Narrative:

While in cruise at 9000 ft MSL, en route to kfxe, on assigned heading of 100 degrees, aircraft experienced total loss of electrical power. Continued on assigned heading and initiated visual descent in anticipation of landing. Set 7700 in transponder and attempted to identify and correct problem which caused loss of power. After approximately 20 mins, when the landing gear circuit breaker was pulled to facilitate extension of the landing gear, power was restored and communication with ZMA was restored. Aircraft landed at ksua without incident. It was determined that the battery failed in-flight. The battery light did not illuminate. The ammeter showed a slight discharge. A local FBO replaced the battery and troubleshot the aircraft's electrical system. It was suspected that the landing gear power pack was re-cycling and may have caused the power loss.

Google
 

Original NASA ASRS Text

Title: A C-210 PLT EXPERIENCED A TOTAL LOSS OF ELECTRICAL PWR, CAUSING A DIVERSION TO SUA FOR A SAFE LNDG.

Narrative: WHILE IN CRUISE AT 9000 FT MSL, ENRTE TO KFXE, ON ASSIGNED HDG OF 100 DEGS, ACFT EXPERIENCED TOTAL LOSS OF ELECTRICAL PWR. CONTINUED ON ASSIGNED HDG AND INITIATED VISUAL DSCNT IN ANTICIPATION OF LNDG. SET 7700 IN XPONDER AND ATTEMPTED TO IDENT AND CORRECT PROB WHICH CAUSED LOSS OF PWR. AFTER APPROX 20 MINS, WHEN THE LNDG GEAR CIRCUIT BREAKER WAS PULLED TO FACILITATE EXTENSION OF THE LNDG GEAR, PWR WAS RESTORED AND COM WITH ZMA WAS RESTORED. ACFT LANDED AT KSUA WITHOUT INCIDENT. IT WAS DETERMINED THAT THE BATTERY FAILED INFLT. THE BATTERY LIGHT DID NOT ILLUMINATE. THE AMMETER SHOWED A SLIGHT DISCHARGE. A LCL FBO REPLACED THE BATTERY AND TROUBLESHOT THE ACFT'S ELECTRICAL SYS. IT WAS SUSPECTED THAT THE LNDG GEAR PWR PACK WAS RE-CYCLING AND MAY HAVE CAUSED THE PWR LOSS.

Data retrieved from NASA's ASRS site as of July 2007 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.