Power Banks Guide: How to Keep Connected with Portable Power

Power banks are a modern lifesaver and come in all sorts of configurations, so it’s vital to match the right model to your power-hungry needs.

A red battery icon can be cause for consternation in what has become an increasingly connected world, however for those of us consistently caught short and seeking to stave off battery drain, a power bank could provide a simple and effective stopgap.

Battery life anxiety is a byproduct of the mobile age, with an LG survey conducted a few years ago revealing nearly nine out of 10 respondents “felt panic” upon their smartphone battery level dipping to below 20%.

Meanwhile, devices (smartphones, in particular) are becoming both increasingly powerful and power-hungry, and battery drain has become an ever-present issue.

Adding a power bank to your cadre of devices may well help to address power concerns, however there are number of factors to keep in mind when shopping around for a suitable model.

What is a power bank?

A power bank is essentially a portable charger, designed for the specific purpose of storing electricity, allowing users to charge battery-powered devices when they do not have ready access to a mains power outlet.

Power banks can be used to charge a range of USB-powered devices, from smartphones and tablets, to portable speakers, wireless headphones and cameras, while some larger models are specifically designed for use with laptops.

The power bank itself houses a battery, and will need to be periodically charged according to its battery capacity and frequency of use. Users just plug their power bank into their mains supply at home (check out Canstar’s electricity providers comparison table below), top it up and then keep it on hand for use as needed.

Power bank shopping: what to look for

There are a range of factors to keep in mind when shopping for a power bank, and you will need to consider the features on offer from different models, and the specific requirements of the devices you are seeking to charge.

If you’re seeking to charge multiple devices, flexibility will likely be an important consideration, and it’s worthwhile weighing up models that incorporate a variety of features.


As is the case with most battery-powered devices, power banks typically employ the mAh (milliampere hour) measurement of battery capacity, with a greater mAh capacity meaning a power bank will be able to deliver more power over time.

Power banks are commonly available with capacities ranging from 2,600 mAh through to 15,000 mAh, with some larger models equipped with in excess of 20,000 mAh.

To put this into perspective, many new mid-range and budget smartphones have a capacity of around 3,500 mAh, meaning the following power bank capacities could on paper theoretically provide:

  • 5,000 mAh – a bit over one full recharge.
  • 10,000 mAh – a bit under three full recharges.
  • 15,000 mAh – a bit over four full recharges.

However, it’s also important to factor in power loss when it comes to real-world performance, and it’s often suggested a two-thirds of advertised capacity rule be applied to power banks.

A power bank with a capacity of 5,000 mAh may well be suitable for charging your smartphone while on the go, while greater capacity should be a priority for devices with larger batteries (such as tablets), or when seeking to charge multiple devices.

Two Power Banks

Charging options

The type of charging outputs a power bank is equipped with will determine compatibility with the devices you are seeking to charge.

Power banks equipped with multiple outputs can allow for simultaneous charging of a number of different devices, with outputs including:

  • USB-A – most power banks are equipped with a USB-A port, providing for charging compatibility with a wide range of devices.
  • USB-C – many power banks are now also equipped with a USB-C port, providing for further charging options, and allowing for faster charging.
  • Wireless charging – a number of new power banks are arriving to market decked out with wireless charging pads.
  • AC and DC – some power banks equipped with greater battery capacities, designed for use with larger devices such as laptops, sport an AC and DC outlet.

Charging speed will depend upon a variety of factors, from the rate at which a power bank can deliver charge through to the cable being used and the capabilities of the device being charged.

If speed is a priority, it’s worthwhile looking at power bank models that incorporate fast-charging technologies, however it’s first important to ensure compatibility with the device you are seeking to charge.

Charging the power bank

Power banks typically sport a micro-USB input for charging (the same sort commonly used for smartphones and other USB-powered devices), allowing for use with a standard USB wall charger, while some models provide for USB-C charging.

The amount of time it takes to charge will depend upon a variety of factors, including the power bank’s battery capacity, its charging input capabilities, the output of the wall charger and the cable being used.

Meanwhile, it’s also worth noting that there are a number of power banks available that incorporate solar charging technologies, which allow for both standard USB charging and solar charging when required.

Power banks charger

The cheapest way to charge

No matter what size power bank you purchase, it pays to charge it with the cheapest electricity. To help you find the best value electricity retailer, Canstar rates NZ power companies for customer satisfaction and value for money, see the table below for some of the results:

Canstar Blue’s latest review of NZ power companies compares them on customer satisfaction. The table below is an abridged version of our full results, available here.

See Our Ratings Methodology


Power banks come in all sorts of shapes and sizes, with plenty of design options available, and portability should be a consideration (for instance, it may be possible to slip some models in your pocket, while a backpack or laptop bag may be required for others).

Power banks sporting a lower battery capacity are typically available in a smaller, lighter form, with many of these models sporting a sleek, smartphone-style design, while a higher battery capacity will typically equate to a bulkier design.

Another feature worthwhile considering is how a power bank displays its battery status: many models employ an LED indicator, while others incorporate a digital display, providing more precise information about battery levels.


There are a great range of power banks available at different price points, from budget models with minimal features, to more expensive models sporting an array of features, with prices ranging from under $20 to over $200.

As always, it’s worthwhile weighing up your budget and requirements, and comparing the prices on offer from different electronics retailers – and that includes the cost of the electricity you’re using to charge your power bank.

If you’re regularly shocked by the size of your monthly power bill, it may be time for you to consider switching providers for a better deal. If so, you can check out and compare different electricity providers free with Canstar, just click on the button below:

Compare electricity providers for free with Canstar!

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