diff --git a/apps/predbat/predbat.py b/apps/predbat/predbat.py
index 7314a731c..c09194842 100644
--- a/apps/predbat/predbat.py
+++ b/apps/predbat/predbat.py
@@ -393,7 +393,7 @@
     {"name": "calculate_fast_plan", "friendly_name": "Calculate plan faster (less accurate)", "type": "switch", "enable": "expert_mode", "default": False},
     {"name": "calculate_second_pass", "friendly_name": "Calculate full second pass (slower)", "type": "switch", "enable": "expert_mode", "default": False},
     {"name": "calculate_tweak_plan", "friendly_name": "Calculate tweak second pass", "type": "switch", "enable": "expert_mode", "default": False},
-    {"name": "calculate_regions", "friendly_name": "Calculate region optimisation", "type": "switch", "default": False},
+    {"name": "calculate_regions", "friendly_name": "Calculate region optimisation", "type": "switch", "enable": "expert_mode", "default": True},
     {"name": "calculate_inday_adjustment", "friendly_name": "Calculate in-day adjustment", "type": "switch", "enable": "expert_mode", "default": True},
     {
         "name": "calculate_plan_every",
diff --git a/docs/customisation.md b/docs/customisation.md
index b7ac69e0b..1c4b1ce79 100644
--- a/docs/customisation.md
+++ b/docs/customisation.md
@@ -179,6 +179,10 @@ charging sessions but will not reset it automatically.
 
 See the Predbat mode setting as above for basic calculation options
 
+**switch.predbat_calculate_regions** (_expert mode_) When True the a second pass of the initial thresholds is
+calculated in 4 hour regions before forming the detailed plan. Is True by default but can be turned off in expert
+mode.
+
 **switch.predbat_calculate_fast_plan** (_expert mode_) When True the plan is calculated with a limited number of
 windows to make calculations faster. When False (default) all windows are considered but planning will take a little
 longer but be more accurate.