hi i have a car gps (tom tom one) that i would like to use on my motorbike (kawasaki gpx250). i can buy a mount from ebay, however how would i charge the gps? i have searched and people here mention doing an electrical mod. However i havnt found any instructions. can someone please point me to a tutorial? or better still is there an off the shelf product that allows me to charge my gps on my kawasaki gpx250? thanks!