uNu’s Ex-era Modular Battery Case for iPhone 4/4S ($80) is a pretty intriguing new charging accessory. This modular case ships with four main components: the main backplate, a colored frame, a flat back, and a removable battery-packed cover. The backplate and frame are designed to stay on at all times, with users swapping between the thinner back and the one equipped with the battery as desired. Part of the appeal is customization, as numerous colors are available. As with most battery cases, a Micro-USB cable is included to charge the 1700mAh cell.
Putting the iPhone in the case is easy. With the frame off it slides on to the Dock Connector and rests flat against the backplate. Then the bumper snaps on, holding the device in place and protecting the sides. It leaves easy access to the headphone port, mic, and side switch, as well as the unprotected buttons.
There’s no lip either, but uNu includes a sheet of screen protector film for protection. Because the Dock Connector port is in use, there’s a Micro-USB passthrough that is also used for charging the battery. It’s worth noting that the battery-equipped cover must be on to complete the circuit and allow charging or syncing. A grate about the width of Apple’s data plug allows audio through in both directions.
While Ex-era Modular Battery Case can be used without the battery when charging isn’t needed, the idea of using a case with exposed electrical contacts isn’t a great one. That’s why uNu includes a thin plastic back. Four posts on its underside slide into matching key-shaped holes on the case, snapping into place. We would’ve preferred if the hold was just a little more secure though, as it doesn’t take much force to push the plate up and off.
When it comes time to recharge, simply swap it for the back with the battery. If it’s off, press and hold the silver button on the rear until it powers on. That button doubles as a battery life indicator, trigging blue LEDs to its right. The difference in thickness between the two backs is actually pretty significant; it’s certainly a noticeable difference.
The thing that impressed us most about Ex-era Modular Battery Case was the battery performance itself. We were expecting the 1700mAh cell to provide a charge in the range of 75% to 80% range. In our testing with a Wi-Fi connected iPhone 4 not playing any media, a fully depleted battery rose to 91% in two hours and 32 minutes. This result is above average, and proves Ex-era to be one of the best percent per dollar cases we’ve seen.
