Event ID 521 — Active battery count change.

{
  "system": {
    "provider": "Microsoft-Windows-Kernel-Power",
    "guid": "331C3B3A-2005-44C2-AC5E-77220C37D6B4",
    "event_source_name": "",
    "event_id": 521,
    "version": 0,
    "level": 4,
    "task": 220,
    "opcode": 0,
    "keywords": 9223372036854776836,
    "time_created": "2022-04-04T13:11:11.019552+00:00",
    "event_record_id": 1541,
    "correlation": {},
    "execution": {
      "process_id": 4,
      "thread_id": 260
    },
    "channel": "System",
    "computer": "WIN-TKC15D7KHUR",
    "security": {
      "user_id": "S-1-5-18"
    }
  },
  "event_data": {
    "ValidBatteryCount": 1,
    "ErrorBatteryCount": 0,
    "AbandonedBatteryCount": 0
  },
  "message": ""
}