Help Me With The Wires On The Back Of An Alternator (Hitachi 12v-55A)

[GeneraiT001]

Hi,
I'm relatively clueless In my mind the start switch (on position 1) allows current from the battery to power the starter to turn the engine over (not sure how thats wired to the start button on the engine panel) - hope thats right So the alternator charges the battery - while the engine is running - what wires are connected to the back of the alternator and on which terminals? Its a Hitachi LR155-20 (129772 - 77200) 12v-55A.

 

[GeneraiT001]

Is it more or less this?

 

[dlochner]

It is common practice on production boats for the alternator output (B+) to be connected to the starter terminal. Done this way the alternator charges the battery through the cable from the battery to the starter and only charges the battery used to start the engine. Typically, this system has a 1-2-both switch as the main power switch. Look for the article on the 1-2-both switch on MarineHowTo.com for a deeper explanation.

Boats are built this way for several reasons. First it reduces warrantee claims because the wiring is simple. Because the wiring is simple, it is faster and cheaper to install the engine, and it ensures the start battery is always charged first.

 

[GeneraiT001]

It is common practice on production boats for the alternator output (B+) to be connected to the starter terminal. Done this way the alternator charges the battery through the cable from the battery to the starter and only charges the battery used to start the engine. Typically, this system has a 1-2-both switch as the main power switch. Look for the article on the 1-2-both switch on MarineHowTo.com for a deeper explanation.

Boats are built this way for several reasons. First it reduces warrantee claims because the wiring is simple. Because the wiring is simple, it is faster and cheaper to install the engine, and it ensures the start battery is always charged first.

Thanks Dave. Thats what I needed