Dual Battery Installation

[csuggs]

I am planning to install a second battery in the boat so that I can listen to the stereo without the motor running and have peace-of-mind that I'll be able to start the boat later on. I think I would like to wire the cranking battery to the starter, and the deep-cycle battery to my stereo and lights, without a selector switch. And from what I understand I can wire some kind of isolator device in the charging circuit that will charge either the weakest battery or work off a priority sequence so that when the priority 1 battery is fully charged, it will automatically switch to the priority 2 battery. Is this correct? Is there another way or better way? What have others done?

[wotan2525]

Sounds like you're on the right track.... The Blue-Sea add-a-battery kit has everything you need except for cables and terminals. It does have a switch but it's just an ON-OFF style that disconnects both batteries at the same time.... I've had mine for 3-4 years and it works great for both charging and isolating. I also have an on-board 3-bank charger (with 4 batteries hooked up) just to make sure that they are always all topped off.

I'd wire your starter, dash, and head unit to the "starting battery" and wire all your amps and lights to the "stereo" battery. You shouldn't have any problems....

http://www.buy.com/prod/blue-sea-7650-add-a-battery/q/listingid/63566882/loc/101/208409407.html