On August 9, 2018, about 1312 eastern daylight time, a Cessna R182, N1693R, was substantially damaged when its main landing gear collapsed during the landing roll at the Florence Regional Airport (FLO), Florence, South Carolina. The private pilot was not injured. The airplane was owned and operated by a flying club, under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight that originated about 20 minutes earlier from a private airstrip near Andrews, South Carolina.The pilot stated that before departure, he performed a preflight inspection of the airplane using a copy of the checklist from the airplane's Pilot's Operating Handbook (POH). After the completion of the inspection he attempted to start the engine but could not because the battery was dead. A portable electrical power supply was required to start the engine. After the engine was started, he checked all gauges and reported normal indications, including the alternator, which was working. The ammeter indicated zero or a "hair to the right of zero" after the engine was started. Prior to departure he did not have a mechanic troubleshoot the reason for the dead battery. The pilot further stated that after takeoff, he proceeded towards FLO, and about 10 minutes into the flight while flying at 2,500 feet mean sea level, and in communication with Florence Approach Control, he noted the fuel gauges were indicating zero and the ammeter was showing a discharge, or 3/16 to the left of zero. He did not consult, nor did he perform any emergency procedures from the POH pertaining to electrical system fault. He continued to FLO, lowered the landing gear by selecting the landing gear lever to the "GEAR DOWN" position and was cleared to land. Though he visually observed that the nose landing gear was extended, there was no indication from the single light on the instrument panel that all landing gears were down and locked. The pilot raised the landing gear selector handle then lowered it again, but again there was no landing gear down indication from the single light. He performed a flyby of the FLO air traffic control tower and was advised that the landing gear appeared to be down. He entered the downwind leg of the airport traffic pattern for runway 27 which he extended due to an inbound airplane, and at that time the tower controller asked him his intentions, but he was unable to reply because the airplane had lost all electrical power. He turned onto the base and final legs of the airport traffic pattern for runway 27, and performed a shallow approach, touching down first on the main landing gear. During the landing roll about 500 to 1,000 feet down the runway, the main landing gear collapsed, the airplane began to veer to the left, and the left wing and horizontal stabilizer contacted the runway. The airplane came to rest in the grass off the left side of the runway near the intersection of runway 09/27 and 01/19. According to personnel involved in recovery of the airplane, inspection of the cockpit prior to recovery revealed the landing gear selector was in the down position and the emergency extension handle was not extended. The airplane was raised from the runway and the right main landing gear was extended and locked by hand, while the left main landing gear was hand pumped into the down and locked position. Prior to lowering, the airplane's battery was turned on and there was insufficient voltage to power the airplane's electrical system. The airplane was then towed to the ramp. Examination of the airplane was performed following recovery by a Federal Aviation Administration inspector. The examination revealed the battery voltage was 11V. The battery was then charged. The airplane was placed on jacks and jacked up, and with the battery connected it was indicating 24.11V. The master switch was turned on, and the gear green down and lock light was illuminated. The landing gear system was first exercised by electrically cycling the gear up, down, then up again. The aural horn was heard during the transition and functioned normally, and the amber gear up and lock light was illuminated when the gear was in the up position. Using the emergency procedures checklist found in the POH, under the emergency procedures section 3, paragraph 3.8, the master switch was turned off to simulate an electrical failure. The gear handle was put into the down position, the landing gear then fell with the force of gravity and were hand pumped into the down and locked position using the emergency hand pump. The master switch was then turned back on and the gear down and lock light was verified as being illuminated. The airplane was then removed from the jacks. No determination was made as to the reason for the electrical failure. According to the Pilot's Operating Handbook, the procedures to perform when the ammeter shows discharge include: 1. Alternator -- OFF 2. Nonessential Radio/Electrical Equipment – OFF 3. Flight –TERMINATE as soon as practical