diff --git a/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java b/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java
index c5b90bbb..bab3c046 100644
--- a/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java
+++ b/mpmaster/src/main/java/com/xypower/mpmaster/MpMasterService.java
@@ -1060,7 +1060,7 @@ public class MpMasterService extends Service {
     public static String getBatteryVoltage() {
         int val = 0;
         for (int idx = 0; idx < 3; idx++) {
-            val = MpMasterService.getInt(115);
+            val = MpMasterService.getInt(117);
             if (val > 0) {
                 return Integer.toString(val / 1000) + "." + Integer.toString((val % 1000) / 100);
             }