diff --git a/custom_components/battery_notes/diagnostics.py b/custom_components/battery_notes/diagnostics.py
index 7ff66e6c2..67e659c96 100644
--- a/custom_components/battery_notes/diagnostics.py
+++ b/custom_components/battery_notes/diagnostics.py
@@ -1,12 +1,48 @@
 """Diagnostic helpers."""
 
+from __future__ import annotations
+
+from typing import Any
+
 from homeassistant.config_entries import ConfigEntry
+from homeassistant.const import CONF_DEVICE_ID
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers import (
+    device_registry as dr,
+)
+from homeassistant.helpers import (
+    entity_registry as er,
+)
+
+from .common import get_device_model_id
+from .const import CONF_SOURCE_ENTITY_ID
 
 
 async def async_get_config_entry_diagnostics(
-    entry: ConfigEntry,
-) -> dict:
+    hass: HomeAssistant, config_entry: ConfigEntry
+) -> dict[str, Any]:
     """Return diagnostics for a config entry."""
-    return {
-        "entry": entry.as_dict(),
-    }
+
+    device_id = config_entry.data.get(CONF_DEVICE_ID, None)
+    source_entity_id = config_entry.data.get(CONF_SOURCE_ENTITY_ID, None)
+
+    device_registry = dr.async_get(hass)
+    entity_registry = er.async_get(hass)
+
+    if source_entity_id:
+        entity = entity_registry.async_get(source_entity_id)
+        device_id = entity.device_id
+
+    device_entry = device_registry.async_get(device_id)
+
+    diagnostics = {"entry": config_entry.as_dict()}
+    if device_entry:
+        device_info = {
+            "manufacturer": device_entry.manufacturer,
+            "model": device_entry.model,
+            "model_id": get_device_model_id(device_entry),
+            "hw_version": device_entry.hw_version,
+        }
+        diagnostics.update({"device": device_info})
+
+    return diagnostics