diff --git a/functions/utilities.zsh b/functions/utilities.zsh
index 69fd2ec8..127007fb 100755
--- a/functions/utilities.zsh
+++ b/functions/utilities.zsh
@@ -9,9 +9,7 @@
 # Exits with 0 if a variable has been previously defined (even if empty)
 # Takes the name of a variable that should be checked.
 function defined() {
-  local varname="$1"
-
-  typeset -p "$varname" > /dev/null 2>&1
+  [[ ! -z "${(tP)1}" ]]
 }
 
 # Given the name of a variable and a default value, sets the variable
diff --git a/powerlevel9k.zsh-theme b/powerlevel9k.zsh-theme
index ab56d234..f3126b81 100755
--- a/powerlevel9k.zsh-theme
+++ b/powerlevel9k.zsh-theme
@@ -498,7 +498,7 @@ prompt_battery() {
     fi
   fi
   # return if POWERLEVEL9K_BATTERY_HIDE_ABOVE_THRESHOLD is set and the battery percentage is greater or equal
-  if [[ -v "POWERLEVEL9K_BATTERY_HIDE_ABOVE_THRESHOLD" && "${bat_percent}" -ge $POWERLEVEL9K_BATTERY_HIDE_ABOVE_THRESHOLD ]]; then
+  if defined POWERLEVEL9K_BATTERY_HIDE_ABOVE_THRESHOLD && [[ "${bat_percent}" -ge $POWERLEVEL9K_BATTERY_HIDE_ABOVE_THRESHOLD ]]; then
     return
   fi