Low voltage

[Hondo]

I occasionally see a flashing voltage light which indicates low voltage which is usually caused by an alternator malfunction, belt slippage, or tripped breaker.

I think the low voltage indicator is set for 12.4 to 12.5 volts.  When I get the light, my JPI EDM 700 shows 13.5 - 13.7 and the ammeter is zero.

The breaker is not tripped, the belt is tight and the battery is fully charged and easily starts the engine.  

Do I have a problem?  If so, how should it be fixed?  Thanks

[OR75]

When do you see the low voltage ? In cruise ? 

[Piloto]

Check the rear connector of the annunciator panel. Spray contact cleaner and reinsert.

José 

[Hondo]

I have seen it in cruise and shortly after starting.  The last time I saw it was after starting, but increasing RPM did not clear it.

[Hondo]

Thanks Jose,  I will try that.

[ArtVandelay]

If that doesn’t work, inside there is a pot you can adjust it, sometimes it just gets dirty and needs to be cleaned.

[carusoam]

After starting, low rpm taxiing, this would be expected behavior...

Alternator output increases with rpm...

in cruise, showing 13+V the alternator is clearly working...

Follow-up may be learning more about the annunciator panel, proper settings and adjustment? (Is it working correctly)

If the settings are right, everything is working correctly... and it’s a momentary loss of a voltage reading... 

Use José’s advice... check both power supply and ground.

PP summary of what I have read on MS...

Best regards,

-a-

[N231BN]

The pot in the annuciator box is loose/dirty. Try a search on this subject, there are many threads that have discussed this issue in great detail.

[1964-M20E]

Verify the field wire and the ground wire to the alternator are in good condition and the connections are tight. 

[INA201]

13 hours ago, 1964-M20E said:

Verify the field wire and the ground wire to the alternator are in good condition and the connections are tight. 

+1