If you search for battery cases for the iPhone 4, you'll find that we covered quite a nice chunk of them on Gadgetmac. Some are slim while others are more protective, but what they all have in common is very similar battery performance at similar price tags. iBattz is a relatively newcomer in the battery case market with the Mojo battery case for the iPhone 4. The Mojo battery case is the first battery case we tried that has a user replaceable internal battery. Say what? You heard it right, the Mojo has a hot-swappable internal battery for sheer power charging goodness your iPhone 4 will thank you for. Just how well does all of this work out you ask? Find out in the full review right after the jump!

Let's get straight down to the nitty gritty. The only reason why you should get a battery case for your iPhone 4 is, of course, more battery life. If battery life means a lot to you, iBattz' Mojo has got the best solution to cater just that with its ability to triple your iPhone 4's battery life. That's a whole lot more than any other battery case we've reviewed until now. When you get a Mojo battery case, you also get two 1500mAh batteries the size of a smarphone's battery. These batteries aren't proprietary, in fact they are the very popular and readily available BP-4L Lithium Polymer batteries used by Nokia. That translates to 3000mAh of battery capacity to be used at your disposal. That's an impressive chunk of juice for the $79.99 price tag if you ask me.

Then there's the slight misconception with the whole triple battery life situation. Yes the Mojo is capable of lending you its massive 3000mAh of combined battery capacity, however, you'll have to always carry that extra battery with you. After that, it's simply a matter of sliding the back battery door cover of the Mojo to swap batteries. Does this method work? Yes, yes it does. It actually works better than I thought it would. Flawlessly I should mention.

Of course we haven't just taken iBattz word for it. We had to test their battery life claims in real world situations. So in my few tests in using the Mojo battery case with my iPhone 4, I was able to recharge my fully depleted iPhone 4 back up to a 90% charged state on a single 1500mAh battery. Is that impressive or what? I'll answer that for you, yes it is! It might not turn out to be a triple extension of your iPhone 4's battery life like iBattz has described it, but it's pretty damn close and certainly good enough. When you compare the Mojo battery case against the more popular Mophie Juice Pack Plus priced at $99.95 with a 2000mAh battery capacity, actually there is not comparing. The Mojo stumps any battery case Mophie made. I was able to use my iPhone 4 for just about 3 full days solely thanks for the Mojo for supplying the power. It's like having your very own Energizer Bunny.

It's worth noting that when comparing the build quality of the Mojo against any Mophie battery case, the Mojo does in fact have a lower build quality. Hey, at least its packs a punch. Not to mention the Mojo also comes with an extra frame in a different color so you can mix it up a little. Now that's what a call "bang for your buck". Also included is a USB cable to charge up the Mojo and will enable you to sync and charge your iPhone 4 as well. I found that you can also charge the Mojo battery case while the iPhone 4 is in it without coincidentally charging both devices at the same time.

Typical with almost all battery cases for the iPhone 4, the Mojo battery case has a contoured back with rounded corners that makes it very comfortable to hold. Plus the slim form factor just makes it a pleasure using. The Mojo comes in two colors finishes, a glossy white finish and a matte, soft-touch black finish. Depending on your preference, the black matte finish has much more grip because of the rubbery coating it has as oppose to the glossy finish of the white colored Mojo. 

I must complain about the idiotic decision someone over at iBattz has made regarding the side cutout for the volume buttons and silent switch. There is an unnecessary separation of the volume buttons which only makes it worse when you want to press on it. The cutout isn't wide enough to begin with. I've had no trouble accessing the top sleep/wake button and the headphone port though. I should also mention that it takes a little bit of force to remove the frame of the Mojo. It reminds me of how the Exolife battery case is designed. The back camera cutout is fairly large and will not interfere with taking photos.

As with any other slim battery case, the Mojo has no front protective edge to protect the screen of your iPhone 4. A small sacrifice for power, I say. Just like the PowerSkin, the Mojo has got only one multi-function button on the front of the bottom portion of the case that lets you check the remaining battery power and it also enables you to start or stop charging your iPhone 4. It's also worth noting that the small holes at the bottom do in fact muffle up the speaker volume a bit. Same goes for the mic holes. A bad move in designing only two small holes on each side.

When you consider the Mojo as your sole power source inside a protective case for your iPhone 4, it's no doubt that you're getting the most out of your money going with it. There is, of course, the matter of a few drawbacks that should be addressed by iBattz. Nothing comes close to the sheer battery juice the Mojo can supply. If that's what you're looking for, then I can recommend it. There's nothing like a removable battery case to fix your terrible battery life. Price $79.99.

iBattz.com