diff --git a/contrib/hooks/pre-auto-gc-battery b/contrib/hooks/pre-auto-gc-battery
index 6a2cdebdb78..7ba78c4dff6 100755
--- a/contrib/hooks/pre-auto-gc-battery
+++ b/contrib/hooks/pre-auto-gc-battery
@@ -17,7 +17,7 @@
 # ln -sf /usr/share/git-core/contrib/hooks/pre-auto-gc-battery \
 #	hooks/pre-auto-gc
 
-if test -x /sbin/on_ac_power && /sbin/on_ac_power
+if test -x /sbin/on_ac_power && (/sbin/on_ac_power;test $? -ne 1)
 then
 	exit 0
 elif test "$(cat /sys/class/power_supply/AC/online 2>/dev/null)" = 1