diff --git a/Energy_Pie/module.php b/Energy_Pie/module.php
index 2998e32..1133651 100644
--- a/Energy_Pie/module.php
+++ b/Energy_Pie/module.php
@@ -180,7 +180,11 @@ class Energy_Pie extends IPSModule
         if ($archiveID <= 0) {
             return 0.0;
         }
-        $values = @AC_GetLoggedValues($archiveID, $varId, max(0, $tStart - 86400), $tEnd, 0);
+        $tCalcEnd = min($tEnd, time());
+        if ($tCalcEnd <= $tStart) {
+            return 0.0;
+        }
+        $values = @AC_GetLoggedValues($archiveID, $varId, max(0, $tStart - 86400), $tCalcEnd, 0);
         if (empty($values)) {
             return 0.0;
         }
@@ -194,14 +198,31 @@ class Energy_Pie extends IPSModule
         $dbg['last']  = (float)$values[count($values) - 1]['Value'];
         $vStart = null;
         $vEnd   = null;
+        $prev   = null;
+        $sum    = 0.0;
         foreach ($values as $v) {
             $ts = (int)$v['TimeStamp'];
+            $val = (float)$v['Value'];
+
+            if ($ts <= $tStart) {
+                $vStart = $val;
+                $prev = $val;
+                continue;
+            }
+
+            if ($ts > $tCalcEnd) break;
+
             if ($ts >= $tStart && $ts < $tEnd) {
                 $dbg['inRange']++;
             }
-            if ($ts <= $tStart) $vStart = (float)$v['Value'];
-            if ($ts <= $tEnd)   $vEnd   = (float)$v['Value'];
-            if ($ts > $tEnd) break;
+
+            if ($prev !== null) {
+                $diff = $val - $prev;
+                $sum += ($diff >= 0) ? $diff : max($val, 0.0);
+            }
+
+            $prev = $val;
+            $vEnd = $val;
         }
         if ($dbg['inRange'] === 0) {
             return 0.0;
@@ -210,8 +231,7 @@ class Energy_Pie extends IPSModule
         if ($vEnd === null)   $vEnd   = $dbg['last'];
         $dbg['vStart'] = $vStart;
         $dbg['vEnd']   = $vEnd;
-        $diff = $vEnd - $vStart;
-        return ($diff < 0) ? 0.0 : (float)$diff;
+        return $sum;
     }
     private function getLastLogTimestamp(int $varId): int
     {