TestFreaks tried the Poweradd Pilot X1 5200mAh Battery Charger
A quote from the article:
I?ve got a quick review for you today of a small portable battery from Poweradd called the Pilot X1. This battery is 5200mAh in capacity and should provide about two charges for most phones out there today. The Pilot X1 is small and portable, really pocket size and it's well made and best of all it's inexpensive coming in at under fifteen dollars. The Pilot X1 has a single USB port on it for charging but it also has a built-in LED light so it would be great for emergency situations or taking it with you on a hike or camping. Read on to learn more?Poweradd Pilot X1 5200mAh Battery Charger Review @ TestFreaks