The battery banks on Sea Rays are labeled Port and Stbd for whatever reason. I've always preferred numbered banks. Anyway, the new port alternator output rises slightly when the engine is running but does not charge the port batteries as the voltage at the battery does not rise. When the stbd engine is started, both battery banks show a charge. The system is such that the port bank powers the running systems and the stbd powers the house/convenience systems. I have tested the isolator (2 alt, 2 batt) and it tests without issue. The added electronics are powered at the helm where the port main buss except for the electronic shifter/throttle which was wired to the stbd bank. Thinking this was the leak, I moved these connections to the port bank. Still, the stbd alternator charges both banks. The emergency parallel solenoid appears to work properly as the standing battery voltage on each bank is slightly different when the solenoid is at rest. Can the parallel solenoid be leaking voltage through the relay? I'm now thinking I should bench test the emergency solenoid. I have reviewed the schematics carefully and see no cross over. Thoughts?