[Darren Kerns]

Guys,
I posted a message yesterday in the electrical forum. Long story short, my RV8 is indicating low voltage on my Vision Microsystem. Yesterday, my wife helped my pull my cowling off and I double-checked all connections. Everthing looked good. I then adjusted my alternator belt and made it a little tighter. I then checked the nut on the pully and it seemed to be good and tight. Anyway, I fired it up and it went to 14.2 volts with nothing on. Then, I turned on my avionics master, strobes, position lights and it dropped to 12.3 volts. When I turned my landing lights, it dropped to 12.1. My warning light came on telling me of low volts. I have a 35 amp alternator with external voltage regulator. Even when I ran it up to 1800 rpm it was still doing it.

When I turned off my landing lights, then the volts go back to 12.6. I am lost at what to do next. I think my voltage regulator is working fine. It is mounted on the firewall to reduce vibration. Any thoughts or ideas would be appreciated. I am about to pull my hair out.

Darren Kerns
RV8 N214TK

 

[Ironflight]

How much equipment do you have on your Avionics master Darren? DO you have a complete list of all your electrical equipment and their steady-state loads?

 

[Darren Kerns]

Paul,
I have Icom radio with the FlightCom Intercom System from Vans and a Becker Transponder. That is is it. I kept it simple.
Darren Kerns
RV8 N214TK

 

[L.Adamson]

Had almost the exact occurence with a 9A. Made a landing at an airport and tightened the alternator belt, although it didn't appear too loose to start with. Voltage was back to normal on the ground run.

But once airborne, the voltage dropped again.
This time the alternator was pulled for a check; but I noticed some grey residue on the crimp connection of the alternator B-lead right at the alternator. With a slight pull, the wire seperated from the crimp; and had been arching. A new connection for less than a dollar fixed the problem.

BTW, neither of us two guys, made the original connection... And if all your connections, are for sure tight?

L.Adamson

edit: and what about the alt strapping to the engine case senario's, where it's not a good grounding situation due to some finish on the hardware?