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9020 electrical issue

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What do you guys make of 15+ amps on the ammeter but only seeing 12.8V at the battery when running at high idle or higher on a 9020? Onan twin. Terminals are clean. Circuit breaker has been replaced.

I put a Battery Tender on it and will see what the ammeter reads after the charger says it's fully charged.

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I don't have a good answer other than to say that I am not real sure of that accuracy of these amp meters to begin with.

Did you take a reading at the ammeter with a digital meter to see if in fact there is 15 amps going in at that point?

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Fifteen amperes sounds reasonable to me if you had just used the starter to fire off the engine.  Usually 

it will charge like that until the battery voltage rises to it's topped off condition.    

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If a battery is fully charged , it should be showing about 13.5 V or more. I have done away with my ammeters and replaced them with voltmeters. All an ammeter really does, is tell you which way the amps are flowing. A voltmeter basically tells you what the condition of the charging system is, like maintaining 13.5 Volts when your running with your lights on for instance.


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I agree with burt.

Battery is not fully charged so voltage is "low".  When fully charged, the voltage should rise to about 13.5v as BLT stated, and the amp meter should read zero. 


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