On August 18, 2018, about 0946 central daylight time, a Cessna 210 airplane, N6958N, registered to a private individual, sustained substantial damage during a runway excursion at the Richard Lloyd Jones Jr. Airport (RVS), Tulsa, Oklahoma. The airline transport pilot, who was the sole occupant, was not injured. Visual meteorological conditions prevailed and an instrument flight rules (IFR) flight plan was filed for the flight. The personal flight was conducted under the provisions of Title 14 Federal Code of Regulations Part 91. The flight departed RVS about 0930 and was en route to the McAllen Miller International Airport (MFE), McAllen, Texas. According to the Federal Aviation Administration (FAA) inspector who responded to the accident, the pilot could not start the airplane due to a discharged battery, so he had the local fixed base operator (FBO) use a ground power starter to jump start the airplane. After takeoff, about 800 ft AGL, the pilot noticed that the radios became silent. He maneuvered the airplane upwind and started to troubleshoot the loss of radio communications (checked circuit breakers, recycled the avionics master switch, tried COMM 2, and tried the hand-held microphone mounted in the airplane). He switched his initial transponder code of 1730 to the emergency code 7600 on the transponder and set up to return to the airport to land on runway 11. The pilot tried to deploy the flaps and landing gear, but there was no indication that either extended. He checked to see if the landing gear extended by using the wing-mounted mirrors. During landing rollout, the pilot applied right rudder and brakes to try to stop the airplane safely. The airplane rolled off the runway into the grass with a collapsed left main landing gear. The FAA inspector examined the airplane and did not find any mechanical anomalies with the landing gear. He confirmed that the battery was completely discharged. Also, the airplane had been sitting on the ramp for about 3-4 months before the accident flight.