What's new
Van's Air Force

The definitive Van's Aircraft support community! Buying, building or flying an RV? Join our exclusive family of mentors and enthusiasts!

Electrical issue and question

C

cgc

Member
Hi all,

I was out on a flight last Friday and on the last leg of a 2 hour flight, my volts dropped from their normal 14v +/- to about 12.7v and kept slowly falling. I turned off anything I could in flight and cycled the radio, Etc. but no help. I was able to land safely on battery power. When I got on the ground, I was messing around with additional electrical systems. When I pulled the EFIS fuse, the voltage came back online and everything was normal. Stopped and restarted the engine without issue. Later I checked all of the connections on the voltage regulator, the back of the AV-50001 and leads from the battery. The only think I could think of was that the 30amp main fuse had a poor connection in the socket and I bumped it when I was messing with the others.

I know others have had issues with the voltage regulator and my plane had the B&C replacement installed already. It was a cool day and I don't have any reason to suspect overheating but I guess it could be the VRR failing.

So on to my question... It looks like there's an open volt meter location on pin 2 of the 37 pin socket on the Skyview D1000. Pin 1 is the volt meter connected to the shunt downstream from the battery and generator (per the kit plans). If I were to connect a lead from between the generator and the VR to the pin 2 location, would I get a reading telling me if the issue was with the generator vs. the VR? Basically if there were voltage on pin 2 but not on pin 1, I would suspect the VR but if pin 2 was also showing low voltage I could assume the generator is the problem. Does this make any sense?

Any help would be appreciated. Thank you! Jonathan
2013 RV-12ULS
 
cgc said:
Hi all,

I was out on a flight last Friday and on the last leg of a 2 hour flight, my volts dropped from their normal 14v +/- to about 12.7v and kept slowly falling. I turned off anything I could in flight and cycled the radio, Etc. but no help. I was able to land safely on battery power. When I got on the ground, I was messing around with additional electrical systems. When I pulled the EFIS fuse, the voltage came back online and everything was normal. Stopped and restarted the engine without issue. Later I checked all of the connections on the voltage regulator, the back of the AV-50001 and leads from the battery. The only think I could think of was that the 30amp main fuse had a poor connection in the socket and I bumped it when I was messing with the others.

I know others have had issues with the voltage regulator and my plane had the B&C replacement installed already. It was a cool day and I don't have any reason to suspect overheating but I guess it could be the VRR failing.

So on to my question... It looks like there's an open volt meter location on pin 2 of the 37 pin socket on the Skyview D1000. Pin 1 is the volt meter connected to the shunt downstream from the battery and generator (per the kit plans). If I were to connect a lead from between the generator and the VR to the pin 2 location, would I get a reading telling me if the issue was with the generator vs. the VR? Basically if there were voltage on pin 2 but not on pin 1, I would suspect the VR but if pin 2 was also showing low voltage I could assume the generator is the problem. Does this make any sense?

Any help would be appreciated. Thank you! Jonathan
2013 RV-12ULS
Click to expand...

I just realized the first problem with my concept above. The output voltage of the generator is potentially greater than the 30v input the Dynon system allows. That seems to kill this idea.

Jonathan
 
The symptoms certainly sound like the B&C’s field breaker tripped in flight, and, back on the ground, you re-set it.
 
When I had similar charging problems I discovered my 30 amp generator fuse had some corrosion and looked like this...

IMG_5631.jpg

When I cleaned up the contacts and put in a new fuse my charging went back to normal. It had become corroded so slowly that I really didn't notice until it got pretty bad.
 
The output voltage of the generator is AC, not DC - the Dynon EMS wouldn't be able to sense it correctly.

I'd check all the wires going into the B&C AVC1 for signs of overheating, including right up at the spade terminal. I've lost two regulators (an old Rotax one and an AVC1) due to bad crimps on the wires, which caused the crimp terminals to eventually go high-resistance and burn themselves up. I know you said you checked the connections but did you look closely at the crimps themselves?

Bumping the 30A generator fuse back into a good connection, as you mentioned, also seems like a reasonable possibility. Remove it and look for signs of a bad connection there?
 
BobTurner said:
The symptoms certainly sound like the B&C’s field breaker tripped in flight, and, back on the ground, you re-set it.
Click to expand...
Thanks Bob! I bet you're exactly right. Just read the technical documents on AVC1 and now better understand the system. Couple additional questions/thoughts. Wonder why the generator would have got an over voltage? And when in flight, it looks like pulling power from pin 6 would reset the VR. Pin 6 appears to be looped over to pin 4 per the Vans wiring diagram. Pin 4 is feeding it DC voltage. Not sure if pulling the 30amp fuse would reset the VR?
 
j4cbo said:
The output voltage of the generator is AC, not DC - the Dynon EMS wouldn't be able to sense it correctly.

I'd check all the wires going into the B&C AVC1 for signs of overheating, including right up at the spade terminal. I've lost two regulators (an old Rotax one and an AVC1) due to bad crimps on the wires, which caused the crimp terminals to eventually go high-resistance and burn themselves up. I know you said you checked the connections but did you look closely at the crimps themselves?

Bumping the 30A generator fuse back into a good connection, as you mentioned, also seems like a reasonable possibility. Remove it and look for signs of a bad connection there?
Click to expand...
That's great to know about the AC coming off the generator. I did check all of the connections and didn't see any issues.
 
bbaggerman said:
When I had similar charging problems I discovered my 30 amp generator fuse had some corrosion and looked like this...

View attachment 84768

When I cleaned up the contacts and put in a new fuse my charging went back to normal. It had become corroded so slowly that I really didn't notice until it got pretty bad.
Click to expand...
Yikes! I'm thinking corrosion could be the issues especially seeing yours. A possible downside to blade fuses. Might be worth swapping (or at least cleaning) the full set at annual?
 
I have a B&C Regulator and in flight lost charging and cycled the master switch and everything returned to normal. That happened only once so far. I posted that issue.
 
You must log in or register to reply here.
Back
Top