2nd battery connection

[cthru1]

On my 2004 F150 there is a second battery plug under the engine cover. This is illustrated in the owner's manual along with a wiring diagram for adding a second battery with optional part available from Yamaha. I contacted Yamaha customer service and was told that the part's suggested retail is around $70. I asked what it consisted of and the agent pulled the part and informed me that it is a piece of #10 wire with a bare end and terminal to connect to the mating plug under the engine cover and a battery connector on the other end. They further informed me that there is an isolation circuit built into this engine so that both batteries will charge when running and will be isolated from each other when the engin is turned off! Does anyone know if this is correct or working with this setup? It sounds like a wonderful inovation and a real no hassle rig to me. Thanks

 

[rodbolt]

Re: 2nd battery connection

hello<br /> works well<br /> its a feature that most large yamahas have had since the late 90's. but 70 dollars for some wire seems a bit still to me <br /> the isolation circuit is built into the rectifier/regulator assy.

 

[Ray Neudecker]

Re: 2nd battery connection

Yamaha tends to be pricey on wire.Local parts store will be a better choice.

 

[cthru1]

Re: 2nd battery connection

Mechanic at dealer where I got my boat says that if 2nd battery is connected this way it will only see arout 6 amps charge current from the 35 amp alternator. Seems to me both batteries should see full charge current and take what is needed as would be if only one battery was used. Anyone know about this? Is he correct ,or am I, or neither? Thanks

 

[rodbolt]

Re: 2nd battery connection

find another dealer<br /> if i can figgure it out i can scan the info from the electrical training manual. ask he tech to look at page 3-6 to 3-9 of the electrical systems training manual. and 5-17 of the 2005 marine technical guide. that coupled with the fact that charging current is determined by battery state of charge and electrical load, that system is a 35 amp output. either battery can take the entire 35 amp depending on its current state of charge. the regulator/rectifier actually splits the ac from the stator to achive isolation. in effect you have two charging systems with a common stator/rotor assy.<br /> so either ask your tech to take the 5 star vidieo course or find one that understands how the charging/isolation system works on that motor.

 

[cthru1]

Re: 2nd battery connection

Thanks rodbolt. I thought I was correct and i is jest a dum cerpenter!