diff --git a/lib/Hoymiles/src/commands/CommandAbstract.h b/lib/Hoymiles/src/commands/CommandAbstract.h
index 8029ac8..e6abc68 100644
--- a/lib/Hoymiles/src/commands/CommandAbstract.h
+++ b/lib/Hoymiles/src/commands/CommandAbstract.h
@@ -57,5 +57,5 @@ protected:
     uint64_t _routerAddress;
 
 private:
-    void convertSerialToPacketId(uint8_t buffer[], uint64_t serial);
+    static void convertSerialToPacketId(uint8_t buffer[], uint64_t serial);
 };
\ No newline at end of file