Review UNU Exera iPhone 4/4S Battery Case

We’re seasoned battery case users here at GS. No less than 6 iPhone battery cases have been flogged in-house, giving us a good breadth of information to reference whilst providing you with a perfect extended runtime solution. Today, we’re taking a look at the UNU 1,700 mAh Exera iPhone case. Can it really double your iPhone’s battery life (as so many case manufacturers incorrectly claim)? We’ll find out…


Most battery cases feature a built-in, non-removable battery. For all intents and purposes this is fine. Plugging into an external power source isn’t hard in this day and age. Still, the option of swapping out battery packs instantly makes a case more appealing. In the case of the Exera, such swapping is allowed thanks to the user replaceable, 1,700 mAh battery.

Thickness is a touch towards “too thick” in our opinion; our current favorite, the Incipio offGRID Pro feels much thinner despite featuring a body that is only a couple mm thinner (and a slightly lower rated 1,600 mAh battery too). Still, the size isn’t something that is going to prevent the UNU equipped iPhone from slipping into your pocket or small bag.

The UNU’s design is different from most in that instead of sliding your iPhone into a bottom piece and then having to slide a top piece over it (slider design), you slide your iPhone into it and then put a full-sized front piece over top of it. We kind of like this design better as it keeps the amount of line breaks in the case to a minimum.

On the back of the UNU you’ll find a single LED charge indicator and power button. For the rest of your iPhone’s buttons, simple cutouts are employed - nothing too fancy. Also, because of the nature of the case’s design, swappable front face plates are possible, and in fact, provided by UNU (for an extra charge). Additional colors including blue, red, silver black (and plenty more) can be purchased via the company’s website to give your battery case that added bit of flair and personality.

As we said above, the overall weight and thickness isn’t a deal breaker or overly burdensome. Still, compared to some of the other battery cases we had, the difference is noticeable. Keep that in mind if size is one of your more important considerations.


With 1,700 mAh of power on board, we were expecting a near-perect recharge, and at the very least, 90-plus percent from each recharge. And after a solid dozen and a half recharges provided by the UNU Exera, we’re proud to announce that the case can do just that.

The most stressful way to test a battery case is from a depleted state. We always drain our phones to < 5% and then activate the case to see how far it will bring it back up. The current put out by the case is the highest. Also, we continue to use our phones as normal (though, we do try to avoid sitting on our phones for multiple hours when testing). In the UNU Exera's case, hitting 90% was easy. Most of the time we'd get to the 92-97% range after a solid 2 hours and ~20-45 minutes.

If we went the other route and left the case on and allowed the phone to "sip" charge as it needed, getting through a 6am-10pm day was no issue at all, usually leaving us with around ~20% at 10pm with the case completely discharged.


It isn’t the fastest recharging case, the most capacious nor the thinnest. Still, UNU’s Exera iPhone 4/4S battery case has plenty to offer. It does have a nice design that makes the most (or less depending on how you look at it) of the case’s added girth. It doesn’t get too hot when recharging under load and it features some cool swappable front face plates for added user customization.

Overall a very solid choice for the discerning iPhone battery case user.


Gadgetsteria’s Rating: 8/10