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Best power banks and portable chargers 2024: Which? Best Buys and expert buying advice

We've tested power banks from Anker, Belkin, INIU and more, to help you find the perfect portable charger to top up your devices on the go
Jonny MartinResearcher & writer
Two women use power bank charger

Power banks are big rechargeable batteries with built-in USB ports, and their flexibility and portability make them one of the most useful accessories you can carry for keeping your devices topped up.

We've tested more than 100 power banks over the years from brands including Anker, Samsung, Belkin and INIU, assessing how easy they are to use, their features and charging times.

We've split our reviews between small, medium, and large power banks, with Best Buy recommendations in each category. Some of the best power banks can charge your smartphone in under 70 minutes. The most sluggish can take almost three and a half hours. 

The best large power banks from our tests

The largest power banks we've tested come with four times the capacity of the smallest ones – enough to charge your phone up to five times – though they are often four times the size and weight.

Only logged-in Which? members can view the power bank test results below. 

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Power bankTest scoreNumber of device chargesPower bank charging timeDevice charging time Where to buy 
84%4.63 hours 9 minutes1 hour 14 minutes
80%56 hours 10 minutes1 hour 42 minutes
75%3.43 hours 46 minutes2 hours 3 minutes
74%4.66 hours 42 minutes1 hour 44 minutes
74%4.25 hours 31 minutes2 hours 26 minutes
69%3.25 hours 17 minutes1 hour 46 minutes
67%4.35 hours 28 minutes1 hour 25 minutes

Dates tested: June 2024, March 2024, June 2023, December 2022, August 2022, September 2021, April 2021. Page last checked: July 2024. We are not able to show every retailer and cheaper prices may be available. 'Number of device charges' and 'Device charging time' are based on charge performance with the selected power bank and a Samsung Galaxy S20 5G smartphone (which has a 4,000mAh capacity battery). 


After something smaller? Check out the best small power banks or the best medium power banks.


The large power banks we tested

All the large power banks we tested are listed in alphabetical order below. 

Only logged-in Which? members can view the best power banks from our tests.

Join Which? to get instant access to our test results and Best Buy recommendations below.

Anker 335 Power Bank PowerCore 20K

Anker 335 PowerCore

Pros Log in or join Which? to instantly reveal

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Most recently tested June 2023

Size and weight 2.5 x 8.4 x 16.5cm (HxWxL); 484g

Capacity 20,000mAh

Need to know Power delivery fast charging, USB-C input/output, 2 USB-A outputs

Einova Laptop Power Bank Ultra Fast (63W)

Einova Laptop power bank ultra fast

Pros Log in or join Which? to instantly reveal

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Most recently tested June 2024

Size and weight 10 x 1.6 x 17.5cm (HxWxL); 450g

Capacity 20,000mAh

Need to know Power delivery fast charging, USB-C input/output, 2 USB-A outputs

Energizer Ultimate 20000mAh Portable Power Bank UE20011PQ

Energizer Ultra power bank

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Most recently tested June 2023

Size and weight 2.9 x 6.9 x 14cm (HxWxL); 405g

Capacity 20,000mAh

Need to know Micro-USB input, USB-C input/output, 2 USB-A outputs

INIU Power Bank 22.5W Fast Charging 20000mAh

Iniu power bank 20000mAh

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Size and weight 2.7 x 7 x 13.5cm (HxWxL); 342g

Capacity 20,000mAh

Need to know Power delivery fast charging, USB-C input/output, 2 USB-A outputs

Juice ECO 5 Charge Power Bank 15000mAh 

Juice ECO 5 charge power bank

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Most recently tested December 2022

Size and weight 2.7 x 6.8 x 14cm (HxWxL); 362g

Capacity 15,000mAh

Need to know Micro-USB input, USB-C input/output, 2 USB-A outputs

Juice ECO Max 7 Charge Power Bank 20000mAh

Juice ECO Max 7 charge power bank

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Most recently tested December 2022

Size and weight 2.7 x 6.8 x 14cm (HxWxL); 402g

Capacity 20,000mAh

Need to know Micro-USB input, USB-C input/output, 2 USB-A outputs

Otterbox Wireless, 15000mAh

Otterbox 15000mAh wireless power bank

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Most recently tested June 2024

Size and weight 7.3 x 2.5 x 14.6cm (HxWxL); 347g

Capacity 15,000mAh

Need to know Wireless charging, Power delivery fast charging, USB-C input/output, USB-A output


In the market for a new smartphone with better battery life and new features? See our pick of the best smartphones at different price points.


 The best medium power banks from our tests

Medium power banks represent a nice balance between portability and capacity. They're about the same weight as a paperback book, can fit into a large pocket, and have enough capacity to charge a smartphone twice.

Only logged-in Which? members can view the power bank test results below. 

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Power bankTest scoreNumber of device chargesPower bank charging timeDevice charging time Where to buy 
86%2.32 hours 8 minutes1 hour 32 minutes
82%2.12 hours 43 minutes1 hour 8 minutes
77%2.32 hours 57 minutes1 hour 45 minutes
75%2.22 hours 41 minutes1 hour 24 minutes
75%22 hours 56 minutes1 hour 48 minutes
66%2.45 hours 4 minutes3 hours 27 minutes
44%1.75 hours 29 minutes3 hours 2 minutes

Dates tested: June 2024, March 2024, June 2023, December 2022, August 2022, September 2021, April 2021. Page last checked: July 2024. We are not able to show every retailer and cheaper prices may be available. 'Number of device charges' and 'Device charging time' are based on charge performance with the selected power bank and a Samsung Galaxy S20 5G smartphone (which has a 4,000mAh capacity battery). 


Fancy a few more charges to make sure your device lasts your entire trip? Then check out the best large power banks. Alternatively, if you’re after something even more portable, head to the best small power banks.


The medium power banks we tested

All the medium power banks we tested are listed in alphabetical order below. 

Only logged-in Which? members can view the best power banks from our tests.

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Belkin Boost Charge USB-C PD Power Bank 10K

Belkin Boost Charge 10k power bank

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Most recently tested September 2021

Size and weight 1.7 x 7.5 x 14.3cm (HxWxL); 247g

Capacity 10,000mAh

Need to know Power delivery fast charging, USB-C input/output, USB-A output

Charmast 10400mAh Power Bank

Charmast 10400mAh power bank

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Most recently tested June 2023

Size and weight 1.5 x 6.7 x 14.4cm (HxWxL); 221g

Capacity 10,400mAh

Need to know Micro-USB input, USB-C input/output, 2 USB-A outputs

Duracell Charge 10 Power Bank

Duracell Charge 10 power bank

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Most recently tested March 2024

Size and weight 1.6 x 7.4 x 14.3cm (HxWxL); 247g

Capacity 10,000mAh

Need to know Power delivery fast charging, USB-C input/output, USB-A output

Duracell Core10 PD 25W Power Bank

Duracell Core10 PD power bank

Available from Duracell (£29.99)

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Most recently tested June 2024

Size and weight 7.5 x 1.6 x 16cm (HxWxL); 252g

Capacity 10,000mAh

Need to know Wireless charging, Power delivery fast charging, USB-C input/output, USB-A output

Energizer Max 10000mAh UE10058

Energizer Max 10000mAh power bank

Pros Log in or join Which? to instantly reveal

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Most recently tested August 2022

Size and weight 1.7 x 7 x 14.6cm (HxWxL); 225g

Capacity 10,000mAh

Need to know Micro-USB input, USB-C input, 2 USB-A outputs

INIU BI-B6 10000mAh Portable Charger

Iniu BI-B6 10000mAh power bank

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Most recently tested March 2024

Size and weight 1.5 x 7 x 13.5cm (HxWxL); 205g

Capacity 10,000mAh

Need to know Power delivery fast charging, USB-C input/output, 2 USB-A outputs

Samsung 25W Wireless Battery Pack

Samsung 10000mAh wireless power bank

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Most recently tested June 2024

Size and weight 7 x 1.5 x 14.8cm (HxWxL)211g

Capacity 10,000mAh

Need to know Wireless charging, Power delivery fast charging, 2 USB-C inputs/outputs


Our best tablets guide highlights the models that are perfect for on-the-go productivity and entertainment, providing a middle ground between a smartphone's portability and a laptop's functionality.


 The best small power banks from our tests

Smaller power banks tend to weigh around 115g, are approximately the same size as a deck of playing cards, and will charge the average smartphone from flat to full just once before needing to be charged themselves.

Only logged-in Which? members can view the power bank test results below. 

Join Which? to get instant access to our test results and Best Buy recommendations below.

Power bankTest scoreNumber of device chargesPower bank charging timeDevice charging time Where to buy 
78%0.92 hours 29 minutes
72%12 hours 43 minutes
66%1.13 hours
64%12 hours 31 minutes
64%1.14 hours 28 minutes
58%13 hours 29 minutes
79%1.33 hours 23 minutes

Dates tested: June 2024, March 2024, June 2023, December 2022, August 2022, September 2021, April 2021. Page last checked: July 2024. We are not able to show every retailer and cheaper prices may be available. 'Number of device charges' and 'Device charging time' are based on charge performance with the selected power bank and a Samsung Galaxy S20 5G smartphone (which has a 4,000mAh capacity battery). Not every small power bank in the table can deliver a full charge to this smartphone, so we have used star ratings rather than times for the 'Device charging time' column. 


After something that can deliver more charges to your devices before needing charging itself? Check out the best medium power banks or the best large power banks.


The small power banks we tested

All the small power banks we tested are listed in alphabetical order below. 

Only logged-in Which? members can view the best power banks from our tests.

Join Which? to get instant access to our test results and Best Buy recommendations below.

Anker 321 Power Bank PowerCore 5K

Anker 321 PowerCore power bank

Pros Log in or join Which? to instantly reveal

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Most recently tested December 2022

Size and weight 2.2 x 4.5 x 9.7cm (HxWxL); 130g

Capacity 5,200mAh

Need to know USB-C input/output, USB-A output

Anker Nano Power Bank

Anker Nano power bank

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Most recently tested June 2024

Size and weight 3.7 x 2.5 x 7.7cm (HxWxL); 101g

Capacity 5,000mAh

Need to know Power delivery fast charging, 2 USB-C inputs/outputs

Anker PowerCore 5000

Anker PowerCore 5000 power bank

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Most recently tested April 2021

Size and weight 10.7 x 3.2 x 3.2cm (HxWxL); 132g

Capacity 5,000mAh

Need to know Micro USB input, USB-A output

Groov-e Power Stick CH5000 

Groov-e Power Stick

Pros Log in or join Which? to instantly reveal

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Most recently tested August 2022

Size and weight 1.4 x 6.3 x 9.3cm (HxWxL); 109g

Capacity 5,000mAh

Need to know Micro-USB input, USB-C input/output, USB-A output

Hama Slim 5HD Power Pack 5000mAh

Hama Slim 5HD Power Pack

Available from Amazon (£12.99) and Ryman (£16.99)

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Most recently tested August 2022

Size and weight 1.4 x 6.5 x 9.2cm (HxWxL); 109g

Capacity 5,000mAh

Need to know Micro-USB input, USB-A output

Juice ECO 2 Power Bank 5000mAh

Juice ECO 2 power bank

Pros Log in or join Which? to instantly reveal

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Most recently tested June 2023

Size and weight 1.4 x 6.4 x 9.3cm (HxWxL); 110g

Capacity 5,000mAh

Need to know Micro-USB input, USB-C input/output, 2 USB-A outputs

Mophie Powerstation 5000mAh (fabric)

Mophie Powerstation Fabric 5000mAh

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Most recently tested April 2021

Size and weight 1.1 x 6.9 x 13cm (HxWxL); 127g

Capacity 5,000mAh

Need to know USB-C input/output, USB-A output


Ebook readers can store thousands of books and magazines, so you'll never run out of reading material while out and about. See our roundup of the best ebook readers to find the best models available now. 


How we test power banks

To date, we've tested more than 100 portable power bank chargers. The most popular and relevant models are shown on this page. Our rigorous testing programme involves:

  • Number of device charges We've often found that devices with the same claimed capacity supply different amounts of energy in real-world conditions; some are much less efficient as they lose lots of energy through heat. We test each power bank on real devices – a Samsung Galaxy S20 5G smartphone, which has a 4000 mAh battery capacity, and a Samsung Galaxy Tab S6 tablet, with a 7040 mAh battery capacity – to see how much charge you'll actually get. 
  • Power bank charging time We record how long it takes for the power bank to go from 0% battery to fully charged when plugged into a standard wall socket.  
  • Device charging time We record how long it takes for the power bank to fully charge a Samsung Galaxy S20 5G phone.  
  • Features This includes the number of outputs and inputs a power bank has.
  • Ease of use We assess the portability of the power banks, how well spaced and well labelled the ports are, and how readable their battery power level indicators are. 

We regularly revisit the power banks and portable chargers on sale to see if there are any more popular models that need testing and when we find them we do.


Find out more about how Which? is not influenced by product manufacturers or retailers and how your support helps us to stay editorially independent.


What capacity power bank should you choose?

Small power banks can be great for an occasional top up of power on the go – they’re light enough that you’ll hardly feel the weight of them in your bag. Large models give you more juice but are less portable.

  • Small power banks (up to 7,500mAh) – usually enough to charge a smartphone once
  • Medium power banks (7,500-14,999mAh) – usually enough to charge a smartphone two times
  • Large power banks (more than 15,000mAh) – usually enough to charge a smartphone 4 or more times

All of the power banks shown here are intended for charging smartphones and tablets, but only the Einova Laptop Power Bank Ultra Fast has enough wattage to safely top up a laptop while you're out and about. If you try to use a power bank with lower wattage than the laptop's energy demands, the laptop might not get a steady and strong enough flow of power, which causes strain on its battery and leads to damage over time. 

Are power banks safe? 

As with all batteries, try to keep your power bank at room temperature and keep it away from direct sunlight over a long period of time. Don’t overcharge it as this can make it overheat.

A common question people ask is 'Can you take a power bank on a plane?', and yes, for the most part, you can – as long as you keep it in your carry-on baggage and the power bank doesn't exceed 27,000mAh. 

You may be asked for detailed information on the power bank. This is usually printed on the device, but it can rub off with frequent use. If it’s close to the limit and you can’t prove it’s under 100Wh, be prepared for it to be confiscated.

Power banks are not allowed in checked baggage because lithium-ion batteries, which are commonly used in power banks, can pose a fire risk if they are damaged or experience a short circuit. While this is incredibly unlikely, ensuring they are stored safely and avoiding excessive physical stress or exposure to extreme temperatures will minimise any potential hazards associated with their use.