there are different wys for that.for example leafpad.
i use midnight commander.its a good working file explorer with many functions.
download it go xterm.
type
root
mc (thats cause midnight commander needs root to edit system files)
then go to your conky conf tap on edit,erease the old code tap on the upper bar and push "paste" (you have to copy james code first)
then exit and don't forget to save,type this in xterm:
sudo gainroot
echo bq27x00_battery >> /etc/modules
reboot and you are finish