diff --git a/btrfs-balance.sh b/btrfs-balance.sh
index 26013e0..689e6d5 100755
--- a/btrfs-balance.sh
+++ b/btrfs-balance.sh
@@ -15,7 +15,7 @@ if [ -f /etc/default/btrfsmaintenance ] ; then
 fi
 
 if [ "$BTRFS_BALANCE_WAIT_AC_POWER" = "true" ]; then
-	wait_ac_power $BTRFS_AC_POWER_TIMEOUT "$BTRFS_AC_POWER_DEVICE"
+	wait_ac_power $BTRFS_AC_POWER_TIMEOUT $BTRFS_AC_POWER_DEVICE
 fi
 
 LOGIDENTIFIER='btrfs-balance'
diff --git a/btrfs-defrag.sh b/btrfs-defrag.sh
index edf6b3b..68be48d 100755
--- a/btrfs-defrag.sh
+++ b/btrfs-defrag.sh
@@ -15,7 +15,7 @@ if [ -f /etc/default/btrfsmaintenance ] ; then
 fi
 
 if [ "$BTRFS_DEFRAG_WAIT_AC_POWER" = "true" ]; then
-	wait_ac_power $BTRFS_AC_POWER_TIMEOUT "$BTRFS_AC_POWER_DEVICE"
+	wait_ac_power $BTRFS_AC_POWER_TIMEOUT $BTRFS_AC_POWER_DEVICE
 fi
 
 LOGIDENTIFIER='btrfs-defrag'
diff --git a/btrfs-scrub.sh b/btrfs-scrub.sh
index 0f5bb75..557c87a 100755
--- a/btrfs-scrub.sh
+++ b/btrfs-scrub.sh
@@ -15,7 +15,7 @@ if [ -f /etc/default/btrfsmaintenance ] ; then
 fi
 
 if [ "$BTRFS_SCRUB_WAIT_AC_POWER" = "true" ]; then
-	wait_ac_power $BTRFS_AC_POWER_TIMEOUT "$BTRFS_AC_POWER_DEVICE"
+	wait_ac_power $BTRFS_AC_POWER_TIMEOUT $BTRFS_AC_POWER_DEVICE
 fi
 
 LOGIDENTIFIER='btrfs-scrub'
diff --git a/btrfs-trim.sh b/btrfs-trim.sh
index 04500ea..fe94d96 100755
--- a/btrfs-trim.sh
+++ b/btrfs-trim.sh
@@ -15,7 +15,7 @@ if [ -f /etc/default/btrfsmaintenance ] ; then
 fi
 
 if [ "$BTRFS_TRIM__WAIT_AC_POWER" = "true" ]; then
-	wait_ac_power $BTRFS_AC_POWER_TIMEOUT "$BTRFS_AC_POWER_DEVICE"
+	wait_ac_power $BTRFS_AC_POWER_TIMEOUT $BTRFS_AC_POWER_DEVICE
 fi
 
 LOGIDENTIFIER='btrfs-trim'
diff --git a/btrfsmaintenance-functions b/btrfsmaintenance-functions
index 529b183..96a3c94 100644
--- a/btrfsmaintenance-functions
+++ b/btrfsmaintenance-functions
@@ -77,28 +77,37 @@ is_btrfs() {
 	return 1
 }
 
+# function: check_power_status
+# parameter: paths to check the status
+#
+# Return true if at least one path is online
+check_power_status() {
+	local status=$(cat "$@" 2>/dev/null)
+	[ -z "$status" ] && return 0
+	case "$status" in
+		*1*)
+			return 0
+			;;
+		*)
+			return 1
+			;;
+	esac
+}
+
 # function: wait_ac_power
 # parameter: {timeout} {AC power online device}
 #
 # wait until ac power goes online
 wait_ac_power() {
 	local timecount=0
-	local timeout=0
-	local ac_power_device=/sys/class/power_supply/AC/online
+	local timeout=$1
 
-	[ -n "$1" ] && [[ $1 =~ ^[0-9]+$ ]] && timeout=$1
-	[ -n "$2" ]&& ac_power_device="$2"
+	while ! check_power_status "$@"; do
+		# AC is not online
+		[ $timeout -gt 0 ] && [ $timecount -ge $timeout ] && return 1
+		sleep 1s
+		timecount=$((timecount+1))
+	done
 
-	echo timeout $timeout ac_power_device $ac_power_device
-
-	if [ -f "${ac_power_device}" ]; then
-		while [ "$(cat ${ac_power_device})" -ne 1 ]; do
-			# AC is not online
-			[ $timeout -gt 0 ] && [ $timecount -ge $timeout ] && return 1
-			sleep 1s
-			timecount=$((timecount+1))
-		done
-		return 0
-	fi
 	return 0
 }
diff --git a/sysconfig.btrfsmaintenance b/sysconfig.btrfsmaintenance
index 871ab4e..1d259ac 100644
--- a/sysconfig.btrfsmaintenance
+++ b/sysconfig.btrfsmaintenance
@@ -15,10 +15,10 @@ BTRFS_AC_POWER_TIMEOUT=3600
 
 ## Path:        System/File systems/btrfs
 ## Type:        string
-## Default:     "/sys/class/power_supply/AC/online"
+## Default:     "/sys/class/power_supply/*/online"
 #
 # Path of AC status flag
-BTRFS_AC_POWER_DEVICE="/sys/class/power_supply/AC/online"
+BTRFS_AC_POWER_DEVICE="/sys/class/power_supply/*/online"
 
 ## Path:        System/File systems/btrfs
 ## Type:        string