On August 28, 1997, at 2130 hours mountain standard time, a Cessna T210J, N2280R, collided with a ditch after landing at Avra Valley Airport, Tucson, Arizona. The aircraft sustained substantial damage, and the private pilot was not injured. The aircraft was operated by the pilot as a personal flight under 14 CFR Part 91 when the accident occurred. The flight originated in Sierra Vista, Arizona, at 2100. Visual meteorological conditions prevailed at the time. The pilot reported that the aircraft sustained a complete electrical system failure while en route to La Cholla Airpark, his intended destination. He was unable to activate the airport lighting or use the aircraft taxi/landing lights. He decided to land at Avra Valley Airport which had a lighted runway. Following the landing on runway 30, he turned off the runway on what he believed was a taxiway that led to the terminal. The attached airport diagram annotates the taxiway in question as taxiway "B". The pilot claimed that the floodlights on top of the "T" hangers were in his eyes and he could not see where he was going. Shortly after he turned toward the area he thought was the ramp/terminal area, the aircraft encountered the drainage ditch. The pilot told the FAA Airworthiness Inspector that he was unfamiliar with the airport layout. The Safety Board examined the drainage ditch and adjoining taxiway and determined that the aircraft was traveling in a direction opposite the path that would have taken it to the ramp area when the accident occurred. Additionally, skid marks were left on the taxiway at a point just before the tire left the paved area. The taxiway does not have any lights. A postaccident examination of the electrical system did not identify the source of the electrical problem. The alternator and voltage regulator were tested satisfactorily. The wiring system was tested, with no faults located. The only discrepancy noted was that one cell of the battery only charged to 50 percent of the load. The pilot told the Safety Board that the aircraft departed the taxiway about 20 feet from the intersection of the two taxiways. The airport manager said he was going to take steps to redirect the floodlight's beam to light the terminal area in a way that would be less conducive to restricting night vision. The Safety Board examined the Southwest U.S. Airport/Facility Directory to see if there was any mention of the drainage ditch in the remarks section listed under Avra Valley Airport. The Safety Board was unable to locate any descriptive data concerning the ditch from the NOTAM files when Prescott FSS was contacted.