Aftermarket sound system power

[drisso88]

Finally pulled the trigger on an upgraded sound system, and have everything coming in on Friday. Went with the Wetsounds MC20 head unit, going to install it on the lower right side of the helm, where the 12v and aux input are. 2 questions, and probably dumb ones. 1- can I use the power wire that originally went to the 12v charger to power the head unit? Seems like the easiest option and I'd think that runs to the house battery anyway. 2- where can I wire in the 0/1 ga for amp power to the DVSR? Originally thinking I would follow the power wire to the OEM Wetsounds amp and just wire it there, but for whatever reason that is wired to my start battery. I want this system to be able to run only off of my 2x100ah lithium house batteries, while leaving my start battery off. I also noticed the DVSR says 140amp max, and with 0/1 ga I'm going to be running a 250 amp fuze so not sure if that's going to cause an issue. I'm sure this has been done a bunch of times and I'm probably overthinking it, so any advice would be greatly appreciated!

 

[FSH 210 Sport]

The only dumb question is the one you do not ask!

As far as power source for the head unit goes, you’ll have to know what the required fuse size is. Perhaps run the power from one of the two ACC rocker switches on the dash? What about feeding the head unit from the stock sound system feed? If you feed it from the ACC rocker switch, check the circuit breaker size and adjust if necessary, New Wire marine carries those circuit breakers. I’d leave the stock 12 V power point / cigarette lighter socket for future use, if I understood your question correctly.

You are going to run 1/O copper wire to power the Amp with a 250A fuse? THHN 1/0 copper is rated at 170 A continuous. https://usawire-cable.com/wp-content/uploads/nec-ampacities.pdf 170A at 13.6 volts is 2,316 watts, peak to peak, I’m sure the RMS is probably a lot less??? And yes, I agree get it off the start battery and onto your two lfp batteries. The DVSR is not a factor, that 140 A rating is for what would flow through it as charging current from the engines. I think you have the DVSR power coming from one of the fuel pump hots?

I would install a circuit breaker for the amp feed. I do not know how the amp is configured, whether or not it has its own power switch or not, but the breaker could be used as a manual disconnect when the boat is not in use to make sure there is no draw on the lfp batteries when the boat is not in use.

 

[drisso88]

Ok so smaller size fuse/breaker for the main line, got it. I’m running OFC, if that makes a difference. I think I’m going to use the original amp wiring to put a bus bar in the helm, and I’ll use that to power the head unit. That’ll give me some options for power down the line as well. Just to clarify, you’re saying run the power to the amps directly from the house battery, skipping the DVSR completely? That’s what I wanted to do, and was gonna get one of those manual breaker fixes to ensure it’s not drawing power when the boat is off. To be fair, it’s always on the charger when I’m off the water but just as a failsafe.