I have an 02 31 sonic with frig. and it works with the shore power and also off the galley power when out on the water . my question is should I set the battery switches to "both" for the 2 engines or run both engines off 1 battery and the frig. off the other. left the galley power switch "on" for the frig. when docked at a resturant for about 5 hrs and both batteries where dead ?

You need better batteries. My fridge will run longer than that on one battery. I use both batteries when the engines are running, then switch to one when they are off. That way you will always have 1 fresh battery to start the motors.

I like the Optima batteries

I second Go4Broke's process. That works for me as well. Have never not been able to get started due to dead batteries. If you don't already have one, I recommend that you buy a portable battery pack to keep in the boat (don't forget to keep it charged up). Those little things come in handy...

That reminds me, I need to go charge my jump box.

The jump boxes are a must.

I loaned mine to a fellow poker runner to start his brand new Nortec with a pair of 1500's. I must admit, I laughed just a little bit.

04 386 WITH gen, still for sale. has bettry chager.

For what it's worth, my boat manufacturer told me while running to run each engine on it's own battery in order to charge the batteries properly. I always shut the battery off that my amp is not wired to when moored and listening to tunes, but I now run each engine/battery independent of each other rather than on the both setting. Not sure if that information varies by how things are wired by the manufacturer, but thought I'd share what I was told.