The answer? A power bank. In essence another battery which you charge up in advance (very important that bit) and then use to charge / power your phone. So here's our selection of the Top 5 Power Banks available now.
As we get to see new kit, we'll be updating this page, so keep popping back to stay up-to-date with our selection.
Once upon a time, solar charging was a bit of a joke... taking literally days to charge devices - especially here in Britain. But now solar technology is starting to be a serious option for charging walkers' devices. And leading the pack is the Freeloader iSIS.
Obviously, charging times depends on the sunlight available, but the solar cell on the iSIS is upto 50% more efficient than others, and can fully charge the average smart phone 3 times at full capacity. Thanks to its' built-in charging arms, it will happily charge either Lightning or Micro USB devices, and a built-in stand allows you to angle the iSIS at the sun at all times - or you can even attach it to your backpack.
And if you have no sunlight at all, the iSIS can be charged back at base in the usual fashion by plugging it into a Mains USB charger - and will still provide charging for devices whilst out on the hill.
£64.99 - Buy Now
Powermonkey Sport 25 power pack
If you need flexibility whilst on the hill, then the Powermonkey Sport 25 is difficult to beat. The unit houses a lightweight yet powerful 6700mAh lithium-ion battery, capable of recharging a GoPro Hero5 four times and a Garmin Edge 1000 four times. It is also compatible with a plethora of other 5V devices such as smartphones, tablets (including iPad), iPods, digital cameras, sat phones and more.
£45 - Buy Now
Aukey USB-C 26500mAh Power Bank
So eagre were power experts Aukey to sell the virtues of their new 26,500mAh power bank they sent it to us for review before it was even available in the UK. It's now available here, as is the smaller capacity version too.
This is a monster of a device - whereas some other power banks are 2,000mAh - meaning they'll charge the average smartphone once - this an outstanding 26,500mAh! That's enough to charge the average phone around ten times on one charge. And because it's equipped with Quick Charge 3.0 technology, it can charge devices up to 4 times faster than normal chargers - providing you have a compatible device. But even if you haven't, it can charge all 5V USB powered devices including Android and Apple phones faster too.
26,500mAh version - £57.99 - Buy Now