We have a serious fetish for portable battery packs, power banks, external battery’s or which ever you choose to call them. We have showcased the New Trent 12,000 mAh power bank, the Anker Astro 3, Anker Astro 3e and a slew of other power options that can help you get the most out of your device when there isn’t a physical power plug or supply available to you. Our history with Anker has afforded us the chance to take a closer look at their latest power bank, the ultra slim Astro Slim2. It is amazing to see how power banks, battery size, design and pricing has progressed over the last couple of years. The Astro Slim2 is the perfect example of how things can move forward and not break the bank account at the same time.

Whats in the Box

  • Astro Slim2 4,500 mAh power bank
  • Micro USB data cable
  • Micro USB – mini USB adapter
  • Micro USB – Apple 30-pin adapter
  • Instruction manual

Anker Astro Slim2 4500 mAh power bank Review
One thing I have also personally loved about Anker is their dedication to making sure their power banks come with everything you need, for most devices you own, to start charging right away. The Slim2 is no different. With Android heavily reliant on Micro USB charging cables, their products are ready to go out of the box without additional purchases or the need to find a spare cord. Not that any Android user out there doesn’t have a few extra USB cables sitting around.

The Internals of the Astro Slim2

Obviously the Slim2 is a portable power bank. It ranks in with a 4,500 mAh built-in battery. That should offer most phones 2 – 3 full charges while on the go. Some of that will depend on your device, if you are using it to stream movies while charging and various other factors. In the case of devices like the Samsung Galaxy Note II for instance, you should get a full charge plus maybe a little kicker as the internal battery of the Note II is 3,100 mAh. The output on the power bank is 5 Volt 1 Amp which will give your device a ‘quick charge’ as it is called. As an example, I plugged my S III in at 54% and set them on the desk. I went from 54% to 67% in 18 minutes. A 13% jump in a short amount of time. It is already at 72% in the last 10 minutes.

Anker Astro Slim2 quickcharge image Anker Astro Slim2 quickcharge image Anker Astro Slim2 quickcharge image

The Externals of the Astro Slim2

Internal power and specs are a good thing to know, but the design and functionality of the Slim2 are what makes it a compelling device to want to add to your gadget collection. Externally most people want things to look stylish, be small, and make life easier when ever possible. The Slim2 delivers all of this check out the physical specs get a good idea of the size of this power bank.

  • 5-inches long
  • 2.5-inches wide
  • 0.4-inches thick
  • Weighs 4 oz

To compare it to something else that a great number of you have held, have used or owned, I snap some shots of the power bank sitting on, above and next to my Samsung Galaxy S III. The S III specs are 5.38 x 2.78 x 0.34 in and weighs 4.69 oz. Take a look.

Anker Astro Slim2 4500 mAh power bank Review Anker Astro Slim2 4500 mAh power bank Review
Anker Astro Slim2 4500 mAh power bank Review Anker Astro Slim2 4500 mAh power bank Review
As you can see, the Slim2 is slightly smaller in length and width, and barely noticeably any thicker. Weighing slightly less than the S III makes connecting your already slim and light devices to the Slim2 and putting them both in your pocket pretty easy. It also makes holding them both together to take a call pretty effortless as well.

You will also notice that the power bank offers one built-in Micro-USB charger. That is tucked nicely inside the charging port. Grip it and pop it out and plug-in your phone. Anyone that has a 2 foot long charging cord connected to a power bank knows how annoying a long cable sticking out of your pocket can be. This small addition to the Slim2 extremely convenient to have around. With the included Micro USB to 30-pin and mini USB adapters, you are pretty well set for power for your device, and the occasional friend that might own ‘the other guys’ products.

Anker Astro Slim2 4500 mAh power bank Review Anker Astro Slim2 4500 mAh power bank Review
On the other side of the Slim2 there is a standard USB port. Simple explanation  this lets you charge a second device at the same time. Obviously we don’t have to tell you that would mean a higher drain on the battery and you might only get one full charge per device. Yes, we told you anyways.

On the top in the middle you will find a series white LED lights. There are a total of four and there to indicate how charged the battery is when it is charging and also how much charge is left when charging your phone. Four lights is 75% to 100%, three lights 50 to 75% and so one. You get the idea. It is your typical general power meter.

Anker Astro Slim2 4500 mAh power bank Review
Anker says the outer shell is made of a non-slip material. While it certainly isn’t as slippery as the S III is, it isn’t rubberized by any means. It is more of a matte finish.

What I liked most about the Anker Astro Slim2

It is small, compact and easy to use. I don’t have to worry about packing a charging cable since it has one built-in. Being able to charge two devices at the same time is definitely nice, especially if you have an MP3 player or work and personal phones that you carry often. Not having to worry about an on/off button or switch is nice as well. The Slim2 automatically turns on when you plug something in and shuts off when it isn’t connected to anything.

What I didn’t like about the Anker Astro Slim2

The additional adapters are nice, but they are small connectors. It would be very easy to lose them. Anker doesn’t provide any means of transporting the power bank, connectors and small cable. It would be nice to have a small nylon style branded draw string bag. The USB port being on the side vs the top or bottom poses an interesting issue if you are trying to charge a device in your pocket using a different cable. It would be just fine for table top charging, and of course for charging a second device, which you wouldn’t put all three in your pocket to begin with. However, this got me to thinking why you would use a different cable to charge your device. Other than possibly using a longer cable to keep the battery in your pocket while just using your phone. If it is because you need to charge your mini USB or iOS product, you would just attach the connector to the built-in cable.

Other useful information

  • Charging from a PC or Laptops USB 2.0 port could take as long as 10 hours to charge up the power bank.
  • The kit does not include an AC wall adapter, not an issue since you can use your current devices adapter.
  • It can be recharged 500+ times and comes with an 18 month warranty. If you use it daily, you have about a year and half of life. 
  • While rated at 4,500 mAh, you have to consider charge loss during the charge process.  Estimates place it between 70 and 80% usable power. So 3,150 mAh to 3,600 mAh. 

Final thoughts

If you find your self running low on battery, searching for chargers, power plugs or a PC to juice up frequently, then you should consider picking this product up. It delivers what it says it will and looks good doing it. Typical power banks we have seen in the past in 5,000 mAh range can run you upwards of $60, easily. Many of which don’t give you any addition cords or adapters. The Anker Astro Slim2 is coming in at a modest $27.99. That means you can get one and sacrifice one pizza night to afford it. If you have the cash now, click the Amazon link below to go get one ordered today. While you are there, take a look a some of their other products, or visit their website at ianker.com

Anker gave me this product in exchange for my honest feedback

  • FILA

    1A output, not enough, and only 4500mah. Why cant anyone get it right!

  • http://www.external-battery-charger.com Kevin

    Nice review Stormy,

    In Germany is this Product not available, but i hope i can test him too in the next time.


  • http://www.accemobile.com mobile accessories

    Very Good, i like it!