Stereo cutting out - is it my amp?

I have a dual battery set up with Perko switch and an ACR. After about 3 hours of listening with the engine off, the stereo starts cutting out.

Would this normally be due to one of my amps heating up? I don't think it's my deep cell battery b/c when I get home to put it on the charger it's still at 65%. If it is an amp, how do I figure out which one?

Here's my setup:

Head Unit: MB Quart Nautic There are actually two of these in the boat (1 in the glove compartment which is a CD changer, and the other is at the helm). http://www.mbquart.com/nautic_accessories.html

In-Boat Speakers: There are 6 Kicker in boat speakers. Not sure on the wattage, but they're the typical 5" or so circular guys.

Amp #1: Kicker DX200.4. I assume this runs the in boat speakers but haven't followed the wires just yet.
http://www.crutchfield.com/p_20611DX...200.4&skipvs=T

Amp #2: MTX TC4001 Thunder - Class D. http://outlet.crutchfield.com/S-JKfF...er-TC4001.html

Amp #3: Planet Audio AC 1600.4, 4-channel mosfet. http://www.vickersav.com/index.php?m...oducts_id=2792

Sub: Kicker L5. http://www.crutchfield.com/S-42RW0AL...-06S10L54.html

Tower Speakers: There are 4 Phoenix Gold tower speakers in Roswell cans.

Its most likely your battery. If an amp gets hot it will go into protect mode until it cools down. The battery is probly running low and not supplying enough voltage to keeps the amps on. Take a multimeter and test em next time. Anything below 11.5 volts and your amps will most likely shut down. What type of batteries do you have?

My starter battery is this one: http://www.easternmarine.com/deka-12...arting-battery

My deep cycle stereo battery is this one: http://shop.advanceautoparts.com/web...%7CGRP60054___

You have a single 45 lb Group 24 deep cycle battery that may be between 60 and 70 amp/hours. Depending on how the stereo system is set up and how you use it, it may be unreasonable to expect more than three hours of play time. Also, depending on the size of the alternator, the ACR may not allow the deep cycle battery to get much of a charge after a serious discharge. If that has gone on for a while the battery may be degraded (no longer approaching the initial A/H capacity)somewhat by now. You probably need more battery capacity and help from an AC shore charger.
Like mentioned above, put a multimeter to task and take concise measurements to remove the issue from the realm of speculation.

David
Earmark Marine

I do put it on a trickle charger after every outing and make sure it's 100% before going out. I'll do some testing with my voltmeter and let ya know.

This may not be your case, but it took me about 4 months last summer of trouble shooting and re-wiring, checking voltage, batteries, speakers, etc before I stumbled on the cause of my speakers/amps shutting down. I was running them with the PERKO set to "Both". I now set it to either 1 or 2 and have never had that happen again. 1 if boat is cranked and 2 if engine is off.