it's a dual 2 ohm wired series giving 4 ohms. I don't think anyone has ever made a dual 8 ohm sub. Duh. I know for a fact it's 4 ohm at the amp. The sub is about a three year old type S 12. I will definately disconnect the sub to help isolate the problem.

J: When the engine is running I have the switch to all. However, I am suspicious of a possible bad cell in the battery therefore not holding a charge.

I think I have several problems to test; bad battery/low voltage, weak ground, low impedance, bad amp. I hope it's not the amp but you guys may be right. I'll post what I figure out and if there are any more suggestions please post.

I'll try not to be so stubborn from now on. Yellow_Flash_Colorz:

[TravelinTrav]

Cant you swap which battery runs the amp, and which battery runs the engine around to see if a different battery will solve the problem? I am no expert, but that is where I would start, and see if the problem changes, unfortunately the problem would change to intermittent starting if it is a battery issue. How old are the batteries, and how long have you been running with your current configuration?

I would be more suspect of the battery myself, and possibly picking up a capacitor, to reduce the violent draw on the battery when the sub hits! I use deep cycle blue tops in my boat, with a similar configuration as you are running.