Anyone who’s ever taken their iPhone on a road trip has at some point yearned for a little extra juice along the way. In the middle of a cross-country flight, or in the middle of nowhere in the backcountry, a back-up power source isn’t just a handy extra, it can be a necessity.

Here are a few options to give you a few more hours of GPS-assisted navigation on your hike, one more run through Flirtin’ with Disaster on I-95, or an extra hour of Edge before the plane lands. All of these battery cases not only boost your iPhone’s staying power, but they also provide extra protection and some enhanced functionality.

The Pretty Boy: Mophie Juice Pack

With its clean lines and snappy colors, Mophie’s Juice Pack ($80) has the kind of looks you wouldn’t mind showing around the office. The matte texture helps gives the phone some extra grip, but the case also completely wraps around the iPhone, acting as a fully protective sleeve. I dropped my Mophie-encased phone several times on concrete and tile without scratching it. It just about doubles the iPhone’s battery life, so you blow through a few seasons of American Dad before you kill the battery.

The Juice Pack gives you the option of using either the iPhone’s battery or the spare battery first. If you opt to run down the iPhone’s battery first — which is recommended, as being on a constant charge takes energy — just flip the switch on the bottom of the case to stand-by mode.

The case needs to be attached to the iPhone to charge. The case is a bit bulkier than most protective cases, but it’ll fit into all but the skinniest of skinny jeans.

Mophie.com, $80

WIRED Good-looking. Doubles battery life. Drop-worthy protection.

TIRED Too bulky for some hipster pockets.

Rating: 8 out of 10

The High-Miler: Sol Hybrid Power Pack

Sol’s case ($90) is not only the longest-lasting battery case in this lineup, it’s also the only one with a solar panel to let you charge the phone au naturel.

It’s also remarkable as a speed charger. When the battery inside the case is fully charged, it can juice up your phone extremely quickly — it charged my dead iPhone 3Gs in under an hour, rather than the standard 3-hour charging time through a wall socket. But if you just leave the phone in the case all the time and let the power trickle in as needed, it can triple the life of your iPhone. It kept my iPhone alive through a 12-hour trip to the summit of Mt. Shasta. It would be great for a century ride, especially if you plan on using your battery-sucking GPS all day, or even if you just want to stay connected so you can Instagram the whole thing.

When both the phone and the case are depleted, the Sol Hybrid case can charge up not only with sunlight, but also with artificial indoor lighting. Be aware that fully recharging the case’s battery, even in full sun, is an all-day task.

The Hybrid is the least protective of the cases, however. It’s a bit thicker than the Mophie Juice Pack, but it doesn’t fully cover the top of the iPhone. If you drop it and it lands top-down, you could be hosed.

Solmarketplace.com, $90

WIRED Monster battery life extension. Solar charger provides energy in emergency situations. Speedy iPhone charge. One unexpected, yet welcome, feature is the LED flashlight on the bottom of the case.

TIRED Not as protective as other options. Solar charger is too slow to be used for anything other than emergencies.

Rating: 8 out of 10

The Tank: Magellan ToughCase

In the iPhone playground, the Magellan ToughCase ($100) would take the other cases’ lunch money.

Big and burly, the Magellan’s key strength is its durability. In Yosemite, I dropped the case a few times, even kicking it into a stream when trying to balance the iPhone camera and a water filter. My phone came out of the woods safe and sound.

In addition to protecting your iPhone against everything from gnarly drops to total submersion, the Magellan also sports an extra boost of juice for your phone, roughly doubling your battery life. That’s decent, but other cases offer more longevity. It also tightens the GPS accuracy to about 10 to 15 feet. That’s not a huge advantage over the iPhone’s 21 feet, but if you’re adventure racing, or if you’re a geocacher who doesn’t mess around, the Magellan can give you an edge.

It’s definitely too bulky to serve as an everyday case for city slickers, but when you’re going to be in the wild, or if you work in construction, the ToughCase will keep your iPhone safe and powered up.

MagellanGPS.com, $100

WIRED Makes your iPhone almost impervious to harm. Increases the accuracy of the GPS reading to about 10 to 15 feet. Doubles battery life. If you’re in bear country, the Magellan can be used as a weapon when placed in a tube sock and swung overhead.

TIRED Freaking huge.

Rating: 7 out of 10

The Magellan ToughCase is big, but it takes a beating.

Photos by Ariel Zambelich/Wired