I'm thinking about purchasing these two batteries plus a wall dock charger. What do you guys think? I would like to have extra spare of batteries on me so I won't have to worry about putting my phone in the car charger while I'm out and about doing my thing. HTC EVO 4G SPRINT 2x1800 mAh Battery+Dock USB Charger - eBay (item 220648053953 end time Sep-02-10 10:08:30 PDT)