diff --git a/main.py b/main.py
index d4cebf5..012ffdc 100644
--- a/main.py
+++ b/main.py
@@ -46,41 +46,66 @@ def main():
     with serial.Serial(device_name, 115200, timeout=1) as ser:
         shutdown_triggered = False
         inverter_online = True
-        while running:
-            line = ser.readline().decode(errors="ignore").strip()
-            if line == "":
-                logger.warning("No serial data")
-                continue
-            elif line == "0":
-                logger.debug("Inverter Online")
-                inverter_online = True
-            elif not inverter_online:
-                if time.time() - last_online > shutdown_timer:
-                    shutdown_triggered = True
-                    break
-            else:
-                if inverter_online:
-                    inverter_online = False
-                    last_online = time.time()
-                    logger.info(f"Running on UPS reserve, offline for {time.time()-last_online}s")
+        last_online = time.monotonic()
+        receiving_data = True
+        last_logged = -1
+        try:
+            while running:
+                line = ser.readline().decode(errors="ignore").strip()
 
-        if shutdown_triggered:
-            logger.info(f"Inverter offline for {shutdown_timer} seconds")
-            try:
-                requests.post(
-                    "https://ntfy.fieryeagle.org/Internet-Alerts",
-                    data="Inverter offline, shutting down".encode("utf-8"),
-                    headers={
-                        "Title": "Hydrogen running on reserve power",
-                        "Authorization": f"Bearer {ntfy_token}"
-                    },
-                    timeout=5
-                )
-            except Exception as e:
-                logger.error(f"Failed to send notification: {e}")
-            os.system("shutdown now")
-        else:
-            logger.info("Exited cleanly (service stop)")
+                if line != "" and not receiving_data:
+                    receiving_data = True
+                    logger.info("Serial data restored")
+
+                if line == "0":
+                    if not inverter_online:
+                        logger.info("Inverter restored")
+                    inverter_online = True
+                    last_online = time.monotonic()
+
+                elif line == "1":
+                    if inverter_online:
+                        inverter_online = False
+                        logger.info("Running on UPS reserve")
+
+                elif line == "":
+                    if receiving_data:
+                        receiving_data = False
+                        logger.warning("No serial data")
+
+                else:
+                    logger.warning(f"Unexpected serial data: {line}")
+
+                if not inverter_online:
+                    sec = int(time.monotonic() - last_online)
+
+                    if sec % 10 == 0 and sec != last_logged:
+                        logger.info(f"Offline for {sec}s")
+                        last_logged = sec
+
+                    if sec >= shutdown_timer:
+                        shutdown_triggered = True
+                        break
+            if shutdown_triggered:
+                logger.info(f"Inverter offline for {shutdown_timer} seconds")
+                try:
+                    requests.post(
+                        "https://ntfy.fieryeagle.org/Internet-Alerts",
+                        data="Inverter offline, shutting down".encode("utf-8"),
+                        headers={
+                            "Title": "Hydrogen running on reserve power",
+                            "Authorization": f"Bearer {ntfy_token}"
+                        },
+                        timeout=5
+                    )
+                except Exception as e:
+                    logger.error(f"Failed to send notification: {e}")
+                os.system("shutdown now")
+            else:
+                logger.info("Exited cleanly (service stop)")
+        except serial.SerialException as e:
+            logger.error(f"Serial device error: {e}")
+            raise
 
 if __name__ == "__main__":
     main()
\ No newline at end of file