diff --git a/constants/battle_constants.php b/constants/battle_constants.php
index 5a85fef..3480de9 100644
--- a/constants/battle_constants.php
+++ b/constants/battle_constants.php
@@ -57,8 +57,17 @@
 
 /*** After-battle constants, default as Ogame ***/
 define('REPAIRED_DO_DEBRIS',true);
-define('SHIP_DEBRIS_FACTOR', 0.3); //Percentage of debris generated from destroyed defenses.
-define('DEFENSE_DEBRIS_FACTOR', 0.3); //Percentage of debris generated from destroyed ships.
+  
+//Percentage of debris generated from destroyed ships. 
+if (!defined('SHIP_DEBRIS_FACTOR')) {
+    define('SHIP_DEBRIS_FACTOR', 0.3);
+}
+
+//Percentage of debris generated from destroyed defenses.  
+if (!defined('DEFENSE_DEBRIS_FACTOR')) {
+    define('DEFENSE_DEBRIS_FACTOR', 0.3);
+}
+
 define('POINT_UNIT', 1000); //Ogame point = 1000 resources.
 define('MOON_UNIT_PROB', 100000);
 define('MAX_MOON_PROB', 20); //max probability to moon creation.