Most helpful critical review
124 of 144 people found the following review helpful
Nice design and size but subpar charging capability, long charging time, and price inflation.
on April 28, 2012
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 (62.85%). This means ~28% - ~37% of its 8400mAH capacity is unusable. I predicted at least ~20% of 8,400mAh is powering itself which is 1,680mAh and perhaps some energy is loss through heat. I concluded that the circuitry work on it is not as good and/or the lithium ion battery isn't of "higher" grade technology (ie. Panasonic & Sanyo 18650). It fell somewhat below my expectations regarding its most important function. However, I do have an Incredicharge I-11000 with 11000mAh capacity and it is about 65-70% efficient but much bigger in size. Perhaps this is the best we can get with portable battery technology. Another alternative is to buy a high quality spare battery(ies) specifically for your cell phone as 100% of it's rated capacity will be used to power that device. Though, this is not achievable with Apple products or others without removable batteries and that this method can be expensive and impractical if you plan on buying many different batteries for various products.
Time to Charge Anker 8,400 mAh: It takes nearly 8 hours to charge with the included cord and adapter. DC input is rated at 5v/1.5amp which is good, however, the included wall adapter is only 1amp. So the charging could have been quicker if it was included with a 1.5-2amp usb wall charger. Would definitely not charge this thing via a computer (.5amp). By pointing this out it does not mean it's a pro or con since it is accurately stated under product description.
Design: Very nicely polished and sturdy case. USB ports and LED light function as described without any problems. The case is the size of a bridge sized Bicycle cards. Easily carry with you where ever. It is dense and not hollow so I would say it is high quality.
Mislabeling: At the time of ordering Anker Astro 2 I noticed it indicated the 2 USB port is rated at 1amp & 2amp. However, upon receiving the package it is clearly 0.6 & 2amp. 0.6amp is adequate for phones but that is 40% slower than 1amp. I believe another customer has pointed this out in an earlier review. It appears they have fixed this error.
Price: I purchased this mid April for $46.99 but now it is $49.99. Still not a bad deal but price inflation due to more stellar reviews isn't cool. I noticed some feedbacks were left by those who has gotten a free sample for review, could there be a correlation in price increase and demand based on reviews?. Just wanted to let you know the Incredicharge I-11000 I purchased in March went from $49.99 to $79.99 in a span of 1 month. Now I cannot even search for this product on Amazon.com anymore.
Customer Service: LaptopMate replied to emails quickly and seems very concern about customer satisfaction. Their 18 months warranty is the most of all power bank I researched.
Conclusion: Astro 2 is very convenient device that comes with plenty of adapters (btw, it doesn't come with Apple adapter so use your own). I like the idea of charging on the go but plan ahead to charge the Astro 2 as it takes very long. You can considering looking at the Powergen 8400mAh battery which is an identical replica of each other and same price but the Powergen comes with an Apple adapter. It seems like somewhere in Shen Zhen or Guandong China they make these without branding and you can get them in bulk with customization for advertisements. Ebay "Power Bank 8400mAh" and you will see plenty of clones but they have short or no warranty. I hope this review has been helpful to the readers.