Apple's Smart Battery Case comes from a company that seems to be annoyed that you want a battery case for your iPhone. The $99 case fits iPhone 6  and iPhone 6s ($169.00 at Amazon)  units, and it's the slimmest, barest battery case possible. It's made of flexible silicone with a soft, cloth-like interior, just like Apple's standard silicone cases. There's just now a bump for a battery on the back. But with its slender, grippy flexibility comes an unavoidable and unfortunate fact: The Smart Battery Case just doesn't have very much juice.

Design

The odd shape of the Smart Battery Case ( at Amazon) serves several purposes. The top is slim, so you can peel it back to slip your iPhone into the case. The bottom, meanwhile, is thin enough to fit into many iPhone docks, with the Lightning and headphone pass-throughs in just the right places. With most other battery cases, you have to take the phone out of the case to fit it into a dock.

The case's grippy, silicone feel is the best thing about it. Other plastic battery cases can feel slick and cold; this one feels comfortable in your hand and it always stays put—whether in your palm or on a table. It gives you confidence that it won't accidentally slip out of your fingers and onto the concrete. The case is available in either white or dark gray. I tested the white model, which looks like it could get pretty dirty over time.

I get that many people won't like the look, but I actually do. The matte silicone is traditional Apple, and it doesn't look cheap like some shinier metal cases do. The battery hump on the back is honest: It says, "This is an iPhone with an extra battery. What are you lookin' at?" 

The case charges via Lightning cable, as opposed to the micro USB cables most other battery cases use. While Apple sees this as a plus, I'm not as certain. Lightning cables are expensive and only work with Apple devices. Micro USB cables, on the other hand, are cheap and easily available everywhere. But then, you can slip a micro USB-equipped battery case on a Lightning-powered dock. It's a trade-off.

When you charge the phone in the case, you're charging the phone and the case simultaneously, as opposed to many other cases, which tend to charge the phone first. I don't love Apple's method, as I'd rather have the option to use the phone without the case when I can, or with a slimmer standard silicone case. You can do that faster when the phone charges before the case. 

Performance and Conclusions
There's no external battery indicator on the case. A single light inside the case turns orange when charging and green when full, but you can only see that when the case has no phone in it. To check the battery status when the phone is in the case, you have to drag down the phone's notification pane. That's pretty cool, but I would have still liked an external indicator so you can check on battery power without waking up the phone.

A battery case is ultimately about capacity, and that's where Apple falls short against other $99 cases. The 1,877mAh battery in the Smart Battery Case will charge an iPhone 6s to 81 percent, giving it an additional 3 hours, 23 minutes of usage in our extremely intense battery test (which streams video at maximum brightness over LTE).

That's shorter than any other similarly priced battery case we recommend. The Mophie Juice Pack Plus adds 4 hours, 53 minutes; the slim Mophie Juice Pack Air ($39.49 at Amazon) adds 4 hours, 21 minutes; and the versatile Boostcase ($12.98 at Amazon) adds 4 hours, 5 minutes. Anyway you look at it, the Smart Battery Case comes up short on power.

Apple might be making a calculation here that many people's iPhones start to run low on battery around 5 p.m., and that they don't charge them until around 11 p.m. (That's been my experience on busy days, like during the CES trade show). So the company has calculated a case that will last exactly that amount of time to keep the size as small as possible. 

Apple's Smart Battery Case for the iPhone 6/6s is the most comfortable battery case we've tested, thanks to its warm, flexible silicone material. But its smaller battery just doesn't provide as much assurance as competing cases, and it keeps you trapped in Apple's Lightning power ecosystem. For the price, we still recommend the Mophie Juice Pack Plus and the Boostcase over this one; the Juice Pack Plus will more than double your iPhone's battery life, while the Boostcase has a unique design that lets you ditch the battery part of the case when you don't need it. 

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