diff --git a/powerwall.sh b/powerwall.sh
index 570de817..b9fa057b 100755
--- a/powerwall.sh
+++ b/powerwall.sh
@@ -14,14 +14,15 @@ VERBOSE=false
 
 
 CHECKTEMP(){
+	cw=20;
 	if [ "${1}" != "" ]; then
 		reading=$(CHECKTEMPSENSOR ${1})
-		c=0; cw=30; spc=''; spc1=${cw}-${#1}; until [ $c = ${spc1} ]; do spc="${spc} "; c=`expr $c + 1`; done
+		c=0; spc=''; spc1=`expr ${cw} - ${#1}`; until [ $c = ${spc1} ]; do spc="${spc} "; c=`expr $c + 1`; done
 		echo "${1}${spc}: ${reading}"
 	else
 		for SENSOR in ${!SENSOR_ID[@]}; do
 			reading=$(CHECKTEMPSENSOR ${SENSOR})
-			c=0; cw=20; spc=''; spc1=`expr ${cw} - ${#SENSOR}`; until [ $c = ${spc1} ]; do spc="${spc} "; c=`expr $c + 1`; done
+			c=0; spc=''; spc1=`expr ${cw} - ${#SENSOR}`; until [ $c = ${spc1} ]; do spc="${spc} "; c=`expr $c + 1`; done
 			echo "${SENSOR}${spc}: ${reading}"
 		done
 	fi