Hello everyone! First post here. So, my Xperia Arc battery simply doesn't last more than 10 hours if I'm using it, so I was looking to buy spare batteries and a separate charger for them. Started searching on ebay and was surprised about hoy cheap some of these are... but I'm not sure if buying would be safe for my phone? I'm talking about this exactly: http://www.ebay.com/itm/New-2pcs-BA...ps=63&clkid=8484663691210962906#ht_4595wt_952 So what do you guys think?