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Best portable power bank chargers for 2018

By Paul Lester

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A power bank can be a lifesaver in a tight spot – find out which portable chargers come closest to delivering the battery power they promise.

For all the recent advances in mobile phones, there’s one area that manufacturers have yet been unable to solve. Even the most impressive smartphones struggle to last more than a couple of days without charging under moderate use, and battery technology is fighting a never-ending battle against the latest and greatest power-draining features.

It’s no surprise, then, that power banks – or portable phone chargers – have become one of the most popular must-have accessories for smartphones. Available in all shapes and sizes, they vary from ultra-portable chargers designed to offer a quick boost, to large and arguably cumbersome alternatives that claim to fully charge a handset multiple times.

If you've used a power bank before you might agree that what’s promised on the box – often one or more ‘full-phone’ charges – is actually quite far from the truth. We decided to put this to the test, and have collected a range of power banks from some of the most popular brands to find out if they really deliver what they promise.

Batteries don’t last forever – if your smartphone has given up the ghost, check out our Best Buy smartphones for a great range of top-rated mobile phones.

How to choose the best portable charger

Before buying a portable charger, it's important to know what to look for.

Battery capacity is measured in milliamp hours – or mAh. The larger the number, the more charge a battery can (supposedly) hold. Like mobile phone batteries, power banks are measured in mAh, so you’d be forgiven for thinking that if you have a power bank that’s the same capacity as your phone battery, it’d give it a full charge. In practice, we found this to be far from clear cut.

In our results tables below, we’ve split the power banks we trialled into three categories. Low capacity (less than 5,000mAh), medium capacity (between 5,000 and 9,999mAh) and high-capacity (more than 10,000mAh).

By charging a series of mobile phones, we worked out the percentage of charge that each power bank delivered against its claim – obviously, the higher this is, the better. This percentage should only be taken as an approximation of the charge available in a power bank – additional factors mean this could vary based on the make and model of phone, and how it's charged, but it is a useful comparable measure.

Read on to find out more about each type and which performed best. We've also highlighted our top pick in each category, which may not always be the power bank that delivered the highest percentage charge.

Give yourself a head start by picking a smartphone that performs with our guide to mobile phones with the best battery life.

Low-capacity power banks

Low-capacity power banks can be ideal emergency options - especially if you want something small enough to carry around in a pocket or bag. You’ll often miss out on some useful additional features with smaller power banks – such as multiple USB ports to charge more than one device at a time, and multiple LED indicator lights, which can be useful to tell at a glance how much power is left.

Low-capacity power banks also tend to be pretty cheap, so it won't cost much to have one of these safely tucked away, ready for an emergency situation.

Browse the table below to see how a range of low capacity power banks compared.

Low-capacity power banks (<5,000mAh)
Image Price Claimed mAh % amount delivered
£13 2,500 82%

With a tidy, compact design, this power bank will slip neatly into a pocket or bag. The LED lighting is of limited use however, and it's fairly basic in operation. When it comes to living up to its claims, it achieved an impressive 82% of its promised power, making it one of the highest rated on test. 

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£14 2,500 86%

Some may not appreciate the design of this power pack. It feels solid in the hand, but the built-in LED indicators were woefully inaccurate. Fortunately, it aces the most important criteria, providing 86% of the power it claims. 

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£25 3,000 69%

This power bank is larger than you might expect for its stated capacity, and may not be portable enough for those shopping in this range. It also feels less sturdy than some alternatives, so might not take too well to being dropped. Although its LED indicator lights were pretty accurate, it only managed to provide 69% of the power it claims, which was the worst in this low-capacity category.

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£25 4,000 72%

Notably more versatile than some other power banks, this model manages to be relatively compact and offers a decent array of features. It's not the best when it comes to delivering on its promised capacity, however, achieving just 72% - the second lowest in this category. 

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£25 4,000 75%

Not everyone will appreciate the design of this power pack – although it is pretty slimline, it's a little on the large side. It offers a couple of handy features that make it unique among the devices we looked at, and could be of great benefit in the right situation. At 75% of what it claims, it's a fair performer as well, although some way from the best in this category. 

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Medium-capacity power banks

If you'll be away from a power source for a longer period of time, are planning fairly extended use of your phone or want a few added extras such as multiple device charging, some medium-capacity power banks can tick the boxes. The advantage here is that you’re getting more features and (in theory) more power, with a device that's still fairly portable and easy to carry around.

Medium-capacity power banks can still be picked up fairly cheaply and, in some cases, for a lower price than low-capacity models.

Browse the table below to see how a range of medium capacity power banks compared. 

Medium-capacity power banks (5,000-9,999mAh)
Image Price Claimed mAh % amount delivered
£20 6,700 67%

This is a power bank that's hard not to be impressed by despite the fact that it only manages to deliver 67% of the power it claims to have – actually ranking bottom in our medium-capacity power banks category. There are some pretty good reasons why, including the fact that it feels solidly built, is very portable and overall, good value for money.

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£13 5,000 74%

This power bank feels nice in the hand and looks pretty smart as well. Accurate LED lighting gives a good indication of both current charge status and how much is left. It delivered a respectable 74% of its claimed charge, which together with its compact design makes it an impressive mid-range offering.

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£12 5,200 71%

As a light and portable solution this medium-capacity power bank is fairly impressive. Although it only offers one USB port for charging a single device at a time, indicator LEDs give a reasonably accurate account of how much power is left. It delivered 71% of the promised charge, which isn't bad considering its diminutive size. This could be one to look out for if portability is a key requirement.

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£20 5,600 68%

It's impressive to see a medium-capacity power bank with such a compact design, but there are some key features missing here that may put off some users. It's not particularly capable of delivering on its stated charge either, achieving just 68% - among the worst in this category.

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£64 6,000 81%

The unusual design may not be to everyone's taste, but it does offer quite a wide range of features for a power bank. Delivering 81% of its charge this is comfortably the best in the medium-capacity category. But is this enough to make up for its deficiencies?

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High-capacity power banks

If you're looking for a charging solution that will get you through an extended period without a regular power source, or perhaps want a single product to share amongst the whole family, a high capacity power bank could do the job. These models are commonly available with capacities in excess of 10,000mAh, which on paper at least, should mean they're capable of fully charging many smartphones over three times.

The main downside of these models is size – they can be quite large and heavy, so aren’t really suitable for pockets or carrying around comfortably if you’re looking to travel light. You’ll often find dual USB ports, though, which means you can charge two devices at once, and multiple LED indicators are particularly useful here – providing they're accurate.

Browse the table below to see how a range of large-capacity power banks compared. 

High-capacity power banks (>10,000 mAh)
Image Price Claimed mAh % amount delivered
£20 10,000 76%

This is possibly the nicest design of the high-capacity power banks, taking a no-frills approach that still includes the most important features. It feels solid and well built, charges relatively quickly and also comes closest to delivering on its promise, with an impressive 76% score. An overall winner if you're looking for a high-capacity solution.

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£18 10,400 67%

The plastic finish on this power bank means it doesn't feel overly premium, although it's a little more portable than some others in this category. It includes all the essential features for a high-capacity model, but delivers an unimpressive 67% of its claimed power, making it a distinctly middle-of-the-road option.

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£23 10,400 71%

Not everyone will be a fan of the design of this power bank, but fortunately it ticks some important boxes that make it a worthy consideration. It's the second highest in the high-capacity category in terms of delivering the power it promises at 71%, so it performs as well. If you can put up with the drawbacks, this could be your best option.

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£30 11,200 54%

This power bank is deceptively large, but its solid, weighty feel gives the impression it will deliver on its claims. This wasn't the case, however, as it only achieved 54% of its purported power capacity. We had other issues with operation that mean we definitely wouldn't recommend it.

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Which power bank is best for you?

While the pros and cons of different makes and models of power bank do vary, overall the results of our first looks showed a very clear trend. We found certain categories of power banks to be, on average, significantly less able to deliver on their promised capacity than others.

The difference between specific models can vary even more dramatically. The best on test delivered 86% of its stated charge, whereas the worst was just 54%.

Another point worth noting is the time taken to charge. This varied considerably, with the longest taking up to eight-and-a-half hours, so you really need to plan in advance.

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