fwiw, I have a dual battery setup and a blue seas acr. I added a 3rd battery wired with the deep cycle stereo battery and ran the amps straight off that battery. I went with the same theory that if the hu isn't sending power, the amps should be off. granted there might be some current draw(not sure why), but I charge them after every outing so no biggie..

same scenario on my old supra only not a acr and it was fine..