diff --git a/homeassistant/components/apsystems/coordinator.py b/homeassistant/components/apsystems/coordinator.py
index 96956bafc3e..6ba4f01dbc8 100644
--- a/homeassistant/components/apsystems/coordinator.py
+++ b/homeassistant/components/apsystems/coordinator.py
@@ -8,7 +8,7 @@ from datetime import timedelta
 from APsystemsEZ1 import APsystemsEZ1M, ReturnAlarmInfo, ReturnOutputData
 
 from homeassistant.core import HomeAssistant
-from homeassistant.helpers.update_coordinator import DataUpdateCoordinator
+from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
 
 from .const import LOGGER
 
@@ -34,6 +34,13 @@ class ApSystemsDataCoordinator(DataUpdateCoordinator[ApSystemsSensorData]):
         )
         self.api = api
 
+    async def _async_setup(self) -> None:
+        try:
+            max_power = (await self.api.get_device_info()).maxPower
+        except (ConnectionError, TimeoutError):
+            raise UpdateFailed from None
+        self.api.max_power = max_power
+
     async def _async_update_data(self) -> ApSystemsSensorData:
         output_data = await self.api.get_output_data()
         alarm_info = await self.api.get_alarm_info()
diff --git a/homeassistant/components/apsystems/number.py b/homeassistant/components/apsystems/number.py
index f9b535d7d6a..51e7130587f 100644
--- a/homeassistant/components/apsystems/number.py
+++ b/homeassistant/components/apsystems/number.py
@@ -26,7 +26,6 @@ async def async_setup_entry(
 class ApSystemsMaxOutputNumber(ApSystemsEntity, NumberEntity):
     """Base sensor to be used with description."""
 
-    _attr_native_max_value = 800
     _attr_native_min_value = 30
     _attr_native_step = 1
     _attr_device_class = NumberDeviceClass.POWER
@@ -42,6 +41,7 @@ class ApSystemsMaxOutputNumber(ApSystemsEntity, NumberEntity):
         super().__init__(data)
         self._api = data.coordinator.api
         self._attr_unique_id = f"{data.device_id}_output_limit"
+        self._attr_native_max_value = data.coordinator.api.max_power
 
     async def async_update(self) -> None:
         """Set the state with the value fetched from the inverter."""