As an iPhone owner who likes to use the phone a lot, I’ve been struggling to find a solid external battery situation for those times when I can’t be near a power source (home, office, car, lunch buffet at the strip club, wherever). I’ve tried plenty of solutions and shelled out a bunch of money, but didn’t come up with anything I really liked. Kensington makes an external battery pack, but that required taking off my iPhone case and it felt like it was going to snap off. I tried the Incase Power Slider, but my signal dropped so much that my iPhone sat at “Searching” inside my house where I normally have 4 bars of 3G. Last week, I got my hands on the Mophie Juice Pack Air, a combination case and battery pack that claims to double the battery life of the iPhone. Does it win the war of the iPhone battery packs? Short answer: yes.

On a daily basis, my iPhone 3G sits in an Incase Slider hard case. But on days when I know I’ll be out for a while or want to rock some extensive gaming, I know I need something else. The Mophie Juice Pack Air definitely has the battery life it claims. I normally get about 4 hours of usage time before dropping to a Low Battery Warning. With the Juice Pack Air attached, I got right around 8 hours of usage time (neither times include standby time). You can easily turn the Juice Pack Air off if you don’t want to use the battery as well as see how much juice is left by pressing a button on the back of the case. The best part, for me, was that signal was barely affected. I hovered between 3-4 bars of 3G coverage where I normally sit at 4 bars in my house. Any battery case is going to affect the signal, but Mophie does the best job of minimizing that effect so it doesn’t cause any hindrance to your day to day use of the phone.

The case it’s that big, either, which surprised me. It does make things heavier and bulkier, but you can still carry it around in your pocket without feeling like there’s a brick down there. The case and iPhone can be charged with the included microUSB cable, as well as syncing your iPhone with iTunes, which is a plus. The only downside is not being able to use the dock connector, if you have any peripherals that take advantage of that port.

For long trips or just extended use of your iPhone, I highly recommend picking one of these up. It has come in handy and saved the day for me quite a few times (like last night when we rescued Karl and I wanted to take pictures to post to Twitter and Facebook). Based on all the battery packs I’ve tested, Mophie’s Juice Pack Air is hands down the best on the market.