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STBD Alternator charging Both Banks.

Discussion in 'Sea Ray Yacht' started by Thisisit, Aug 8, 2019.

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  1. Thisisit

    Thisisit Member

    Aug 20, 2004
    Port Severn, Ontario, Canada
    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?
  2. Capt Fred

    Capt Fred Senior Member

    Jun 22, 2009
    Long Beach CA
    My guess is that the new alternator is not sensing the actual battery voltage. The new alternator is slight different in configuration perhaps. Measure the voltage output on both alternators, to charge the batteries after the isolator you need more than 13.9 volts ( 13.2 fully charged +.7 for the isolator). If the new alternator is sensing the voltage at its output, it may be happy with 13.9 which really is not enough to charge the bank after the isolator.