diff --git a/redfish/account_service/test_ipmi_redfish_user.robot b/redfish/account_service/test_ipmi_redfish_user.robot
index 55b2fe3..f26606b 100644
--- a/redfish/account_service/test_ipmi_redfish_user.robot
+++ b/redfish/account_service/test_ipmi_redfish_user.robot
@@ -17,7 +17,10 @@
 ${valid_password2}      0penBmc2
 ${admin_level_priv}     4
 ${operator_level_priv}  3
-${max_num_users}        ${15}
+# Refer:  #openbmc/phosphor-user-manager/blob/master/user_mgr.cpp
+# ipmiMaxUserNameLen = 16;    <-- IPMI
+# systemMaxUserNameLen = 30;  <-- Redfish account users
+${max_num_users}        ${30}
 ${empty_name_pattern}   ^User Name\\s.*\\s:\\s$
 
 ** Test Cases **