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What to know before buying a power bank

Keep your mobile device battery charged, no matter where you are.

phone power bank chargers

Smartphone screens are getting larger and Australians are using their mobiles more than ever. So when you need to keep your most important device going, look to a power bank to keep you connected.

Rechargeable devices can add more juice to your smartphone's battery when you're out and about, especially if you're finding yourself with just 20% battery left by early afternoon.

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What can power banks charge?

These battery packs can power pretty much anything, from your smartphone and tablet to laptops and portable games consoles like the Nintendo Switch. However, they're primarily aimed at portable media and communication devices.

Most can charge a smartphone multiple times and a 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 recommend this only if you're caught without access to a power point or have forgotten your laptop charger. It's handy in an emergency, but 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").

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 be able to charge a smartphone up to three times and a 20,000mAh power bank more than six times

Power banks can range from single charge (3000mAh) to well over (20,000mAh), and most of the latest smartphones have a battery with around 3000mAh. A 10,000mAh power bank should be able to charge a smartphone up to three times and a 20,000mAh power bank more than six times.

Our testing has found that the actual capacity rarely matches the claimed capacity, but you can calculate 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 model may seem like a handy option, it may be too big for your pocket.

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 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. Your phone also 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 charge 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 charge. 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 charge.

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. 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 just falls short, of the device's requirements, it will slowly increase battery life, but 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 supports fast charge. 

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.


USB-C cable and input.

How much do power banks cost?

The models in our power bank reviews range in price from $15 up to $170. While you can buy power banks for under $30, these cheaper models are generally under 3000mAh, so you'll only get one charge out of them at a time (if you're lucky). Plenty of the power banks we recommend are under $100, so you don't have to spend top dollar to get a good one.

How to recycle your old power bank

Your power bank's ability to hold a charge will degrade over time, but they're easy to recycle when it's time to buy a new one. Mobile Muster is a free phone recycling service in Australia that also accepts smartphone accessories, including power banks.

Drop-off points include Optus, Telstra and Vodafone stores, as well as Officeworks, Salvos Stores and many local council offices. You can find your nearest drop-off site by entering your postcode at the Mobile Muster recycling page.

Alternatively, you can mail in your old power bank. Prepaid mailing satchels are available for free at Australia Post offices, JB Hi-Fi stores or from Mobile Muster directly. Just ask the staff and they should have them on hand. 

Australia Post provides free return labels you can print, which is a good option if you need to recycle a few items at once, but remember each package has a 15kg limit.

Stock images: Getty, unless otherwise stated.