My boat (Formula 311) has 2 batteries and 1 switch; OFF, 1, ALL, and 2.

What is the correct position to use while running, charging (shore power), and haning out at the beach lsitening to tunes?
Thank you in advance.

the way i run mine is using radio #1,running i use both,docked overnight off.if you use 1 when sitting/hanging out listening to radio and battery dies you can still start boat with #2

I use both all the time, i actually have my amplifier and radio hooked up to one batter, but being that the switch is in all, it will be drawing off of a parallel connection from the batteries.

Batt. #1 for starting and hanging out, All when going on a good cruise to charge both up then back to #1, use batt. #2 for emergency starting only..

There's many schools of thought on this question.

Most people start the engine off of battery 1 and run all the "house" stuff off of a deep cycle battery 2.

Flip to 1 and start the engine and flip to 2 when you are hanging out listening to tunes. Flip to all when running so both batts get recharged. From what I've read, leaving the switch in ALL can be bad when you are not running the engine because the stronger battery will drain into the weaker battery.

I have worked on boats most of my life and know that running on both is not good, even new no two batteries are exactly alike the weaker will be seeking charge while the stronger will be getting a slight over charge shortening its life. A good rule is to run the odd #1 on odd days and the even #2 on even days, but far better is to install a battery isolator or combiner either of which will charge both batteries when the engine is running. You also can wire your charger into the circuit to charge both off a single circuit charger.

Phil

I had that setup in an SR357. I got the wiring diagram and it made NO sense. I rewired mine so I had two swithces that were wired like the PERKO diagrams and worked properly.