One of the most frustrating things about mobile devices is their insatiable demand for power. Besides giving nasty looks to those people hogging outlets at the coffee shop, you have other options that help you charge on the go. And the extra power can come in handy should the electricity go out during a storm.

For under $20, you can get a lipstick-sized charger. Bigger chargers that will still fit in your purse or pocket run about $30 to $50. For around $50 and up, you can get a mobile phone case with its own battery to supplement your phone’s battery. The chargers and cases are available from brands including Anker, Halo, Jackery, Lenmar, Poweradd and Phonesuit. The new credit-card-sized LithiumCard “hypercharger” promises to top up your phone quickly ($60). For tablets on up, you might consider bigger portable chargers from Hyperjuice and Poweradd, from around $130.

If you want to go plug-less, a wireless charging pad will create an electromagnetic field to recharge a device (from under $20). You may also need a charging cover for your phone. There are competing standards, including Qi and PMA, so you’ll need the right one.

Outside the home, automakers, including Toyota and Jeep, offer charging pads built into the dash. Back in the coffee shops, Starbucks, whose outlets are as coveted as its brew, has put wireless charging pads in some of its stores in Boston and Silicon Valley.


Cool Apps

In case of storms or other emergencies, your phone can help. Major wireless carriers are adding “text-to-911” capabilities under an FCC directive. While, carriers are required to send a bounce-back message if the text service is unavailable, it’s best to make a voice call if you can.

Besides texting, here are some emergency apps to consider:

The FEMA app offers disaster safety tips, an interactive emergency kit list, emergency meeting location information and a map with open shelters.

The Red Cross offers separate apps for first-aid advice and floods, tornadoes, earthquakes, hurricanes and wildfires.

Many localities offer emergency management apps, such as ReadySanDiego, so check your area.

The iMap Weather Radio app ($10) sends alerts wherever you are and wakes up your phone if it’s in sleep mode.

Pocket First Aid & CPR from the American Heart Association ($2) provides a first-aid manual with video and illustrations including a CPR guide.

Know Your Plan (Apple) from the Insurance Information Institute provides checklists to help you get prepared ahead of time.