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How we test power banks

Here's how we find a good power bank that will keep your smart device up and running when you need it most.

phone power bank chargers

Our power bank reviews help you find the best model to keep your smart device going when you're out and about. We assess their size, ease of use and charging capabilities, so you can be confident you're making the right decision when it's time to buy. Here's how we do it.

How we choose what we test

We look for readily available power banks with:

  • A power rating of at least 10,000mAh, up to around 30,000mAh, though we do test larger capacity models from time to time.
  • The ability to charge multiple devices at once.
  • The ability to charge devices other than a smartphone, such as tablet, laptop or portable games console.
  • Fast-charge capabilities.
  • RRP between $25 and $200.

We also looked for models with USB-C connectivity (though this is only available on some products).


Our overall score comprises:

  • Capacity performance (70%)
  • Ease of use (15%)
  • Display (15%)

Multiple device score is assessed if applicable, but does not contribute to the overall score.

How we test

We rate and/or assess the following aspects of each power bank:

  • Capacity performance: Each product is connected to a Maynuo M9712 DC electronic load reference instrument. This instrument is set to draw the maximum supported current from the power bank's fastest charging USB-A port. Only the current is programmed in to the instrument is determined by the power bank itself and recorded in the output. The output is sent to a PC and logged in a spreadsheet, with the data graphed to show the capacity drain over time. This test gives us the total milliamp hours that the battery supports.
  • Multiple device score: Refers to the power banks' ability to charge multiple devices at once, if more than one port is available. Higher scoring models showed a limited drop in charging performance when two or more devices were plugged in.
  • Ease of use: Based on port labelling (were the inputs clearly labelled e.g. USB-A, USB-C and fast charge) and quality of instruction manual.
  • Display: Takes into account the position of the display on the unit and how easy it is to see and understand at a glance.
  • Charge time: We completely drain a smartphone, and note the time required to charge the device to 80 percent. We run this test three times.
  • Usable capacity: We calculate what 80 percent of the battery capacity of our test phone is, then we use the power bank to charge the test phone to 80 percent, multiple times, until the power bank is fully discharged. Finally, we multiply the number of charges (including partial charges) by the 80 percent phone battery capacity value to give the usable capacity of the power bank.
  • Power bank charge time: We drain a power bank to the point where it will not charge a smartphone, then record how long it takes to recharge.
  • Powering a laptop: Some USB-C enabled power banks can power USB-C enabled laptops using a USB-C to USB-C connection. This means the laptop battery will last longer as the power bank is essentially operating as a second battery. Charging is different to powering, as it replenishes the battery during use or when it's off. Power banks in this test can't charge laptops, but some can power laptops. If the laptop didn't indicate that it was on battery power, then we determined that the power bank on test couldn't power it.
  • Powering a Nintendo Switch: This is the same as the USB-C laptop test, but with a Nintendo Switch.
  • Pocketability: Broad guide based on our experience handling the devices.
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