Any gadget-loving traveler knows that there are never enough places to charge your gear while on the road. It often seems as though portable devices require more electricity to perform at the same level they do under normal circumstances, which is exactly why I bought a mophie to help my phone last through the day.
The juice pack air has a capacity of 1700 mAh, which is just above what the iPhone itself can hold. In other words, a little more than 100% extra power. It ships with a micros USB cable and a headphone adapter.
I never take my iPhone out of the case. Most of the time, I use it to keep my phone battery full during the day. I unplug around 6 in the morning and flip the mophie power switch on. My phone stays at 100% until the pack depletes itself, usually around 8 in the evening, depending on use that day. Then, I plug in to recharge the case.
To mix things up, I may keep the mophie turned off and use it just as a case. Then, if my phone gets low, I'll turn the mophie on to recharge it. Usually my phone goes from just a few percent to over 90% by the time the mophie drains completely, which is more than enough to make it through a single travel day or through 2 days of regular use.
I have tried several inexpensive battery case alternatives recently, but I have found that the $99 for the juice pack air is a great deal for the performance and reliability that it provides.
Earlier this year, mophie introduced the space pack, which has the same capacity as the juice pack air and also includes either 16 GB or 32 GB of extra storage. It starts at $150. I look forward to grabbing one of those the next time I'm in the market for extra power.