diff --git a/src/akkudoktoreosserver/flask_server.py b/src/akkudoktoreosserver/flask_server.py
index a9bcf84..7062a0e 100755
--- a/src/akkudoktoreosserver/flask_server.py
+++ b/src/akkudoktoreosserver/flask_server.py
@@ -243,7 +243,7 @@ def flask_optimize():
 
         # Optional min SoC PV Battery
         if "min_soc_prozent" not in parameter:
-            parameter["min_soc_prozent"] = None
+            parameter["min_soc_prozent"] = 0
 
         # Perform optimization simulation
         result = opt_class.optimierung_ems(parameter=parameter, start_hour=datetime.now().hour)