Ten external battery packs

Mophie Powerstation Pro

I'm not too sure why you'd need to ruggedise a portable charger as heavily as this, but with official IP65 rating, the Powerstation Pro is one hefty juice pack.

Two rubber flap-protected ports - a USB out and Micro USB in - are fiddly to access for nailbiters like myself, but you'd be thankful for that if you pulled this one out on a sandy beach. A button on the side engages a quartet of LEDs that line the top to show how much power remains.

The unit will take up most of the space in any pocket it's carried in and is a tad on the heavy side anyway for such use, so is more suited for bags.

The industrial look is awesome, but you do pay for that added protection and charging almost a hundred quid seems excessive, particularly with only a micro USB cable supplied. We found a quarter shaved off that RRP on Mobile Fun, so shop around and you can source a juicy deal.

PowerTraveller Solarmonkey Adventurer

Ah, solar chargers. I have yet to be impressed, but I do remain optimistic about the concept. The Solarmonkey Adventurer attaches neatly into its carrycase and could be the ideal companion for long trips in sunny countries, particularly if you've left your Crosskase Solar backpack behind. The water and shock resistant charger comes with a USB adaptor cable and five heads for a range of devices.

The Adventurer is said to fully recharge in 12 hours of "strong sun" thanks to its 3W solar panels. While I'd expect that to take months in most of the UK, perhaps even years in Scotland, the panels' MPPT technology, gives it more efficiency than usual in low light conditions. You can tell when it's all working: the built-in LED glows red when charging and green when at full capacity. You can replenish juice regularly through the mains or USB too.

The 2500mAh maximum capacity feels like it should be higher in a device this big, but I guess that solar tech takes up a lot of room and you obviously pay for the novelty.