diff --git a/src/Display_Graphic.cpp b/src/Display_Graphic.cpp
index 3975193..94a0de8 100644
--- a/src/Display_Graphic.cpp
+++ b/src/Display_Graphic.cpp
@@ -164,7 +164,7 @@ void DisplayGraphicClass::loop()
             uint8_t screenSaverOffsetX = enableScreensaver ? (_mExtra % 7) : 0;
             _diagram.redraw(screenSaverOffsetX);
         }
-        float watts = Datastore.getTotalAcPowerEnabled();
+        const float watts = Datastore.getTotalAcPowerEnabled();
         if (watts > 999) {
             snprintf(_fmtText, sizeof(_fmtText), i18n_current_power_kw[_display_language], watts / 1000);
         } else {
diff --git a/src/Display_Graphic_Diagram.cpp b/src/Display_Graphic_Diagram.cpp
index 7221086..e23c9d6 100644
--- a/src/Display_Graphic_Diagram.cpp
+++ b/src/Display_Graphic_Diagram.cpp
@@ -62,8 +62,8 @@ void DisplayGraphicDiagramClass::updatePeriod()
 
 void DisplayGraphicDiagramClass::redraw(uint8_t screenSaverOffsetX)
 {
-    uint8_t graphPosX = DIAG_POSX + ((screenSaverOffsetX > 3) ? 1 : 0); // screenSaverOffsetX expected to be in range 0..6
-    uint8_t graphPosY = DIAG_POSY;
+    const uint8_t graphPosX = DIAG_POSX + ((screenSaverOffsetX > 3) ? 1 : 0); // screenSaverOffsetX expected to be in range 0..6
+    const uint8_t graphPosY = DIAG_POSY;
 
     // draw diagram axis
     _display->drawVLine(graphPosX, graphPosY, CHART_HEIGHT);