diff --git a/homeassistant/components/tesla_fleet/coordinator.py b/homeassistant/components/tesla_fleet/coordinator.py
index 20d2d70b5dc..e3a31a2c0dc 100644
--- a/homeassistant/components/tesla_fleet/coordinator.py
+++ b/homeassistant/components/tesla_fleet/coordinator.py
@@ -247,11 +247,15 @@ class TeslaFleetEnergySiteHistoryCoordinator(DataUpdateCoordinator[dict[str, Any
             raise UpdateFailed(e.message) from e
         self.updated_once = True
 
+        if not data or not isinstance(data.get("time_series"), list):
+            raise UpdateFailed("Received invalid data")
+
         # Add all time periods together
         output = dict.fromkeys(ENERGY_HISTORY_FIELDS, 0)
         for period in data.get("time_series", []):
             for key in ENERGY_HISTORY_FIELDS:
-                output[key] += period.get(key, 0)
+                if key in period:
+                    output[key] += period[key]
 
         return output