Your buying guide for the best power banks in 2017
Phones get faster every year, but the more powerful they become the less their batteries can keep everything going. And, of course, all batteries will degrade over time. If you need extra battery power for your smartphone, tablet or other USB-powered device, you need a power bank. Also see: How to charge your smartphone or tablet faster.
You might assume all power banks are much the same thing, but you would be wrong. You can get compact power banks that will charge your phone once, slightly larger portable chargers that might offer two or three charges, or high-capacity banks that can charge your phone in excess of 10 times.
Working out how many times a power bank will charge your phone depends on more than the mAh rating on the packaging. No power bank is 100 percent energy-efficient, with every portable charger losing power through voltage conversion and heat generated.
The industry standard for energy efficiency is between 60- and 70 percent, but some of the best can offer 90 percent efficiency.
We're seeing an increasing number of power banks with support for Quick Charge 4.0 and USB-C, and in some cases these are supported on the input as well as the output, making them as fast to refill as they are to charge your phone. Power banks may offer these in place of or alongside full-size USB, Micro-USB and Lightning ports.
We're starting to see power banks that feature an AC/DC outlet (a plug socket for non-USB devices). Unfortunately many offer only a US two-pin plug, so you may need to carry an adaptor.
Another type of power bank builds in solar panels. You might think living in the UK our grey climate would rule out the use of such a device, but even in cloudy conditions these devices can draw some solar power.
Design is important when it comes to choosing a power bank, and some batteries are more compact than others at the same capacity. You can also buy those protected from the elements, but be sure to check whether they are waterproof or simply rainproof.
Nearly all power banks use LEDs to show you how much power remains in the device. This is fine for smaller-capacity devices, but when each LED represents several charges for your phone it can be difficult to see where you are. We favour banks with built-in LCDs.
Passthrough charging is a great feature to have - the ability to charge a connected smartphone at the same time as the device itself.
Auto-on and auto-off is another sought after feature, though sometimes a bank can support this and your phone won't. It means you can plug in a device and the power bank will begin charging without you pressing any buttons. When charging is complete it will put itself into standby mode to conserve energy.
Some power banks also come with an LED torch, activated by double-pressing the power button.
Get the fastest charging rates
The input rating is key when it comes to recharging the bank - the higher is this figure the more quickly it will charge. You'll see a figure in Amps, and you multiply this number by the voltage (5V for USB) to find the rating in Watts.
Don’t expect to get a USB mains charger in the box - you can use that which was supplied with your phone or tablet. Note that a power bank with a 2A (10W) input will not recharge its own battery any faster than one with a 1A (5W) input when used with an underspecified USB charger.
The reverse is also true when it comes to charging your devices - a phone that supports only a 1A (5W) input won’t charge faster from a 2A (10W) output. See also: Expert tips on how to charge your phone
The output rating refers to how quickly a power bank will charge your devices. In most cases you’ll find 1A (5W), 2A (10W) or 2.5A (12.5W) outputs.
You can use any output to charge any USB device - it will draw only the power it needs. However, you might find some tablets will refuse to charge from lower-specified outputs.
Increasingly power banks feature clever technology called PowerIQ or similar. This allows the bank to recognise the type of device you have connected and deliver the optimum amount of power.
If a power bank has several outputs the maximum total output capacity is key, since it may not be able to simultaneously support each at full power.
Best power banks 2017 UK - best power bank reviews
1. Zendure A2
- Reviewed on: 23 March 2016
It might seem strange to find a power bank at number one in our chart that doesn't have an LCD screen, doesn't support USB-C or Lightning, doesn't have multiple outputs and doesn't feature Quick Charge 3.0 support. But we stand by our claim that the Zendure A2 is absolutely the best personal power bank on the market. It's compact. It's good-looking. It's fast. It's super-tough. It's plug-and-go. It has enough capacity for several charges and it's great value. A well worthy winner of our best power bank crown.
Read our Zendure A2 review.
- Reviewed on: 13 July 2017
Fast, portable, high in capacity and affordable. There are some boxes the Anker PowerCore Speed 10000 QC power bank does not tick, yet you’d be pushed to find fault with it at £25. A recommended gadget for the upcoming festival- and holiday season.
Read our Anker PowerCore Speed 10000 QC review.
- Reviewed on: 17 January 2017
It has a similar usable capacity to the similarly priced Omnicharge, yet lacks its LCD screen and is much larger and less easily portable. However, this RavPower PowerStation Series 20,100mAh Portable Power Outlet is much easier to get hold of in the UK and even comes with a UK three-pin AC outlet. Both devices are expensive at around £100, but offer insanely fast charging (and recharging) of almost anything you like. A fantastic buy if you can afford it.
- Reviewed on: 6 July 2016
CHJGD is doing what it can to bring some colour to the functional-looking power bank market with the bulldog-inspired UltraCompact Power Bank. It has useful capacity, and it is affordable and easily portable. A great buy if you're in the market for a portable charger you can slip into a pocket.
Read our CHJGD UltraCompact Power Bank review.
- Reviewed on: 4 July 2017
Moshi has created one of the most attractive and portable power banks we’ve seen in the IonSlim 5K - this is one of the few that you really won’t mind carrying around with you. Our only real gripe is the price: £50 is a lot for a 5,150mAh battery, so you’ve got to decide how much of a premium you’re willing to pay for the pared down design.
Read our Moshi IonSlim 5K review.
6. Zendure A3
- Reviewed on: 30 November 2016
Higher in capacity than the class-leading Zendure A2, but with the same indestructable design and an extra USB output, the Zendure A3 is a great choice if you want a little more pocketable power for charging your phone and/or tablet away from home. If you need more power still check out the £40 Zendure A4, which is otherwise identical to this Zendure A3.
Read our Zendure A3 review.
- Reviewed on: 25 January 2017
A good-looking, mid-capacity rugged power bank that will fit neatly into the pockets of campers, hikers and other outdoorsie-types. It's a shame that the DXPower Armor is waterproof only when it's not in use, but this is a criticism we could level at most - if not all - 'waterproof' power banks.
Read our DXPower Armor DX0001 review.
8. Flux Card
- Reviewed on: 18 August 2016
A fantastic upgrade over the original Flux Charger, the new 4,000mAh Flux takes onboard all our criticisms and comes back fighting. An excellent, truly portable power bank that will get any smartphone user out of a jam. If you need more capacity, also see the 10,000mAh Flux Charger Plus, now with two additional full-size USB outputs.
Read our Flux Card review.
- Reviewed on: 21 July 2017
A smaller version of the recommended Magnum Opus, the Opus Mini is a better fit for your pocket and for your wallet. The LCD screen is a very useful inclusion.Our only real criticism concerns the lack of passthrough charging.
Read our CHJGD Magnum Opus Mini review.
- Reviewed on: 24 July 2017
It’s expensive, but this Anker heavyweight is an excellent power bank for topping up anything and everything with a USB port - and doing so several times. It is quick to recharge, provided you have a PD adaptor, and will keep on going and going. A great buy if you can afford it.
Read our Anker PowerCore+ 26800 PD review.