New Trent Easypak 7000mAh Portable Triple USB Port External Battery Charger/Power Pack for Smartphones, Tablets and more (w/built-in USB cable)
I've been using this charger now for 2 years and it still holds a charge for long periods of time.  I can charge both my Ipad mini and my phone on it and it will charge both of them to full.  I've had it sitting in my bag for weeks before I pull it out and it loses very little of it's charge.  The quality of the product has been good, support has been good.  The one issue I had was with the charging cable.  The original cable fell apart, but after one quick email to New Trent, I received another cable in th