diff --git a/main/battery.cpp b/main/battery.cpp
index 3de7a8b..df1f24f 100644
--- a/main/battery.cpp
+++ b/main/battery.cpp
@@ -197,4 +197,5 @@ std::string getBatteryDebugString()
 
 namespace battery {
 std::optional<float> bootBatPercentage;
+std::optional<float> bootBatWh;
 }
diff --git a/main/battery.h b/main/battery.h
index e17ff06..466a97f 100644
--- a/main/battery.h
+++ b/main/battery.h
@@ -35,4 +35,5 @@ float getTarget_mAh();
 
 namespace battery {
 extern std::optional<float> bootBatPercentage;
+extern std::optional<float> bootBatWh;
 }