( CNN ) -- Thanks to a wave of new mobile technology , I can store my calendar , car keys , credit cards , music and notes all on my smartphone . That kind of convergence is convenient , but my phone has an Achilles ' heel . The battery does n't last forever . Enter the Powerbag , a line of battery-equipped shoulder bags and backpacks made by RFA Brands . It 's a smart backup for when gadgets inevitably need to take naps . I tested the Powerbag messenger bag for about a month , and I also spent a brief time using the backpack , which is very similar . On several instances during my tests , the bag proved useful on long trips or when traveling to conferences where I 'm constantly making calls or doing e-mail . I had to overcome a couple of concerns before strapping on the Powerbag . For one , the idea of carrying a battery about the size of a deck of cards on my back in the rain is not comforting . And this line in the Powerbag manual 's lengthy `` warnings '' section is not exactly reassuring : `` Improper use of this product may result in product damage , excess heat , toxic fumes , fire or explosion . '' `` Powerbag sources the highest quality cells and parts for the batteries , '' a Ful spokesman wrote in a reply to my worried e-mail . `` Our batteries are all rigorously and thoroughly tested , enduring the most abusive of treatment , still upholding Powerbag 's high standard of safety . '' When I considered that I keep my phone in my pocket near vital organs , the fear seemed less rational . The battery is stored in a zippered pocket at the bottom of the bag . I would n't take the bag on a whitewater canoe trip or a daylong hike under the blistering Egyptian sun , but the rain did n't faze it . My other hangup involved the annoyance of having one more thing to keep charged . I already charge my smartphone , tablet , laptop , iPod , computer mouse and Bluetooth headset . Now I need to charge my shoulder bag , too ? However , I was pleasantly surprised by how long the Powerbag 's battery lasts . It went for more than a week at a time retaining most of its charge . On a single charge , it can completely fill about two small gadgets -- a phone and iPod , for example . The bag includes three standard-size cords , including one that works with iPhones and iPods , and another that charges BlackBerrys , Mi-Fis and many Android phones . An iPod can be tucked into one zippered pocket while a BlackBerry can go into another , each filling with juice simultaneously . The Powerbag is able to charge an iPad , which is nice because many alarm clocks tailored to iPods and iPhones can not . But the tablet 's big battery sucks power more quickly , and it ca n't be fit securely anywhere for charging on the go . I was disappointed to learn that the Powerbag does n't provide an easy way to charge a laptop , which would have been useful for just a few more minutes of work on Wi-Fi at a coffee shop . A standard USB port is hidden in the battery pouch , so perhaps buying a USB-to-laptop charging cord would do the trick . An RFA Brands spokesman said that including a two- or three-prong outlet would require the bag to have a cooling system , which is something the company is not eager to do . There 's a conspicuous button on the front of the bag for checking the battery 's charge status : up to four small lights , which can be hard to see in daylight . I kept the bag 's charger tucked in a pouch inside the bag . The cap and charging port located on the side of the bag snapped off a few days after I started testing it , and so from then on , I had to take the battery out and plug the cord in directly whenever I needed to refuel . The RFA spokesman said this was only an issue with pre-production models , like the one I tested , and that it 's been fixed for the bags sold in stores . The Messenger Powerbag costs about $ 140 , same as the backpack , and is sold at some big electronics and office supply stores , including Best Buy and Office Max . RFA also produces bags with bigger batteries for about $ 40 more . There are several other travel bags on the market that have batteries inside , including ones that can be charged by sunlight using solar panels on the exterior . But most solar-powered bags look like an accessory that would have gotten a kid beat up in school . The Powerbag , designed by Ful , is stylish as well as useful , making it a good companion for gadgetheads who do n't want to advertise their geekiness .
We review Powerbag , a line of battery-equipped shoulder bags and backpacks . A full battery charge can fill up about two smartphones . Unlike solar-powered bags , you can hardly tell it 's a geek accessory . Powerbag spokesman : The battery was rigorously tested for safety .