C182 pilot reported a low voltage alert during cruise followed by the alternator going offline. While pilot was diverting the alternator came back online and flight landed safely.

Narrative

While enroute I was alerted by a tone; I scanned my instruments and noticed that my voltage indicators were flashing red; indicating 24.0 volts and amps were discharging. There was also a Low Voltage alert on the PFD. I first began to inspect the circuit breakers and found nothing had popped. I called ATC and said that I was having an electrical issue and was looking for an airport to divert to. We discussed ZZZ but the controller said that ZZZ1 was closer. I was given a heading to ZZZ1; turned that direction. The controller informed me that he was providing priority handling. It was suggested that I reduce the load on the electrical system; which I was in the process of doing. I retrieved the POH and looked at the Emergency Procedures; followed the instructions to reset the alternator but that was unsuccessful. With all lights off except for the beacon and with the #2 Avionic Bus shut down; I lost the transponder and that was discussed with the controller. Approximately 3-4 miles out from ZZZ1; I notice the alternator had come back online. I turned the #2 Avionics Bus on and completed the flight to landing at ZZZ1. Upon landing I called ATC on the phone per their request to report a successful and safe landing.I contacted my mechanic and discussed the situation. He had me perform a full runup which included loading the electrical system by turning on all electrical equipment. I performed this twice; from start up to shut down and there were no failures. The following day I resumed my trip with no further issues with the system. All indicators were normal.