Wiring for an amp/sub in bassboat

[fast02ranger]

I'm looking for some help on wiring an amp and sub in my bassboat. I've got a 3 battery setup, one cranking, the other 2 trolling. How should I wire an amp to efficiently push 1 12" sub? It's just a 500watt Kenwood 2 channel amp. Currently I've got a Pioneer head unit pushing 2 sony 6x9's that I mounted in my rod lockers. Any help would be greatly appreciated.

[Havasu Hangin']

So you've got 2 6x9's and one 12" sub? :idea:
What model sub and amp?

[fast02ranger]

I've got 2 sony 6x9s and an audiobahn 12". The sony's i'm running off the head unit, my pioneer. Sorry, I'll have to get the model number off the amp, since it's at the lake house. I was thinking I might need a capacitor, but better ask someone who's done systems in boats with outboards.

[ROZ]

Depending on the amp, you could run it mixed mono.... That means you wire your 6x9's stereo(left and right channels from the amp) and run the subwoofer mono(check the manual for wiring config)..

[fast02ranger]

The main thing i need to know is the best way to hook it to the batteries, like which ones, starting or trolling? Where is the best place to ground the amp? Will it hurt the alternator on my motor? I know the motor, 225 Merc Optimax, has a 60amp alternator, but I don't want to burn it up because the amp is drawing to hard off of it. I've done several systems in cars and my trucks, but never in a boat. Thanks for any more advice..

[fast02ranger]

I ditched the kenwood amp and now have a RF200 4channel. Do I need additional batteries or a perko? Can running an amp hurt the electical system on my outboard? How can I wire the head unit up to where it doesn't always wear my battery down. It's hooked to the ignition switch now and cuts all the power to it when the key is off and I always lose my stations, time, etc. If I hook it up like I would in a car, it drains the battery over time. Any suggestions?

[ROZ]

Hook the red wire to your ignition or a toggle switch, and run the yellow wire(12v constant power to save your personal settings in memory) directly to the battery. it's the only way to save your settings.... You can wire both leads directly to constant power so you can play the stereo witht he key off, but you lave to make sure your headunit if OFF when not in use... Wire the amps power lead to your perko or directly to your battery and put a circuit breaker on it to keep your amps from draining battery power when stored... One amp won't put too much a strain on your outboard's charging system. You probably only need a 20 or 30 amp fuse on it...

[fast02ranger]

Ok, that sounds good. I assume the best place to ground the amp is at the battery as well? I've got room to put another optima battery in the rear compartment. I know on cars I try to keep the amp ground wire less than 18", but in the boat, the amp will be mounted under one of my consoles. Will that be ok to have a ground wire 8-10' in length? I know my questions probably sound a little dumb to you guys, but just want to get stuff right the first time. Thanks again.

[Havasu Hangin']

Will that be ok to have a ground wire 8-10' in length?
The reason you keep the ground wire as short as possible in a car is because the car chassis is the ground, and can carry much more current than any wire.
In a boat, the fiberglass cannot carry current, so all grounds have to run back to the battery (which is why most boats have grounding problems). Use the biggest cable you can for the job (terminate at a distribution block if necessary)- it will save you headache down the road.

[fast02ranger]

Thanks for all your help with my questions, I know what I need to do now. It's about 2 degrees out here today, but the garage is heated and it's time to get to work. Thanks again!

[ROZ]

Thanks for all your help with my questions, I know what I need to do now. It's about 2 degrees out here today, but the garage is heated and it's time to get to work. Thanks again!
Not bad, My brother called saying it was -17 in Boston Today... I told him it was too hot and I should have worn shorts... I also tole him to keep drinking that winter lager :D