commander: Add missing parameter definition

src/modules/commander/commander_params.c

@@ -67,6 +67,16 @@ PARAM_DEFINE_FLOAT(BAT_V_EMPTY, 3.4f);
  */
 PARAM_DEFINE_FLOAT(BAT_V_CHARGED, 4.2f);
 
+/**
+ * Voltage drop per cell on 100% load
+ *
+ * This implicitely defines the internal resistance
+ * to maximum current ratio and assumes linearity.
+ *
+ * @group Battery Calibration
+ */
+PARAM_DEFINE_FLOAT(BAT_V_LOAD_DROP, 0.06f);
+
 /**
  * Number of cells.
  *