Seperate isolated battery for assesories

[steveinsac]

I want to add a battery to the bow of my 14' boat to help with wieght distribution. Basically I was going to use this battery for my radio with an equalizer and my bilge pump. It is a large everstart MAX 29 875 cranking amps with 205 reserve marine battery. Can I just hook up the possitive from the fuse panel and the ground wire to the battery without connecting it to the motor? The yamaha 2 cycle 50hp motor will have it's own smaller battery(everstart) in the back of the boat. About how long can you play a 200watt radio/add on equalizer? The 2 reasons for having this extra battery is to wiegh the bow down and not drain the starting battery.

 

[ricksrster]

Re: Seperate isolated battery for assesories

Some folks will tell you to use a combiner, but this is how I did mine. You can run a 12V+ from the 2nd battery to your fuse block and a ground from the -post of the battery to your ground bus:

 

[Silvertip]

Re: Seperate isolated battery for assesories

By hooking the positive terminal of the auxiliary battery to the fuse panel you would automatically connect it to the charging system of the engine and consequently would place it in parallel with the start battery. The problem with that is if you use a wire gauge that's too small, you might melt some wires when you start the engine because it will draw from both batteries. That is a very risky connection method. If you really want the second battery isolated, install a dedicated fuse panel for that battery and wire the accessories to it rather than the existing fuse panel. As an alternative, you could wire the accessories directly to the second battery and use in-line fuses for each device. Simple, effective, and safe. You would need to charge that battery with an on-board charger or a portable charger.

 

[ricksrster]

Re: Seperate isolated battery for assesories

Or run the acc. wire from the engine post on the switch. Since a new wire runs from the rectifier/regulator, the original that connects the rect/reg to the solenoid would have to be disconnected. After the motor starts, switch to 2nd battery. Make before break or not would not matter because alt. is always connected to isolator which is always connected to the batteries.
When motor is shut down everything can run off 2nd battery. Switch to 1st battery to start.

 

[jtexas]

Re: Seperate isolated battery for assesories

On my boat you'd just disconnect the fuse panel from the cranking battery, connect the aux batt (+) there, and reroute your aux grounds to the aux batt (-). Obviously, that's not a factory wiring job...............