Dual batteries

[Smeghead]

I have a very simple deck boat with a 135hp inline 4 cylinder Gm engine and one battery.
Ive seen the little dials that you can buy select between one/the other/both but how do you wire them up?

Is there some kind of thing that you plug the cables onto, then from there new cables to each battery?
The alternator has to charge both obviously

I want a battery purely for the purpose running the stereo and things when im stopped fishing or something, then have the main batt for starting the engine to get me home.

probly been talked about already, but, any help/advice?

 

[sarabande]

http://www.vetusweb.com/manuals/fil...ers_-_Inverters_-_etc/090300.04 r01 03-05.pdf

that gives you the link to the Vetus catalog, where they have some clear connectivity diagrams of the 1-2-Both-Off switch.

 

[Smeghead]

Thanks, I think i'll go with option 1

 

[Assassin]

You place a split charging relay, or one of the newer digital programmable split chargers in and connect to the alternator output, or between the batteries, depending on system.

The main engine battery is the priority battery, this is charged first and formost, surplus charge it then diverted to charge the auxiliary battery. As alternators rarely work flat out there is always surplus charge.

With the programmable uits you are offered a number of fixed and programmable options, and many have battery monitoring to give you the state of each battery.

 

[PaulGooch]

The switch you describe is not the best option, it requires user input, which if forgotten can lead to flat batteries. For a diagram and details of a better switch, see the wiring section of my website www.boat-fishing/co.cc

All IMO of course.