Mercruiser DTronic 2.8 Split Charge Diode

[salar]

Hello again, hopefuly someone on here knows how the Mercruiser alternators are wired up! I want to fit a split charge diode to take the alternator power feed and split it to two batteries. That bit is simple. The complicated bit is that the alternator feed goes into the electrickery box, where I believe there are two 60amp circuit breakers, and two wires come out of the box both of which go to the large positive terminal on the starter moter, and thence to the battery. Does anyone know which wire, or both, I should connect to the diode? Thanks in advance.

 

[DAKA]

if no one helps send me your email by pm and I will send you a 900 page service manual which includes the wiring diagram but its a bit of a dull read !

 

[salar]

if no one helps send me your email by pm and I will send you a 900 page service manual which includes the wiring diagram but its a bit of a dull read !

Thanks Daka, I have the wiring diagram from the installation manual but that does not help tell me how to wire in the split charge diode If there was one wire it would be easy...

 

[PaulGooch]

Thanks Daka, I have the wiring diagram from the installation manual but that does not help tell me how to wire in the split charge diode If there was one wire it would be easy...

Not sure why they use two wires Nev, so am guessing here a bit. It might be that the alternator has two independent outputs, so there would be no need for the diode.

In the absence of getting a definitive answer elsewhere, check that each wire outputs a charging current. Assuming that they do, leave one wire connected to the starter and see if you get a voltage reading at the other wire, without the engine running (check both wires).

If you get 12v ish at the wire that isn't connected, i'd say just connect both wires to the diode.

If you do not get a reading at the disconnected wire, forget the diode and connect each wire to a battery bank.

It might also be possible that one of the wires is a battery sense wire, in which case it won't output a charge.

Are both wires heavy gauge ?

 

[DAKA]

I dont know the 2.8 but it is referred to several times in the same manual as the 4.2L.

I believe you are on th eright tracks.

There are several wiring configurations within the same loom so care needs to be exercised and the wiring diagram for several 2.8L engines needs to be studied in order to understand why some wires appear to be duplicated.

 

[salar]

Are both wires heavy gauge ?

Last trip to the boat I spent some time staring at the alternator before taking the manual home to read. Now I'll have to go back and stare at the starter motor. Trouble is neither are easy to get to thanks both anyway