diff --git a/packages/helpermodules/measurement_logging/write_log.py b/packages/helpermodules/measurement_logging/write_log.py
index 77e35c50a6..59f3002eed 100644
--- a/packages/helpermodules/measurement_logging/write_log.py
+++ b/packages/helpermodules/measurement_logging/write_log.py
@@ -164,8 +164,18 @@ def save_log():
 
         entries = content["entries"]
         entries.append(new_entry)
-        content["names"] = get_names(content["entries"][-1], sh_log_data.sh_names)
-        content["colors"] = get_colors(content["entries"][-1])
+        existing_names = content.get("names")
+        if not isinstance(existing_names, dict):
+            existing_names = {}
+        new_names = get_names(content["entries"][-1], sh_log_data.sh_names)
+        existing_names.update(new_names)
+        content["names"] = existing_names
+        existing_colors = content.get("colors")
+        if not isinstance(existing_colors, dict):
+            existing_colors = {}
+        new_colors = get_colors(content["entries"][-1])
+        existing_colors.update(new_colors)
+        content["colors"] = existing_colors
         write_and_check(filepath, content)
         return content["entries"]
     except Exception:
@@ -384,7 +394,7 @@ def get_names(elements: Dict, sh_names: Dict, valid_names: Optional[Dict] = None
         Dictionary mit allen gültigen Namen, die in der Konfiguration hinterlegt sind.
         Ist None, wenn die Namen aus data ermittelt werden sollen.
     """
-    names = sh_names
+    names = dict(sh_names) if isinstance(sh_names, dict) else {}
     for group in elements.items():
         if group[0] not in ("bat", "consumer", "counter", "cp", "pv", "ev", "sh"):
             continue
diff --git a/packages/helpermodules/measurement_logging/write_log_test.py b/packages/helpermodules/measurement_logging/write_log_test.py
index 11421bc76b..1ff6302b4f 100644
--- a/packages/helpermodules/measurement_logging/write_log_test.py
+++ b/packages/helpermodules/measurement_logging/write_log_test.py
@@ -1,4 +1,5 @@
 from unittest.mock import Mock
+import json
 
 from helpermodules.measurement_logging import write_log
 from helpermodules.measurement_logging.write_log import get_names
@@ -121,3 +122,42 @@ def test_fix_values_missing_components():
                             'pv': {'all': {'exported': 3269}, 'pv1': {'exported': 0}},
                             'sh': {},
                             'timestamp': 1709109001}
+
+
+def test_save_log_keeps_existing_names_and_colors_when_writing_new_entry(monkeypatch):
+    # setup
+    existing_content = {
+        "entries": [{"timestamp": 1, "cp": {"cp1": {"imported": 1, "exported": 0}}}],
+        "names": {"cp1": "Bestehender Ladepunkt"},
+        "colors": {"cp1": "#111111"},
+    }
+    mocked_file = Mock()
+    mocked_file.__enter__ = Mock(return_value=mocked_file)
+    mocked_file.__exit__ = Mock(return_value=None)
+    mocked_file.read = Mock(return_value=json.dumps(existing_content))
+    monkeypatch.setattr("builtins.open", Mock(return_value=mocked_file))
+    monkeypatch.setattr(write_log.timecheck, "create_timestamp_YYYYMMDD", Mock(return_value="20261002"))
+    monkeypatch.setattr(write_log, "get_previous_entry", Mock(return_value=existing_content["entries"][-1]))
+    monkeypatch.setattr(write_log, "LegacySmartHomeLogData", Mock(return_value=Mock(sh_names={}, sh_dict={})))
+
+    new_entry = {"timestamp": 2, "cp": {"cp2": {"imported": 2, "exported": 0}}}
+    monkeypatch.setattr(write_log, "create_entry", Mock(return_value=new_entry))
+    monkeypatch.setattr(write_log, "get_names", Mock(
+        return_value={"cp1": "Bestehender Ladepunkt", "cp2": "Neuer Ladepunkt"}))
+    monkeypatch.setattr(write_log, "get_colors", Mock(return_value={"cp1": "#111111", "cp2": "#222222"}))
+    write_and_check_mock = Mock()
+    monkeypatch.setattr(write_log, "write_and_check", write_and_check_mock)
+
+    # execution
+    write_log.save_log()
+
+    # evaluation
+    written_content = write_and_check_mock.call_args.args[1]
+    assert written_content["names"] == {
+        "cp1": "Bestehender Ladepunkt",
+        "cp2": "Neuer Ladepunkt",
+    }
+    assert written_content["colors"] == {
+        "cp1": "#111111",
+        "cp2": "#222222",
+    }