you can change the max lifetime for a session with the function ini_set().
<?php
ini_set("session.gc_maxlifetime", "18000");
?>
This will set the max lifetime of the script to 5 hours. You have to use this in every script that you want to change the default lifetime for.
if you want to know the lifetime of your current script, you can use:
<?php
echo ini_get("session.gc_maxlifetime");
?>
