Australians are beset with an affliction being felt right across the nation. Nomophobia (no-mobilephone-phobia) is the fear of being without your mobile phone, such as when your battery dies.
Luckily, rechargeable devices can add more juice to your smartphone's battery when you're out and about. They're essentially a wall socket for your pocket, and can be very handy if you keep finding yourself with just 20% battery left by early afternoon.
What to look for
Size, shape, weight and capacity are the main things to consider when shopping for a power bank. A nice clear indication of available power is also useful, with some models showing a digital display in lieu of bars (e.g. "80% remaining").
Capacity, shown as a milliamp hour (mAh) figure, is a rough indication of the charging capabilities – the higher the number, the more power it can deliver to your device before the power bank also runs out of juice. Try to find one that can completely recharge your smartphone at least twice before requiring a recharge, as this should keep you covered for one to two days at a time. Most of the latest smartphones have a battery with around 3000mAh, so a 10,000mAh power bank should be able to charge the smartphone up to three times and a 20,000mAh power bank more than six times.
Size and weight
These increase with capacity, so while a 20,000mAh model may seem like a handy option, it may be too big for your pocket or bag. If you're looking to keep your phone charged at a one-day music festival, picnic or during a night out, look into a pocket-sized model with at least 6000–10,000mAh. Other situations, such as hikes that take you away from power for a number of days, may demand larger models, but these are usually too big for most pockets.
Shape and style
You may want to weigh up the shape and style as well. This isn't too much of an issue if you plan to carry the charger around in a bag, but weird shapes and bulky designs may be uncomfortable for your pocket. Try to find one that has a similar size and shape to a smartphone.
Portable power-banks are pretty standard devices designed for a single task. Some, however, include a few handy extra features such as the ability to charge more than one device at a time. This is particularly useful if you're out and about with the family and everyone has their own smartphone, for example.
Quick charge is another good feature to have on hand (if your mobile supports this feature), as is over-charge protection, which turns off the power bank once your device's battery is full.
Other extras include inbuilt torches and even jump-start kits for car batteries.
What they charge
CHOICE tested power banks with at least 10,000mAh, which can charge your dead smartphone multiple times, but also most smart tablets and other devices such as portable speakers, wireless headphones and compact cameras. They even support most wireless games controllers for consoles like the PS3/4, removing that dreaded feeling that bubbles up when you see the last charge bar flicker off in the heat of battle.
Some models pack enough grunt to power laptops, but we'd recommend you use this feature only if you're caught out without access to a power point or forgot your laptop charger. It's handy in an emergency, but not a substitute for your standard external power supply.
Although you can buy power banks for under $30, these cheaper models are generally under 3000mAh. You'll get one charge out of these at a time, if you're lucky. Most models can charge a standard 3000mAh device in around 90 minutes; any longer is a red flag. The power bank's recharge time isn't as much of an issue, as you can leave it plugged in overnight, but faster is generally better.
In our power bank reviews, devices ranged in price from $25 to $170.