[Upgraded Version] Anker® Astro2

[Upgraded Version] Anker® Astro2 Dual USB Output 8400mAh Backup External Battery Pack Charger with built-in Flashlight for iPhone 5, all iPhone, iPad, iPod models; Android Smartphones: Samsung ... 4.8 out of 5 stars CONSUMER REVIEWS(184) Deal Price: $79.00

Description Anker - Extend limits Anker focuses on portable energy field, provides rechargeable batteries, chargers and other accessories for consumer electrics. Now Anker brand is associated with high performance and reliability. Popular Compatible models Apple: iPhone 5 (OEM cable required) / iPhone 4S / iPhone 4 / iPhone 3GS / iPod Touch Classic Nano / iPad / iPad 2 / iPad 3 HTC: One X / One S / T-Mobile Sensation 4G / Sensation XE XL / Radar 4G / EVO 3D 4G / Inspire 4G / Vivid 4G / Wildfire S / ThunderBolt / Incredible 2 S / Rezound / Desire HD S Z Samsung: Galaxy S3 / Galaxy S2 / Verizon Galaxy S3 S III I535 / AT&T Galaxy S3 III I747 / Sprint Galaxy S3 III L710 / T-Mobile Galaxy S3 III T999 / Galaxy S II I9100 / T-Mobile Galaxy S II T989 / AT&T Galaxy S II I777 / AT&T Galaxy S II Skyrocket SGH-I727 / Sprint Galaxy S II Epic 4G Touch / Galaxy Nexus Prime / Galaxy Note / Focus S / Infuse Motorola: Atrix 2 / Triumph / Photon 4G / Verizon Droid 3 X X2 Bionic Razr LG: Vortex / Revolution / Quantum / Optimus V S T 2X 3D 7 Nokia: N900 / N9 / N8 / N97 / Lumia 900 800 Others: Blackberry Bold 9900 / Sony Ericsson Xperia Arc S / 3G 4G mobile WIFI hotpot / PSP / PS Vita / Nook Color / MP3 MP4 MP5 / GoPro / Amazon Kindle Fire Note: 1. When you get the battery, you may find there are scratches on the surface of the product, which is the normal state of the protective film. Just peel it off before use. 2. Many Apple devices must detect a custom USB pin design before they will properly charge. The Anker power wire is custom designed to ensure compatibility between Anker Astro and your Apple device. Using your own wire may result in slow or even no charge. Please use the Anker power wire provided After using this battery pack for about a week, I make the following observations, in order of personal significance:1. Build quality: The battery pack feels, in a word, solid. There is no flimsy plastic deflection if you press on it and no creaky or uneven seams.2. Looks: The pack looks great. Yes it is a fingerprint magnet, but it also wipes cleanly to a beautiful gloss to match most smartphones out there.3. Utility: Very versatile. One port for smartphone and most usb powered gadgets, the other higher amperage port for more power hungry devices, like tablets. I've even used this to charge AA batteries with a usb AA charger. There's nothing I've tried that this won't charge. Also has a built in led "flashlight," but more on this later.4. Convenience: This pack will charge easily with any usb charger. Standard micro usb connector means you won't have to go searching for a special cable to plug this in and charge it. This pack... Here is my unbiased review of Anker Astro 2 8400mAh external battery pack:Charge Efficiency: Its rated at 8,400mAh as it's capacity. The lithium ion battery may have that capacity but it's ability to charge other devices isn't so hot. I understand the Anker power bank needs power of its own to operate and conversion from 3.7v to 5.0v takes energy. I wasn't expecting 100% of 8,400mAh to fully charge into other devices totaling up to 8,400mAh. But I was expecting it to be efficient. I did 5 charge and discharge cycles (though it may not be necessary on lithium batteries but I did it anyways to calibrate it) then I went on with my test to see how much it can charge my Kindle Fire, HTC Evo 3d, HTC Evo, Kindle reader, and portable speaker. Yes, the devices I were charging were completely off to preserve energy for charging only instead of also powering it on. The first charge cycle it totaled 5,425mAh (64% efficiency), 2nd is 6,032mAh (71.81% ), and 3rd is 5,280mAh... Lots of devices need more than 1A to charge but there are very few battery packs that will put out that much current. In fact there are few 12V-5V converters that will do that. This battery pack has both the capacity and current output (2A) to charge pretty much anything that takes 5V - phones or tablets. I like the charge indicators and also the flashlight, for emergencies. The instructions were in both chinese and english - and they were adequate. I tried the battery on an iPhone, Kindle Fire and HP Touchpad. All charged correctly. Note that there are two USB outputs - one is limited to 0.6A and the other to 2A. Use the higher current for tablets.