Как добавить / в конце каждой сылки кромне основной использую стандартную ЧПУ вот мой .htaccess
Options +SymLinksIfOwnerMatch
# Prevent Directoy listing
Options -Indexes
# Prevent Direct Access to files
<FilesMatch "(?i)((\.tpl|\.ini|\.log|(?<!robots)\.txt))">
Order deny,allow
Deny from all
</FilesMatch>
# SEO URL Settings
RewriteEngine On
# If your opencart installation does not run on the main web folder make sure you folder it does run in ie. / becomes /shop/
#RewriteBase /
#RewriteRule ^sitemap.xml$ index.php?route=feed/google_sitemap [L]
#RewriteRule ^googlebase.xml$ index.php?route=feed/google_base [L]
#RewriteRule ^download/(.*) /index.php?route=error/not_found [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !.*\.(ico|gif|jpg|jpeg|png|js|css)
RewriteRule ^([^?]*) index.php?_route_=$1 [L,QSA]
