add the following to your crontab:
*/10 * * * * mkdir -p /tmp/pactmp && fakeroot pacman -Sy --dbpath
/tmp/pactmp
not even sure if it works though... no new packages to test it with
Kernel: ${alignr}${kernel}
Uptime: ${alignr}${uptime}
# |--Updates
Kernel: ${alignr}${kernel}
Uptime: ${alignr}${uptime}
# |--Updates
-Updates: ${alignr}${font Droid Sans:style=Bold:size=9}${execi 10800 pacman -Qu | wc -l}${font} Packages
+Updates: ${alignr}${font Droid Sans:style=Bold:size=9}${execi 600 pacman -Qqu --dbpath /tmp/pactmp | wc -l }${font} Packages
# |--CPU
${font Droid Sans:style=Bold:size=12}${color 75D1FF}CPU${color 1B71CC}$hr${color}${font}
# |--CPU
${font Droid Sans:style=Bold:size=12}${color 75D1FF}CPU${color 1B71CC}$hr${color}${font}