Smartphone screens are getting larger and Australians are relying on their mobiles more than ever. Making sure your device stays powered is essential, and that's where a power bank comes in.
Rechargeable power banks provide more juice for your smartphone battery when you're out and about – something that's especially useful if you're finding yourself with just 20% battery left by early afternoon. Here's what to know if you're in the market for one and how to make sure it suits your needs.
What can power banks charge?
These battery packs can power pretty much anything, from your smartphone and tablet to laptops and portable game consoles like the Nintendo Switch. However, they're primarily aimed at portable media and communication devices.
Most power banks can charge a smartphone multiple times and have more than one output, which gives you the option to charge a number of devices simultaneously, like two smartphones or your smartphone and tablet.
Some models even pack enough grunt to power laptops, but we'd only recommend this if you're caught without access to a power point or have forgotten your laptop charger. It's handy in an emergency, but it isn't a substitute for your standard external power supply.
The main things to consider when shopping for a power bank are:
- size
- shape
- weight
- capacity
A nice clear indication of available power is also useful, with some models showing a digital display rather than bars (e.g. "80% remaining").
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Power bank capacity explained
Capacity, shown as milliamp hours (mAh), is a rough indication of the power bank's charging capabilities – the higher the number, the more power it can deliver to your device before it also runs out of juice.
Try to find a power bank 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.
A 10,000mAh power bank should recharge a smartphone up to three times, while a 20,000mAh power bank can provide more than six full charges
Power banks vary in capacity, ranging from around 3000mAh for a single charge to over 20,000mAh. Considering most modern smartphones have a battery capacity of roughly 3000mAh, a 10,000mAh power bank should recharge a smartphone up to three times, while a 20,000mAh power bank can provide more than six full charges.
Our power bank testing has found that the actual capacity rarely matches the claimed capacity, but you can calculate the number of charges you'll get by dividing the power bank's claimed capacity against your phone's stated capacity. To save you from getting caught out, take the claim on the power bank and discount that figure by 40% to make sure you're suitably covered.
Size and weight
Size and weight generally increase with mAh capacity. While a 20,000mAh power bank may seem like a handy option, it could be too big for your pocket.
If you're looking to keep your phone charged at a one-day music festival, picnic, or on 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 call for larger models, but these are usually too big for most pockets.
Shape and style
This isn't too much of an issue if you plan to carry the power bank around in a bag, but weird shapes and bulky designs may be uncomfortable for your pocket.
Certain shapes and styles can affect portability and pocketability.
Connecting your device to a power bank
Most power banks will have at least one of the below charging inputs.
USB-A: The rectangular-shaped port built into basically every hard drive and TV of the past 20 years.
Micro/mini USB: The miniature USB variant typically used in older smartphones and some portable devices is becoming less common but may still be the connection option for older power banks on sale.
USB-C: This is becoming the default USB option with the ability to simply plug into the power bank regardless of the orientation. Apple finally abandoning its proprietary Lightning connection for its iPhone 15 range will also push the USB-C format forward. USB-C should be at the top of your list of inclusions when shopping for your next power bank.
Wireless: A small number of models let you charge wirelessly by placing your smartphone on the power bank, but your phone needs to support wireless charging for this to work. There are also some models that can charge the Apple Watch, which is both specific and very handy if you happen to have one.
USB firmware running beneath the surface tells the inputs what to do, like how much data, power and speed can run through the cable. This includes 'fast charging', which is a popular feature with power banks.
Fast charging explained
In order to successfully fast-charge a device, you'll need three things:
- a compatible power bank
- a compatible cable
- a device that will accept a fast charge.
The compatible power bank is simple to confirm, as it should be on the box or unit. Support for the cable is more problematic, as even USB-C cables have different capabilities, and it's difficult to determine by looking at the cable.
Check your device's specs on the manufacturer's website to confirm whether it has fast charging. If this information isn't available, and if you're using a low-end device with entry-level components, or an older model, it's safe to assume that it doesn't have fast charging.
How long does a power bank take to charge a device?
Most power banks can charge a standard 3000mAh device, such as a smartphone, in a few hours. 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.
A few things need to match up in order for a power bank to charge your device. For starters, the power bank's output needs to meet the requirements of the device you want to charge. Smartphones can charge off a small current, tablets require more, and laptops and handheld consoles require more again.
If the output matches or exceeds the device's demands, it will charge while in use. If the output meets (or falls just short of) the device's requirements, it will slowly increase battery life, but it won't charge during use. In this instance, the power bank is 'powering' the device, not charging it. However, it will charge if the device is turned off.
Do you need USB-C?
USB-C is a standard connection that is now the default for most smart devices. Visually, it's a compact version of USB-A with rounded corners. It adds two interesting features in the context of power banks: in addition to its ability to accept the cable in any orientation, USB-C can send a charge in both directions and it also supports fast charging.
Like a USB-A fast-charge port, USB-C only works if the aforementioned circumstances line up. As this is now the most common option, you should only buy a power bank with a Lightning or micro USB connection if you specifically need it for your older device.
