Nippondenso alternator issues

[MrNomad]

How to test an alternator - go to Youtube

YOUTUBE has many videos on how to test diodes. Recently, the alt in my Chev died. Following the video on Youtube (searched HOW TO TEST DIODES), I was able to find the specific diode that failed and replace it from spare parts.

Cost for the repair was zero, education was priceless.

I'm not an EE, but my guess is the process is the same.

 

[932WT]

I'm trying to figure out if I have an alternator problem or not on my RV 10 0-540. I have a Nippondenso 021000-5411. Prior owner had new avionics put in by Stein Air who set the G3X voltage yellow caution threshold at 14.5. Mine was occasionally hitting 14.5 and flashing a yellow caution. Then it would drop to 14.2 where it was for most of the flight. My local mechanic, who didn't know it was an auto alternator when I asked him, said 14.3 or 14.5 was high. So do I have an issue or not? Is there a voltage regulator in this alternator? Should I just raise the yellow warning threshold on the G3x to 14.7 and see if it ever gets that high?

 

[bjdecker]

That's fine. Just change the caution range up by .1Vdc to avoid the nuisance triggers.

The set point for that alternator is 14.2Vdc. I have a Plane Power Alternator (essentially an ND Clone, Internally regulated) which runs along at 14.2Vdc in flight, occasionally will hit 14.6Vdc during initial start-up and when OAT is <60°F.

The primary battery can tolerate quite a bit higher, and most modern avionics will accept 11 - 30Vdc because they use internal DC-DC regulators/power supplies.
Edit: The AGM Type Odyssey PC680 can tolerate 14.4Vdc to 14.8Vdc, The LiFePo+ EarthX ETX680 will tolerate 13.9Vdc to 15Vdc(max)