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on 18 September 2012
Anker® Astro3 10000mAh Dual 2A/5V USB Output & 9V/12V DC Output External Battery Pack Charger.

Edit Please note this is for the older version, NOT for the new E version (despite what the Amazon page says). Also I corrected my maths, as pointed out by Ms L Atkins. Thanks for that, I missed out some brackets!

So how many times can you charge your phone? This battery is 70% efficient (nothing is ever 100%). According to their website ( use this formula.

Capacity of the External Battery * 70% / Capacity of the Mobile Phone

So for my phone, HTC One V (1500 mAh battery) - (10,000 * 0.7) / 1500 = 4.66, or 4 full charges from 0% to 100% & 1 more charge from 0% to 66%

In testing I achieved 4 full charges from 0% to 100%, & 1 more charge from 0% to 54% before the Astro 3 was totally flat.

It took 2 1/2 hours to fully charge my phone using the S USB slot. It took 3 hours to fully charge my phone using the I USB slot.
(Using the wall charger that came with my phone, it takes 1 1/2 hours to charge my phone from 0% to 100%)

2 USB slots can charge up to 2A (@5V). USB Slot I is for Apple devices, USB Slot S is for Samsung (read Android) devices. Both slots work for any USB device I have tried that is 5V.
This also has a DC out slot that is switchable between 9V & 12V.

Your device will only draw UP TO the Amps that it is designed for. In other words if your wall charger is 1A 5V, it is ok to use this external battery, your device will only draw 1A. The external battery itself can supply up to 2A depending on your device, just make sure its 5V.

I also tried charging my netbook, an EeePC (1000HE) made by Asus, with an 8400 mAh battery that lasts for around 7 hours. The wall charger for this is 12V 3A. I was a little dubious about this as they say this device is not compatible with Asus tablets.

Anyway after 1 hour of charging, my netbook went from 3% to 32% & had 2 hours 15 mins of time on it. The external battery had 2 LEDs lit up after this, so between 50% & 75% charge left (I suspect just over 50%). The external battery was also rather warm, presumably my netbook was trying to draw 3A. I wasnt willing to try anymore because I didnt want to damage my Astro 3, but it will be ok for an emergency.

4 LEDs on the External battery to indicate how much charge is left. 1 LED 0% to 25%. 2 LEDs 25% to 50%. 3 LEDs 50% to 75%. 4 LEDs 75% to 100%.
This external battery comes with loads of different connectors that should fit most devices.

My phone (HTC One V) is about the same size an an iPhone 4. This external battery is a bit higher, a bit more wider, & twice as thick as my phone. Also considerably heavier. (Other reviews have measured this, I cba)

It arrived quicker than I expected, ordered on 7th Sept, was told estimated despatch of 13th for delivery 18th. It was actually despatched 9th, tried to deliver 12th but was too big for the letter box, & I had to pick it up from the Post Office 13th Sept.

I've added some pics showing the device with my phone.
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on 27 February 2013
This is a good product, it's not bad value for money, and having bought it I intend to keep it.

It's advertised under false pretences though, and here's why:

This charger operates at 5v (because USB power is 5v). But the batteries inside the device are only 3.7v... and there's some booster circuit inside which boosts that voltage up to 5.

When the manufacturer says 10,000mAh, they mean 10,000mAh at 3.7v. This is confirmed, as they say they use 37Wh of battery. Trouble is, when you have to boost this voltage up, your 'mAh' rating drops by the same amount.

So the device is only really a 7400mAh at 5v unit. The 10,000mAh is pure marketing, because really the customer shouldn't have to know or care about the voltages of the internal batteries!!

It's not bad value for a 7400mAh unit - but buyer beware!
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on 4 July 2013
I purchased this for the Glastonbury Featival last week. It charged my iPhone5 5 times and the Anker still had between 25% and 50% charge by the end of the week. Another great feature is the speed it charges your phone, just like its on mains. A must for any festival - especially at this great price
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on 27 February 2015
With more and more devices that need charging, this portable power bank will save you some headaches.

Very good build quality, battery cells, accessories.

Been going two years strong, no issues.

I've actually bought two more, and one of them was DOA.

That's when Anker really shined, with their incredible customer support.

You probably won't need customer support, but it's really reassuring they've got your back if you do.
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on 23 April 2015
I had problem with charging.Was loose micro usb port on pcb.When i open top cower i found that there 5000mAh batery inside.Model TPC 18.5Wh/3.7v 6259A0 5000 mAh.But model of batery pack.Anker 79AN7917 capacity:10000 mAh 3.7v. looks twice less capacity batery inside than declared on the body.Or i something not understanding :)
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on 27 June 2016
I had this item, and the input charge port absolutely died within a few uses. After I wrote a review, Anker themselves contacted me directly, and offered to replace the item, even though it was some time ago.
I was dubious to begin with, but then I received a newer version of this item, and in fact, a better one.
I was very pleased, and I have now been using it for some time.
I will review both in one, so that this may help any buyers in the future.
THIS model, was brilliant, and just slightly larger than my iPhone 6. It was quite a bit thicker, but it was a manageable size. In the box, i received the charger, a lovely little bag to carry it around in, and the charging cable. There was also the instruction manual.
I carried this charger around in my rucksack, and used it on MANY occassions, and I must say, it saved me quite a few times!
The charging port for the device on this was the only let down, as it broke after a handful of charges.
ANKER then sent me this model: Anker PowerCore 13000 Portable Charger - Compact 13000mAh 2-Port Ultra Portable Phone Charger Power Bank with PowerIQ and VoltageBoost Technology for iPhone, iPad, Samsung Galaxy
ANKER resent this model, which was MUCH better quality (in regards to the charging port) And lasted even longer for charging. I managed to charge my iPhone six times EASILY, and still had power enough left.
It is a nice compact design, and has lovely blue lights that show you how much charge is left in the device. It has an on off button, which is actually very useful! This also came in the box with the charger, the lovely net bag to keep it in, and the USB cable. You will need your own 3 pin plug though, which is my only niggle.
There is also the instruction manual, which is a bit bare bones, but also the feedback card, which should you have any problems, allows you to contact ANKER direct.
All in all, I would HIGHLY recommend the charger, especially with the amazing customer service that ANKER have. I cannot fault their customer service, and I know I would recommend these to any one of my friends.
Thank you for reading my review, and I hope it is helpful to you.
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on 24 July 2014
I'm very satisfied about this external battery.
It is very handy during conferences or when I'm moving a lot during the day and I don't have the chance to connect my smartphone to a power source.
The 10000 mAh capacity is enough for at least 4 charges of my Nexus 5 and the output (3000 mA) is very fast: it is easily possible to use the smartphone with highly consuming applications, such as GPS navigation, and still charging it using this battery.
I highly recommend it.
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on 9 April 2014
I spend much of my time out in the forests where I film educational videos (as well as generally just enjoying being outdoors). I film with a couple of GoPro cameras, which are charged via USB. This Anker battery pack easily charges them... even while they're recording with WiFi enabled!

There's plenty enough power in this battery pack to ensure I can record the maximum amount of footage the 64GB cards in both cameras can hold (over 16 hours of combined footage).

It is such an essential part of my recording gear, I keep it in the Pelican Case with the cameras.

More importantly, what this battery pack (even its baby brothers) represents is emergency power when you need it the most!

Last year I got into a spot of bother in the forest, and - due to injury - was unable to walk out to seek help. I was about 2 miles away from the nearest house... so shouting would've been futile.
In the finest tradition of "Sod's Law", my mobile battery decided it didn't want to hold a charge, so when I pulled my phone out of my pocket it wouldn't switch on. For a frightening moment, I thought I was going to be stuck there without help... until I remembered that I carry the brilliant Anker battery pack!
Plugged it in and immediately switched it on, with the Anker providing more than ample power to charge the phone while I used it. I called a friend to come and help me out, and didn't have to test my survival skills with one fractured ankle and a badly bruised knee.

It's not even £30! Every home and vehicle should have one of these ready to go at a moment's notice!

In October 2013 we suffered a severe storm which brought down trees and wiped out the power to tens of thousands of homes (including mine). I used the 12v output on this battery pack to power my router, and combined with a fully-charged Android tablet, I was able to find out how long the National Grid expected my area to be without power. I was also able to make Skype calls to locate a generator and get the lights back on before the first night fell (good thing, too, as power was down for 7 days).

Less than £30! Seriously... what are you waiting for?
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on 24 February 2016
I am and will continue to be a great Anker buyer and enthusiast. I have many Anker items that I use regularly. The company is excellent to deal with and products generally are extremely high quality. This one was an exception. For some reason, it refuses to charge properly. The maximum number of LEDs that will light up is three. When plugged in, they flash continually. In use, the pack drains very quickly indeed. There has to be a problem with the electronic circuitry - I have asked Anker for an opinion but to date they have not replied. My only option is to throw it away.
LATER: Anker read this review and contacted me. They offered to replace it and I had the updated model a couple or so days later. Service does not get any better than this. In all fairness, I cannot give my device 5 stars because it didn't work properly. However, based on the response, my experience of Anker across a wide range of their products, and accepting that I must just have been unlucky with the first one I received, I cannot in all conscience leave a One Star rating. Consequently, I am raising the rating to Four Stars. Thank you Anker. I very much appreciate what you did.
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on 19 July 2014
I needed something to keep my S4 going as a sat nav on a hire bike with no power outlet. This one is thin for the capacity; charges itself faster than most; at up to 2A; runs and/or charges devices from 50mA to 2A if they need it (thanks to PowerIQ); is more efficient than most external packs and comes with superb Anker build quality. Impressed. Comes with a nice protective textile pouch too.

Update. Wow, love this thing. It can fully recharge my Galaxy S4 Active's 2600mAh battery three times. That's really impressive, since the charging process itself is not 100% efficient - more charge must go into any rechargeable cell than you will get out of it - and the unit only claims 10,000mAh.

Many folk have criticised Anker for quoting 10,000 mAh capacity because that's the capacity of it's internal 3.7V cell and the unit will deliver less mAh at the 5V output level (i.e. about 7,400mAh, less any loss due to heat in the voltage conversion circuitry). However, in almost all case it will be used with a mobile device that steps the 5V back down to a single 3.7V cell, so a 7,400mAh capacity at 5V becomes more like a 10,000mAh capacity again at the end device's cell. And guess what, we mostly know the capacity of our phones' cells in mAh as rated at 3.7V...

Anker's, and the industry in general's, rating of external battery packs according to internal cell capacity makes it much easier to judge how it will perform when charging other devices that also use a 3.7V cell (i.e. almost every smartphone, most tablets, etc).

All you need to remember, as Anker point out, is that charging a cells is not 100% efficient, and neither is voltage conversion, in the external unit from 3.7 to 5.0 and in the end device back from 5.0 to 3.7 again. It seems that Anker must have excelled at reducing the losses in voltage conversion at their end (and conversion is unavoidable since all devices are design for 5V input), but the user must still account for perhaps 20% loss in the charging process for the target device. In my tests I could charge a good condition 2600 mAh cell in my phone three times, that's about 7,800mAh usable charge in the end device, or 78% total effiency including all voltage conversion losses (must be minimal!) and the cell charging process.

To keep it simple, just assume that this unit will typically recharge 70% i.e. 7,000mAh worth of target device 3.7V cells, or more if they are particularly efficient devices. This must be at least 10% better than many other devices with the same 10,000mAh rating.

What's more many generic unbranded devices exaggerate their cell capacities, so the end user will be ripped off and disappointed, but not so with Anker!

As for it's construction, it's very good indeed. Very solid with a nice glass like glossy plastic front (complete with protective film!) and a less smooth glossy back. The back appears like many modern devices to get it's glossiness by some form of coating or paint - their is visible orange-peel effect and the gloss rear picks up scratches more easily than the front. But heck, this is a utility device, so I'm not too bothered if the rear shows some signs of use.

The supplied textile pouch is really useful too, with a sort of "bounce" woven into it. Anker should sell those separately as they are offer really smart protection.

Unlike some devices, there are no internal permanently connected leads that stow neatly away. Actually, I think that's best, since (a) the size of the pack is optimised, (b) using target device;'s original charge leads is always recommended for fast charging and (c) it means any damaged leads can be simply replaced. The USB outputs and microUSB input should be very durable and give years of service - built in leads could be a weakness as well as adding bulk.

I like the way you can pop the unit in the supplied pouch, with one or two USB leads attached, gently pull the drawstring for good protection, but still operate the push-button and see the LED's through the mesh pouch. Very nice to use in a pocket, in a glove box, at the bedside, wherever. And because it's so efficient, it doesn't get hot when charging devices, which is a boon when it's charging from a pocket or such.

If I were to be picky, it would be neat of the pouch included a separate pocket for stowing device leads and keeping them away from the unit itself, just to keep it cosmetically fresh.

I'm growing to really like Anker devices, from un-boxing to living with them. Perfection is unattainable, but Anker seem to get very close while still coming in a a reasonable price.
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