Phones get faster every year, but battery life doesn’t seem to get any better. If you need to keep your smartphone – or tablet or other USB-powered device – going all day, you need apower bank. We’ve rounded up the 20 best portable chargers available in the UK in 2015. Also see: How to charge your smartphone or tablet faster
Update 5 August: EE is recalling some of its free Power Bars which may be a fire safety risk. Here’s how to check whether your EE Power Bar is a fire safety risk.
Power banks come in all shapes, weights and capacities, from emergency credit-card-sized devices such as the Onaji Pawa that offers a quick boost to keep you going until you get home, to the ultra-high-capacity LimeFuel Blast Pro L240X, which might charge your phone in excess of 10 times – ideal if you’re going camping or have several devices to charge. Then there are those able to recharge their own battery using solar power, which could mean you never need charge your devices using mains power again. That could save you a few quid on the electricity bill – if you have the patience.
Best power banks 2015 UK: Choosing a power bank
Several factors are important when choosing a power bank. One is portability: some of the power banks we review are small and light enough to slip into a pocket; others you’ll notice their presence even when slung in a bag. Pay particular attention to their weight and avoid bulky designs if this is a device you’ll carry every day, rather than in certain situations only.
Another factor is capacity. It’s important to note that a power bank will not deliver its full advertised capacity to your device – some of this energy is lost through heat generated and voltage conversion. If a power bank manufacturer doesn’t expressly state otherwise, expect to achieve around 70 percent efficiency. A 10000mAh power bank might therefore deliver 7000mAh of power. Some of the best power banks offer around 90 percent efficiency. Check the specification of your phone or tablet’s battery to estimate how many full charges you can expect from this.
Best power banks 2015 UK: Charging and recharging
The input rating is key when it comes to recharging the power bank – the higher is this figure the more quickly it will charge. You’ll usually see a figure in Amps, for instance 1A. You multiply this number by the voltage (5V for USB) to find the rating in Watts. A 1A input can charge at 5W, therefore, but you’d do better to look for a device that can charge at 2A (10W).
Don’t expect to get a USB charger in the box – you can use that which was supplied with your phone or tablet. Do note, however, 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
Some power banks support a feature known as passthrough charging, but expect to pay more for this luxury. This allows them to function as a USB hub of sorts, meaning you can simultaneously charge both the power bank itself and your mobile devices, and ensures the power bank is always topped up and ready to go when you need it. You definitely don’t want to be getting up in the middle of the night to unplug your now-charged phone in order to fill up a power bank. (If you have only one mains adaptor, consider getting a desktop charger that can simultaneously charge five or six USB devices from a single mains outlet.)
The output rating refers to how quickly a power bank will charge your devices. In most cases you’ll find 1A (5W), 2A (10W) and often even 2.5A (12.5W) outputs, the former intended for smartphones and the latter two for tablets or for fast-charging phones that support the feature. (This is not the same as the quick charging feature supported by newer phones such as the Samsung Galaxy S6.) You can use either output to charge any USB device – it will draw only the power it needs. However, you might find some tablets – usually iPads – will refuse to charge from lower-specified outputs.
Increasingly power banks feature clever technology which is often referred to as PowerIQ or similar. This allows the power bank to recognise the type of device you have connected for charging and deliver the optimum amount of power for that device.
If a power bank has several outputs then the maximum total output capacity is key. For example, the LimeFuel Blast Pro L240X has four 2.4A (12W) outputs, but delivers only 4.2A (21W) total output. With four USB devices attached you will find that each charges much more slowly.
Best power banks 2015 UK: Additional features
The best power banks support auto-on and -off functionality, although some support auto-on only and others neither. Auto-on allows them to begin charging your device as soon as you plug it in, and auto-off causes them to switch off when them to switch off when the job is done, meaning no power is unnecessarily wasted. Those that don’t support this functionality will have a small power button on their casing somewhere, which is typically also used to light up the LED flashlight (if the power bank has one) or see how much capacity remains.
In most cases you’ll find a series of LEDs used to denote how much capacity remains. This is fine with smaller-capacity power banks, but with larger-capacity models you’ll find the massive jump in capacity between each LED leaves the system rather meaningless. Look out for power banks with LCD displays that are able to tell you the exact capacity remaining, so you’ll never get caught short.
A very common feature in power banks is a built-in LED flashlight. This could come in useful on camping trips, for example, but keep in mind that unless the device is reasonably portable and has an ergonomic design you’re unlikely to use it as a torch. EC Tech’s 6000– and18000mAh power banks are perhaps the best examples here: the smaller-capacity device looks and feels just like a flashlight; the latter is big, heavy and rectangular, making it a bizarre device to use as a torch.
The ideal power bank carefully balances useful capacity with portability, value, fast charging/recharging, multiple outputs and high-end features such as passthrough charging and LCD displays. The closest we’ve found in this regard is the Zendure A2, but we highly recommend all of the devices in this round-up, so you may find one better suited to your budget or one with a design you prefer.