Twin Alternators

[Oil Gypsy]

Hello,

I have a Grand Banks 36 with twin Ford Lehman engines. When running both engines the port alternator always indicates it is charging the batteries, usually around 25-30 amps, the starboard amp gauge seems to indicate a small discharge +/- 5 amps. Even when running the starboard engine alone the gauge rarely indicates that it is providing a charge, I've changed the starboard alternator but the same condition exists.

Can anyone explain what seems to be happening and suggest some tests to find out what is going on and whether it is a gauge issue

Thanks

 

[CharlieJ]

Put a clamp meter on alternator output cable.

 

[koliver]

Some are set up so that one alternator charges House, the other charges start?

 

[DavidM]

There are numerous ways of rigging up two engine alternators. Also lots of house and starting battery configurations. It is vey difficult to answer without knowing how they are currently rigged.

I think Nigel Calder's book has some suggested setups.

David