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Alternator Over Voltage

Dayton Murdock

Well Known Member
Over the past few months my alternator light it has been flickering and the voltage has been going up from 14.6. Over this weekend it was 15.5 and I decided enough is enough so I took the cowl off, remove the alternator. I took it to a professional alternator shop and had them evaluate it. The alternator was without flaws but the technician told me that the condition I was experiencing is possibly a high resistance level in the wire circuit. I found the lug bolt on my battery was loose after tightening it the flickering light and high-voltage went away
 
Nice find..

Thanks Dayton, makes a good note to put in my troubleshooting category..always learn from the others!
 
What kind of battery do you have ?

Over the past few months my alternator light it has been flickering and the voltage has been going up from 14.6. Over this weekend it was 15.5 and I decided enough is enough so I took the cowl off, remove the alternator. I took it to a professional alternator shop and had them evaluate it. The alternator was without flaws but the technician told me that the condition I was experiencing is possibly a high resistance level in the wire circuit. I found the lug bolt on my battery was loose after tightening it the flickering light and high-voltage went away
 
Over voltage / Over current

Hi guys, I have a similar problem.
An RV8 with plane power alternator, Garmin screens. 110 hours of use.
Normally I see voltages of 14.3 and battery loading 3 to 7 amps.
But once in a while I get an alarm, 15.2 volts and +30 amps and even more... sometimes the amp meter goes out of scale.
My alternator fuse (60 amps) blew once! and my Alternator Field breaker popped out a few times too.
Took the alternator for inspection but they say it's fine... that my problem is o the wiring... already inspected everything and don't find anything wrong.
My guess is that having 15.2 volts clearly means the regulator is damaged (maybe fails when getting hot?)... just wandering who is sucking 60 amps! the battery?
It's very confusing...
 
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Hi guys, I have a similar problem.
An RV8 with plane power alternator, Garmin screens. 110 hours of use.
Normally I see voltages of 14.3 and battery loading 3 to 7 amps.
But once in a while I get an alarm, 15.2 volts and +30 amps and even more... sometimes the amp meter goes out of scale.
My alternator fuse (60 amps) blew once! and my Alternator Field breaker popped out a few times too.
Took the alternator for inspection but they say it's fine... that my problem is o the wiring... already inspected everything and don't find anything wrong.
My guess is that having 15.2 volts clearly means the regulator is damaged (maybe fails when getting hot?)... just wandering who is sucking 60 amps! the battery?
It's very confusing...

Check the resistance of the voltage sense line. Not sure what lead the PP uses as bus voltage sensing. A voltage regulator monitors the system voltage and will keep increasing the alt output until that voltage reaches it's target. If there is resistance on that sense line, the VR sees it as a low voltage and tries to raise it by going to full output and tripping breakers, system voltage reading high, etc. I chased this problem for a while and found the screw on the field CB had loosened and was the cause of high resistance in my case.

If there is resistance on the sense line, the extra output from the alternator shows up as excessive voltage on the main bus.

Seems the PP is notorious for connector issues, so possible that is the source of the resistance.

Larry
 
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