diff --git a/homeassistant/components/nut/__init__.py b/homeassistant/components/nut/__init__.py
index 45c5474f27e..b98522feb4e 100644
--- a/homeassistant/components/nut/__init__.py
+++ b/homeassistant/components/nut/__init__.py
@@ -134,7 +134,7 @@ def _firmware_from_status(status):
 def _serial_from_status(status):
     """Find the best serialvalue from the status."""
     serial = status.get("device.serial") or status.get("ups.serial")
-    if serial and serial == "unknown":
+    if serial and (serial.lower() == "unknown" or serial.count("0") == len(serial)):
         return None
     return serial
 
diff --git a/tests/components/nut/test_sensor.py b/tests/components/nut/test_sensor.py
index a04f570d367..430720785ca 100644
--- a/tests/components/nut/test_sensor.py
+++ b/tests/components/nut/test_sensor.py
@@ -9,6 +9,10 @@ async def test_pr3000rt2u(hass):
     """Test creation of PR3000RT2U sensors."""
 
     await async_init_integration(hass, "PR3000RT2U", ["battery.charge"])
+    registry = await hass.helpers.entity_registry.async_get_registry()
+    entry = registry.async_get("sensor.ups1_battery_charge")
+    assert entry
+    assert entry.unique_id == "CPS_PR3000RT2U_PYVJO2000034_battery.charge"
 
     state = hass.states.get("sensor.ups1_battery_charge")
     assert state.state == "100"
@@ -30,6 +34,10 @@ async def test_cp1350c(hass):
     """Test creation of CP1350C sensors."""
 
     await async_init_integration(hass, "CP1350C", ["battery.charge"])
+    registry = await hass.helpers.entity_registry.async_get_registry()
+    entry = registry.async_get("sensor.ups1_battery_charge")
+    # No unique id, no registry entry
+    assert not entry
 
     state = hass.states.get("sensor.ups1_battery_charge")
     assert state.state == "100"
@@ -51,6 +59,64 @@ async def test_5e850i(hass):
     """Test creation of 5E850I sensors."""
 
     await async_init_integration(hass, "5E850I", ["battery.charge"])
+    registry = await hass.helpers.entity_registry.async_get_registry()
+    entry = registry.async_get("sensor.ups1_battery_charge")
+    # No unique id, no registry entry
+    assert not entry
+
+    state = hass.states.get("sensor.ups1_battery_charge")
+    assert state.state == "100"
+
+    expected_attributes = {
+        "device_class": "battery",
+        "friendly_name": "Ups1 Battery Charge",
+        "state": "Online",
+        "unit_of_measurement": "%",
+    }
+    # Only test for a subset of attributes in case
+    # HA changes the implementation and a new one appears
+    assert all(
+        state.attributes[key] == expected_attributes[key] for key in expected_attributes
+    )
+
+
+async def test_backupsses600m1(hass):
+    """Test creation of BACKUPSES600M1 sensors."""
+
+    await async_init_integration(hass, "BACKUPSES600M1", ["battery.charge"])
+    registry = await hass.helpers.entity_registry.async_get_registry()
+    entry = registry.async_get("sensor.ups1_battery_charge")
+    # No unique id, no registry entry
+    assert entry
+    assert (
+        entry.unique_id
+        == "American Power Conversion_Back-UPS ES 600M1_4B1713P32195 _battery.charge"
+    )
+
+    state = hass.states.get("sensor.ups1_battery_charge")
+    assert state.state == "100"
+
+    expected_attributes = {
+        "device_class": "battery",
+        "friendly_name": "Ups1 Battery Charge",
+        "state": "Online",
+        "unit_of_measurement": "%",
+    }
+    # Only test for a subset of attributes in case
+    # HA changes the implementation and a new one appears
+    assert all(
+        state.attributes[key] == expected_attributes[key] for key in expected_attributes
+    )
+
+
+async def test_cp1500pfclcd(hass):
+    """Test creation of CP1500PFCLCD sensors."""
+
+    await async_init_integration(hass, "CP1500PFCLCD", ["battery.charge"])
+    registry = await hass.helpers.entity_registry.async_get_registry()
+    entry = registry.async_get("sensor.ups1_battery_charge")
+    # No unique id, no registry entry
+    assert not entry
 
     state = hass.states.get("sensor.ups1_battery_charge")
     assert state.state == "100"
diff --git a/tests/components/nut/util.py b/tests/components/nut/util.py
index 5bd29042ea8..788076a7c9f 100644
--- a/tests/components/nut/util.py
+++ b/tests/components/nut/util.py
@@ -26,10 +26,6 @@ async def async_init_integration(
     ups_fixture = f"nut/{ups_fixture}.json"
     list_vars = json.loads(load_fixture(ups_fixture))
 
-    import pprint
-
-    pprint.pprint(list_vars)
-
     mock_pynut = _get_mock_pynutclient(list_ups={"ups1": "UPS 1"}, list_vars=list_vars)
 
     with patch(
diff --git a/tests/fixtures/nut/BACKUPSES600M1.json b/tests/fixtures/nut/BACKUPSES600M1.json
new file mode 100644
index 00000000000..1acd0ef0444
--- /dev/null
+++ b/tests/fixtures/nut/BACKUPSES600M1.json
@@ -0,0 +1,47 @@
+{
+   "ups.realpower.nominal" : "330",
+   "input.voltage" : "123.0",
+   "ups.mfr" : "American Power Conversion",
+   "driver.version" : "2.7.4",
+   "ups.test.result" : "No test initiated",
+   "input.voltage.nominal" : "120",
+   "input.transfer.low" : "92",
+   "driver.parameter.pollinterval" : "15",
+   "driver.version.data" : "APC HID 0.96",
+   "driver.parameter.pollfreq" : "30",
+   "battery.mfr.date" : "2017/04/01",
+   "ups.beeper.status" : "enabled",
+   "battery.date" : "2001/09/25",
+   "driver.name" : "usbhid-ups",
+   "battery.charge" : "100",
+   "ups.status" : "OL",
+   "ups.model" : "Back-UPS ES 600M1",
+   "battery.runtime.low" : "120",
+   "ups.firmware" : "928.a5 .D",
+   "ups.delay.shutdown" : "20",
+   "device.model" : "Back-UPS ES 600M1",
+   "device.serial" : "4B1713P32195 ",
+   "input.sensitivity" : "medium",
+   "ups.firmware.aux" : "a5 ",
+   "input.transfer.reason" : "input voltage out of range",
+   "ups.timer.reboot" : "0",
+   "battery.voltage.nominal" : "12.0",
+   "ups.vendorid" : "051d",
+   "input.transfer.high" : "139",
+   "battery.voltage" : "13.7",
+   "battery.charge.low" : "10",
+   "battery.type" : "PbAc",
+   "ups.mfr.date" : "2017/04/01",
+   "ups.timer.shutdown" : "-1",
+   "device.mfr" : "American Power Conversion",
+   "driver.parameter.port" : "auto",
+   "battery.charge.warning" : "50",
+   "device.type" : "ups",
+   "driver.parameter.vendorid" : "051d",
+   "ups.serial" : "4B1713P32195 ",
+   "ups.load" : "22",
+   "driver.version.internal" : "0.41",
+   "battery.runtime" : "1968",
+   "driver.parameter.synchronous" : "no",
+   "ups.productid" : "0002"
+}
diff --git a/tests/fixtures/nut/CP1500PFCLCD.json b/tests/fixtures/nut/CP1500PFCLCD.json
new file mode 100644
index 00000000000..8f12ae96df6
--- /dev/null
+++ b/tests/fixtures/nut/CP1500PFCLCD.json
@@ -0,0 +1,43 @@
+{
+   "battery.runtime.low" : "300",
+   "driver.parameter.port" : "auto",
+   "ups.delay.shutdown" : "20",
+   "driver.parameter.pollfreq" : "30",
+   "ups.beeper.status" : "disabled",
+   "input.voltage.nominal" : "120",
+   "device.serial" : "000000000000",
+   "ups.timer.shutdown" : "-60",
+   "input.voltage" : "122.0",
+   "ups.status" : "OL",
+   "ups.model" : "CP1500PFCLCD",
+   "device.mfr" : "CPS",
+   "device.model" : "CP1500PFCLCD",
+   "input.transfer.low" : "88",
+   "battery.mfr.date" : "CPS",
+   "driver.version" : "2.7.4",
+   "driver.version.data" : "CyberPower HID 0.4",
+   "driver.parameter.synchronous" : "no",
+   "ups.realpower.nominal" : "900",
+   "ups.productid" : "0501",
+   "ups.mfr" : "CPS",
+   "ups.vendorid" : "0764",
+   "driver.version.internal" : "0.41",
+   "output.voltage" : "138.0",
+   "battery.runtime" : "10530",
+   "device.type" : "ups",
+   "battery.charge.low" : "10",
+   "ups.timer.start" : "-60",
+   "driver.parameter.pollinterval" : "15",
+   "ups.load" : "0",
+   "ups.serial" : "000000000000",
+   "input.transfer.high" : "139",
+   "battery.charge.warning" : "20",
+   "battery.voltage.nominal" : "24",
+   "driver.parameter.vendorid" : "0764",
+   "driver.name" : "usbhid-ups",
+   "battery.type" : "PbAcid",
+   "ups.delay.start" : "30",
+   "battery.voltage" : "24.0",
+   "battery.charge" : "100",
+   "ups.test.result" : "No test initiated"
+}