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alternater not charging battery - how to determine problem.

One of my (1988) 454 (350) engines is not charging the battery it is connected to. When running ~2000 RPM's I am getting a alternator reading of ~12 volts. My other engine is charging at 14+ volts. I have replaced the alternator / regulator and battery and checked the belt and electrical connections. I am a bit stumped as how to proceed to diagnose the cause of the problem. Any advice on how to proceed would be appreciated. The problem has persisted for over a year and I have been relying on my shore power and genny to keep the battery charged.
 
Has this alternator been bench tested?
Does this alternator require a field excite circuit?
If so, is this circuit being powered correctly?

Is the alternator chassis-to-engine-block Negative lead healthy and connected?

When checking alternator output, always take your voltage reading directly at the battery bank.


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I'd only add it is advantageous to also use a carbon pile (load tester) to ensure the wiring is healthy.
 
Has this alternator been bench tested?
Does this alternator require a field excite circuit?
If so, is this circuit being powered correctly?

Is the alternator chassis-to-engine-block Negative lead healthy and connected?

When checking alternator output, always take your voltage reading directly at the battery bank.


.
Thanks RicardoMarine and MakoMark for the suggestions. I was just out on the lake for the past 5 days so I will give your suggestions a try. The alternator / regulator is the correct one for the crusader engine and is new and not a re-manufactured one. The Battery is a brand new 8D Rolls-Surrette. I rechecked the wiring connections on the alternator this weekend and all was clean and properly connected (same as other engine) and the belt is new and working fine. I am not great with a hand held Amp meter so I will have a person knowledgeable take a look at it to check my readings. I will report back as to what we discover.
 
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