Wanted peddles for scooter BATT. upgrade

WANTED: Peddles and peddle arms for electric scooter E-mail SILVERFL39 [at] YAHOO.COM What does 408 mean? And has anybody added 2 more batteries to a 48volt system without any other mods for a total of 72volts? My controller says 600wats can it handle it? My batts. are 4 12volt 12 amphr. Or should I add 2 12volt 7amphr batts? Please help