Narrative:

During my scan I noticed my volts reading approx 12 volts and a slight draw on the amps. I noted my alternator circuit breaker popped. I turned off the alternator switch; turned off the avionics switch; reset the circuit breaker; and turned the alternator switch back on. The volts read approx 13.5 and amps were very high at approx 28 amps. The circuit breaker tripped again and I started heading to the nearest airport. Shortly the engine rpms dropped from around 2;500 rpms to 1;700 rpms and shortly after that then engine quit. Since I was in gliding distance of the airport I did not attempt a restart. After landing and parking the airplane I called and left a message with the owner of the aircraft. In the meantime I tried to do some trouble shooting. In attempting to restart the engine; the battery was weak so I pulled the battery and I was able to find someone who could put it on a charger. Several hours later; after I was able to talk to the owner of the airplane; he arrived at the airport. We reinstalled the battery and the owner started the airplane. Everything seemed to check good. We ran it for awhile; volts and amps were well within normal range. The magnetos and electronic ignition systems tested ok. We decided it was ok to return the aircraft to home base. As a precaution I took off; climbed and stayed in the vicinity of the airport to check all was ok. After about 5 minutes with everything apparently looking normal; the alternator circuit breaker popped again. I decided to return to the airport. Since we had the engine problem before I decided to declare an emergency on the unicom frequency to get priority for landing. The engine ran fine through landing; taxi until normal shutdown.

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Original NASA ASRS Text

Title: Long EZ pilot reports electrical failure and diverts to a nearby airport. During descent the engine quits but is not required for landing. After landing the battery is charged and the engine runup with no anomalies noted. The reporter elects to depart and remain over the airport where the circuit breaker trips again but the engine continues to run.

Narrative: During my scan I noticed my volts reading approx 12 volts and a slight draw on the amps. I noted my alternator circuit breaker popped. I turned off the alternator switch; turned off the avionics switch; reset the circuit breaker; and turned the alternator switch back on. The volts read approx 13.5 and amps were very high at approx 28 amps. The circuit breaker tripped again and I started heading to the nearest airport. Shortly the engine rpms dropped from around 2;500 rpms to 1;700 rpms and shortly after that then engine quit. Since I was in gliding distance of the airport I did not attempt a restart. After landing and parking the airplane I called and left a message with the owner of the aircraft. In the meantime I tried to do some trouble shooting. In attempting to restart the engine; the battery was weak so I pulled the battery and I was able to find someone who could put it on a charger. Several hours later; after I was able to talk to the owner of the airplane; he arrived at the airport. We reinstalled the battery and the owner started the airplane. Everything seemed to check good. We ran it for awhile; volts and amps were well within normal range. The magnetos and electronic ignition systems tested OK. We decided it was OK to return the aircraft to home base. As a precaution I took off; climbed and stayed in the vicinity of the airport to check all was OK. After about 5 minutes with everything apparently looking normal; the alternator circuit breaker popped again. I decided to return to the airport. Since we had the engine problem before I decided to declare an emergency on the Unicom frequency to get priority for landing. The engine ran fine through landing; taxi until normal shutdown.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.