diff --git a/pypowerwall/cloud.py b/pypowerwall/cloud.py
index a14a9bb..f5c4248 100644
--- a/pypowerwall/cloud.py
+++ b/pypowerwall/cloud.py
@@ -388,7 +388,7 @@ def poll(self, api):
 
         elif api == '/vitals':
             # TODO: Assemble vitals data payload
-            data = None
+            data = {}
 
         elif api in ['/api/system_status/soe']:
             battery = self.get_battery()