Power up your Galaxy S4 with some Energi (hands-on)

We've all been there before: It's nearly the end of the day (or sometimes just the middle of the day), you're nowhere near an outlet, and your phone battery is all dried up.

But the next time you resign yourself to a drained battery, or send out a desperate "Sorry my phones about 2 die" text, consider a battery phone case like Tylt's Energi Sliding Power Case for the Samsung Galaxy S4.

Although Tylt makes power cases for the iPhone 5 and 5S as well, the GS4 model is the company's most recent addition to the Energi line.

Available for $99.99, the ensemble includes a slim-line case that snaps onto the handset itself, and the power slide case (which features a 2,350mAh battery inside). While the power case comes in one color (black), the slim-line piece comes in red, blue, and black.

To use, attach your GS4 to the slim-line case and slide it into the power case. Your phone will connect via a Micro-USB plug and will begin charging. To check the case's power status, press the button located on the back and an LED indicator light will flash.

Once connected, the case should give your handset about 90 percent of a full charge, or about 9 hours of extra talk time. You can always charge your case afterward through a Micro-USB port located on the case's bottom edge.

The device is coated with a soft, matte, rubberlike material, which gives the whole ensemble a slight rugged feel. But given the case's minimalistic aesthetic and simple lines, it manages to pull off looking pretty chic, too.

Like most battery phone cases, the Energi will add on a notable amount of weight and thickness to your smartphone. Unfortunately, the fact that the unit requires the extra slim-line case in order for your GS4 to fit with the Energi is a bit of a disappointment. That additional layer surely adds to the overall bulkiness, which is odd since the Energi Power Case for the iPhone or even for the Samsung Galaxy S3, does not require a slim-line accent.

It also takes a bit of muscle to dissemble the phone from the case. You'll need to push against your GS4 hard just to unplug it and slide it off. I wouldn't put much weight on this issue, however, since I've had similar experiences with the Mophie Juice Pack cases for the iPhone.

Considering how quickly smartphone batteries drain these days, especially with a handset of this size, a battery case such as this one is useful. True, it isn't the sexiest-looking accessory you can put on your device, but if you're ever in a pinch and your phone's at the end of its life for the day, you'll definitely value the Sliding Power Case's function over its form.