View Full Version : Running two batteries.. Got the switch now what? HELP!

03-17-2011, 12:14 AM
hey guys, i got a 93 prostar 205 and i want to install two batteries. I got a perko switch but there are a few questions I have. Since i listen to audio and have a power wire going from battery 1 to the amp does this mean i cant only listen to music while the switch is on 1? I want one battery for starting and other for audio. Im very puzzled though. Could i have the switch on ALL? Essentially what i want is for me to listen to music while the boat is running and for me to listen to music when the boat is off. I have a 600 watt amp for the 10' sub and a 250 watt for the 5 speakers. I need help though and what size wire should i run? 0 gauge or 4 gauge?

03-17-2011, 08:36 AM
have you looked at this thread?


03-17-2011, 11:23 AM
4ga is a little small, even for short runs off the battery. 2ga is good, no need for 0ga unless long runs, like over 10ft. My 06 has 2ga wire from the battery to starter and battery to instrument panel. I used 0ga from my batteries to the dist blocks and 4ga from the diat blocks to my amps. Could have easily gone down 1 size on both with no appreciable power loss.
Think of the Perko switch as 2 - in, 1 - out. So you hook all your loads and the charging lead from the alternator if it is separate from the starter motor cable to the "out" terminal and hook each battery to teh 1 and 2 "in" termainals.
Then everything runs off of whatever battery you've selected. 1, 2 or both. Also only the battery you've selected will charge off of the alternator. or both will charge if you have the switch to both with the engine running.
There are other ways to make the battery switching and charging more seamless, but the simple switch will still allow you to choose which battery to use and the ability to isolate a battery so you don't run out of juice listeneing to the stereo if that's a concern.