View Full Version : how to wire two batteries two amps and switch.

07-11-2012, 09:51 PM
My boat already had this set up in the boat, except one amp is not even grounded so i guess it does nothing. speakers are 4 on the tower 4 in the boat and one amp. i think im going to redo it all to make sure it works right. sooooo how do i do it? what should go where?

07-12-2012, 12:20 AM
Provided you have no other components such as an ACR/VSR then follow this simple scheme and avoid all potential conflicts or mistakes.
All grounds are common and both battery grounds must be interconnected.
Nothing but a bilge pump/float switch if applicable and possibly the memory should be battery direct. Otherwise, every positive including the starter/alternator feed, helm buss and ALL audio equipment should access power from the output post of the dual battery switch.

Earmark Marine

07-13-2012, 10:06 AM
thanks for the response but i need this in wiring for idiots terms. im not following you yet....

07-13-2012, 10:20 AM
New battery GND gets hooked to original battery GND
Amp's GND gets hooked to new battery GND
Original battery B+ and everything else hooked there, except auto bilge B+, gets relocated to the switch "C" post
Amps B+ get hooked to switch "C" post
Switch post 1 gets connected to original battery B+ post
Auto Bilge stays on original battery B+
Switch post 2 gos to new battery B+

So, the only cable on the new battery B+ post is the cable going to the switch post 2. Same with the original battery, except the bilge auto B+ which is usually a brown wire with red stripe.