Dual battery charging

[tprice]

I re-powered my boat last summer with a F200 and while reading the manual I see that I can the motor up to charge the aux (electronics) battery off of the motor also.

What part do I need and how hard is this to hook up??

I have looked at the pics in the manual but is there anyting I need to look for??

[boats.net]

You will need 69J-81949-01-00 Battery Isolator lead. Connect to isolator lead on engine and to positive post of battery, be sure and install a 50 amp breaker or fuse inline.

Adding House Battery Using Aux Battery Isolator Lead

I have twin 2004 F150 each with starting batterys. Both battery's have switches and charge it's respective battery. I want to add a house battery (third battery). I understand each engine has Aux charging plugin and I have to buy the Battery Isolator Lead and direct it to the +post of the third battery. What is the part number? When I am running what are the amps to the starting battery(main Isolator Lead) and what will be the amps to the Aux lead? I understand the max amps at cruise is 35A per engine, don't know the idle amps. Is the charging discriminating(the weakest battery gets more amps) or are the leads regulated?
Thank you,jim

[tunnels]

I re-powered my boat last summer with a F200 and while reading the manual I see that I can the motor up to charge the aux (electronics) battery off of the motor also.

What part do I need and how hard is this to hook up??

I have looked at the pics in the manual but is there anyting I need to look for??

Your starting battery is a different to your house battery !
House battery should be a deep cycle type that takes a lot of slow draw off for long period with out damage !
The start battery is just that ,gives you high cranking amps for starting only ! Its always the first to be recharged cause if the motor dont go the batteries dont charge and if the motor dont go you are usually headed for trouble

The two can be interconnected but its the house to the start battery as a back up only!!! not the other way round .

Here in nz there are a couple of switch's that get mounted and everything runs through them, its all automatic or you can do it manually Batteries need to be as big as possible capacity wise and there mounting and ease of access is very important . A switchable battery volt meter is a good way to keep a check on the state of each battery at a glance
Not stuffed away in some dark damp hard to get to area where fumes can build up and the terminals get all corroded and then dont work just when you really need them .
If you are going to do it yourself seek professional advice and direction , sizes and lengths of cabling is a major factor in the systems efficiency and reliability