Stay in charge: 10 portable tablet chargers

Tablets typically have excellent battery life, but even eight or nine hours isn’t enough if you’re crunching quarterly sales numbers or planning PowerPoint decks on a cross-country flight, not to mention an intercontinental one. A portable external battery pack can keep you juiced up for your entire trip. However, just any old external battery pack won’t satisfy a power-hungry tablet. Luckily, these 10 tablet-optimized chargers promise to keep you working while far from an outlet. They’ll also charge your smartphone, and some can even give your laptop a lift.

New Trent’s iGeek iPad and smartphone charger is portable and lightweight, just about nine ounces. A little larger than most handsets, it charges an iPhone 4S in about 2 hours and recharges itself in 5.8 hours. The gizmo is compatible with iPads, the Samsung Galaxy Note, and the BlackBerry PlayBook. It comes with Micro- and Mini-USB cables, and works with all original Apple cables.

Battery capacity: 9900 mAh Price: $69.95, New Trent

Mophie’s Juice Pack Powerstation for smartphones and tablets is almost exactly the size of an iPhone 4S. This sleek charger features a skid-proof rubber-like surface and comes in black and red. It’s built to charge an iPhone 4 to the max in about two hours. The Juice Pack takes about four hours to charge, and feeds a variety of devices, including all iPads, the Asus Transformer Prime, and the Samsung Galaxy Note.

Battery capacity: 4000 mAh Price: $79.95, Mophie

Slightly larger than an iPhone, this pack comes with a special travel case and charges an original iPad or an iPad 2 in about six hours. The charger takes about eight hours to fully charge, and is compatible with a variety of devices, including all iPads, iPhones, and many tablets, though not with the Samsung Galaxy.

Battery capacity: 9000 mAh Price: $69.95, RichardSolo

PhoneSuit’s Primo Power Core battery pack for the iPad, iPhone, Galaxy Tab, as well as other Android tablets and phones looks sleek yet powerful. It’s a little larger than the usual smartphone but packs 8200 mAh capacity, enough to juice a handset four to five times. This should fill up an iPhone 4S battery in about 2.5 hours, and recharges in about 4.5 hours using a special AC adapter. It comes with a USB cable with interchangeable Apple, MiniUSB, and MicroUSB tips. A 12V out port lets it power laptops, with the order of a separate cable.

Battery capacity: 8200 mAh Price: $99.95, PhoneSuit

TYLT’s PowerPlant has a built-in cable, so you don’t have to carry around your device’s own USB cord. It comes in two flavors— one with a MicroUSB cable attached, while the other has a 30-pin Apple connector (not a lightning connector, so it won’t work with the iPhone 5). This 5.4 ounce charger also has a USB port, so you can use a separate device cable to charge your device as well. The TYLT is meant to take about seven hours to fully charge, and can energize an iPhone 4S in under two hours.

Battery capacity: 5200 mAh Price: $74.99 for Apple products, $69.99 for MicroUSB products, TYLT

Zagg’s ZaggSparq 3100 conveniently offers built-in prongs for wall outlets and can act as a wall charger. From its single USB port, the 3100 is billed to charge your devices up to four times faster than a typical USB charger. It’s compatible with almost all tablets and smartphones, but not with some newer tablets, such as the Google Nexus 7. However, it can only charge an iPad 3 to about 15 percent. Zagg’s charger weighs 4.6 ounces and is a little larger than an iPhone. Two other sizes include a 1220 mAh battery capacity, which can charge a smartphone once, and a 6000 mAh battery capacity to charge a handset four times.

Battery capacity: 3100 mAh Price: $69.99, Zagg

The myCharge Summit 3000 targets those who dabble in both Apple and non-Apple devices. Built-in USB cables include one with a 30-pin Apple connector and another with a MicroUSB connector. The Summit 3000 also has fold-out prongs, so you can plug it into the wall—this device lets you ditch the excess cables. This charge should take some four hours to fill up from the wall, powering up an iPhone 5 in under two hours. It’s compatible with all iPads and iPhones, as well as with multiple Android tablets and phones, and it can charge up to three devices at once. However, it’s bulky, slightly bigger than a deck of cards yet almost half a pound.

Battery capacity: 3000 mAh Price: $79.99, myCharge

This mobile power station is the highest-capacity battery on our list: 11,000 mAh. It’s also hefty, at a little over half a pound. The GearPower has two USB outputs, one for tablets (2.1A output) and another for smartphones and smaller devices (1A output), and it comes with a MicroUSB cable. The specs say it charges an iPhone 4S in around 2.5 hours, and can rev up an iPad 4 battery from zero to 70 percent capacity.

Battery capacity: 11,000 mAh Price: $79.95, IOGEAR

Energizer’s universal multi-port charger weighs half a pound and measures a bit smaller and stouter than an iPhone 4S. It features two USB ports— one for tablets, one for smartphones—magnetic cable clips, and an on/off button that lets you control charging. It comes with a MicroUSB cable, and fully charges in about six hours. This charger works with the new iPad and most Android slates. It also powers most smartphones, delivering a full charge up to four times.

Battery capacity: 5000 mAh Price: $65.99, Amazon.com

The slim Power Pack 4000 is about the size of an iPhone and can fill up two devices at once. It comes with two MicroUSB cables (for charging and recharging), and is compatible with a ton of devices, including iPads, iPhones, multiple BlackBerrys, and the Samsung Galaxy Tab 10.1.). The Power Pack 4000 is supposed to take about eight hours to fully recharge, and charge a smartphone up to four times and a tablet twice. However, its AC adapter appears clunkier and heavier than that of the competition (especially when some of the competition has built-in prongs for easy wall charging).

Battery capacity: 4000 mAh Price: $99.99, Belkin