diff --git a/.scripts/wm/battery.sh b/.scripts/wm/battery.sh
index c648eb3..0b6b4eb 100755
--- a/.scripts/wm/battery.sh
+++ b/.scripts/wm/battery.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-BAT_NUMBER=${BLOCK_INSTANCE:-"0"}
+BAT_NUMBER=${BLOCK_INSTANCE:-"$(acpi -b | grep ': [^Unknown]' | awk '{ print int($2) }')"}
 BAT_INFO="$(acpi -b | grep Battery\ $BAT_NUMBER:)"
 
 CAPACITY=$(echo $BAT_INFO | awk '{ print int($4) }')