diff --git a/Modules/energy/package/contents/ui/Graph.qml b/Modules/energy/package/contents/ui/Graph.qml
--- a/Modules/energy/package/contents/ui/Graph.qml
+++ b/Modules/energy/package/contents/ui/Graph.qml
@@ -66,7 +66,7 @@
 
     //take a QPointF
     function scalePoint(plot, currentUnixTime) {
-        var scaledX = (plot.x - (currentUnixTime / 1000 - xDuration)) / xDuration * plotWidth
+        var scaledX = (plot.x - (currentUnixTime / 1000 - xDuration)) / xDuration * plotWidth;
         var scaledY = (plot.y - yMin)  * plotHeight / (yMax - yMin);
 
         return Qt.point(xPadding + scaledX,
@@ -111,7 +111,7 @@
 
         var index = 0
 
-        while (data[index].x < (xMinUnixTime / 1000)) {
+        while ((index < data.length - 1) && (data[index].x < (xMinUnixTime / 1000))) {
             index++
         }
 
diff --git a/Modules/energy/package/contents/ui/main.qml b/Modules/energy/package/contents/ui/main.qml
--- a/Modules/energy/package/contents/ui/main.qml
+++ b/Modules/energy/package/contents/ui/main.qml
@@ -293,7 +293,10 @@
                 yMax: {
                     if (root.historyType == HistoryModel.RateType) {
                         // ceil to nearest 10
-                        return Math.floor(history.largestValue) + 10
+                        var max = Math.floor(history.largestValue)
+                        max = max - max % 10 + 10
+                        
+                        return max;
                     } else {
                         return 100;
                     }