Review: Anker Ultra Slim Battery Case for iPhone 6/6s

Anker Ultra Slim Battery Case for iPhone 6/6s











  • Has enough power capacity to recharge your iPhone 6/6s to full power.
  • Easy to use with a power button on the back.
  • Has a good feel and it's quite slim too.


  • Slow charging speed.
  • It's not protective has a normal case would be.

Battery cases are basically like power banks but they’re molded into the form of a smartphone to accommodate the smartphone that they’re compatible with.

So make no mistake, Battery Cases are indeed just power banks, but with a unique spin to them.

However, some may say that they’re actually more helpful than just power banks because a battery case is able to go over your smartphone just as any other smartphone case does, but this one actually powers it. And we’ve gotta say there’s really no beating that logic.

This is Anker’s Ultra Slim Battery Case for the iPhone 6 and 6s. Let’s see how good it is as a power bank case for your iPhone.


Power Capacity:

The power capacity for the Battery Cases starts at 2,850mAh and that’s not going to change very much.

Of course, it uses Lithium-Polymer batteries otherwise it wouldn’t be as slim as it is, but it’s mostly going to stay near its initial power capacity because of the slow charging speed.

As a result, you’re going to receive about 2,000mAh of Output power capacity that you can actually use.

This is great, and remember, we’re talking about a Battery Case here. It’s not meant to charge your smartphone multiple times over, just once is usually the max. In this case, that’s exactly what it does. The Anker battery case is able to charge your iPhone 6 and iPhone 6s to their full power capacities and still have just little left over to charge your iPhone 6 a little more.

It’s a perfect source of power for a battery case because if you’re halfway through your day, and need power, it’s right there with you. Simply turn on the battery case, and you’ve got another full charge going. Full all day.

 Anker Ultra Slim Battery Case for iPhone 6/6s 2,850mAh
(Output Power Capacity = 2,000mAh)
Phone CapacityAnker Ultra Slim Battery Case for iPhone 6/6s Left Over Capacity after One Charge

# of Full Charges for the Device
iPhone 62,000mAh1,810mAh190mAh Left Over

1.1 Full Charges
iPhone 6s2,000mAh1,715mAh285mAh Left Over

1.1 Full Charges

Output Charging:

We would have thought that since the Battery Case is made for the iPhone 6 and 6s, that it would have a charge speed to make match the devices. However, it doesn’t and this is because the Output charging speed is only 5V/1.0A. The max charging speed of the iPhone 6 and 6s is actually 2 Amps.

This is why we recommend you not to use the Apple wall charger that comes with your iPhone 6 since it only provides 1 Amp charging.

With that said, the Battery case will not be providing you with the fastest possible charge, but this is mostly because of its size and we’re guessing it doesn’t matter too much since the case itself is constantly on the phone.

Input Charging:

Also, just as the Output, the Input charging is the same with the recharging speed being 5V/1.0A.

As long as you’re using a 1 Amp wall charger to recharge the battery case through its Micro-USB input port (Which we find bizarre since Micro-USB charging cables are used to charge most Android phones, not iPhones, the use of a Lightning Input would have made a lots more sense.) the battery case will be able to be fully recharged within 2 hours.

Similar Power Bank

iPhone 6 / 6s Plus Alpatronix Battery Case


Size and Weight:

Okay, well there’s not much to say about the size because it’s basically the same exact size of an iPhone 6. It has a length of 5.5 inches, a width of 1.2 inches and a thickness of 0.16 inches. Also weighs very light at 2.9 ounces.

Functional Components:

The functional parts of the Battery Case are things that you need to know about before purchasing it.

It’s separated into 2 pieces, the top portion features the hole where the camera would be and the bottom portion is where the rest of the body of the iPhone 6 is. The 2 pieces are easy to connect, but first, you must have them separated in order to place your iPhone 6 into the Battery Case.

So the iPhone 6 will go into the large bottom portion of the battery case and then the top portion goes on top to click into place with the bottom piece.

So there isn’t a charging cable with the battery case because battery cases don’t use cables. Instead, they just use the charging head and in this case, there’s a Lightning charging head that’s going to be inserted into the iPhone at all times when the iPhone is placed into the battery case. This way, you’ll always have on-demand on charging.


This is done by pressing the power button on the Back of the Anker Battery case to turn it on and pressing it again to turn it off. There are 4 LED power capacity indicators as well.

At the bottom of the battery case is where there’s the Sound chamber opening to accommodate the sound chamber on your iPhone 6, as well as an audio jack opening. To use your Audio jack on your iPhone 6, the Anker battery case comes with an Audio Jack extender.

Finally, there’s the Micro-USB Input port at the bottom as well, but as we mentioned before, we think using a Lightning Input would have been better.

MaxBoost Atomic S iPhone 5/5s Battery Case


Structure and Material:

The battery case itself is made of plastic and it’s covered by a matte finish that makes it nice to hold. With that said, this isn’t a rugged or protective battery case and if you drop it, then it might get damaged. However, your iPhone will be safe, since the battery case also fills its purpose by increasing safety for your smartphone.


Not a lot of tech goes into a battery case because they’re just meant to be slim as possible to use with the respective smartphones that they’ve been created With that said, things can get a little warm with the battery case with its compactness but that’s the only technical build problems that we’ve noticed.


As we’ve discussed, this Battery case doesn’t have the fastest charging, nor does it have a power capacity to charge your iPhone 6 multiple times, and this mostly because it’s not meant for those kinds of things.

It’s meant to provide another full charge your smartphones and making sure that it lasts throughout the entire day while you constantly use your smartphones. Also, it makes sure that it’s as low profile as possible.

The Anker Ultra Slim Battery case achieves just that with its just power capacity and slim design.

Anker iPhone 7 PowerCore Battery Case 2,200mAh

Similar Power Bank



The power capacity is enough to charge your iPhone 6 or 6s to its full power. It’s not going to charge your iPhone at its max charging rate but it does well enough.


It’s designed very thoughtfully because the battery case has all its parts created to accommodate the iPhone 6’s design with its sound chamber and Audio jack opening. Anker even provides you with an Audio Jack extender to make sure that the battery case is easy to use as possible.


It’s not a rugged or waterproof battery case. With that said, if you do drop it on a hard floor, the battery case might break but your iPhone 6 will be safe.


A very reliable battery case for the iPhone 6 because it provides all of its aspects to make sure that it’s easy and powerful to use.

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Specs of the Anker Ultra-Slim Battery Case for iPhone 6/6s:

  • Capacity:            Advertised: 2,850mAh          Output Capacity: 2,000mAh
  • Output:   5V/1.0A
  • Input:     5V/1.0A Via Micro-USB Input
  • LED Power Indicators: 4 LED Dotted Power Capacity Indicators
  • Size: 5.5 x 1.2 x 0.16 inches
  • Weight: 2.9 Ounces


Battery Cases aren’t meant to be strongest, they’re not meant to be the fastest at charging.

What they are meant to be is being capable of providing a great design and having just enough power to charge the smartphone that they’re created for.

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