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SunnyBag SmartBattery is a solar-powered battery for your phone

Smartphone battery life is one of the great technological bugbears of our age. This can help.

It’s called the SunnyBag SmartBattery, and it’s a solar-powered power bank for your smartphone. Hook it up to a solar panel – on a backpack, say – and it’ll suck up the sun’s rays and store the energy. Or if needs must, you can also juice it up from the wall socket.

Once fully charged, it claims to charge between four and six smartphones. Though by our reckoning, its 10,000mAh battery will more likely charge around three handsets (considering battery sizes are usually around 3,000mAh).

Using the app, you can see how much green energy you’ve produced, and share it on social media. Though you might seem a bit smug. It also shows you how much energy you’ve used, and how much juice is left in the bank.

It has some other abilities too. It can act as a remote shutter button, so you can position your phone somewhere and snap a selfie. And it sends you an alert if you veer more than 10m away from it, so you’ll never lose it.

It has two USB ports, so you can charge two devices at once. And the app works on iOS and Android.

Read more: Solar Paper claims to be the world’s thinnest and lightest solar charger

And if you don’t have a solar-panelled bag? It’s okay, the firm makes a range of them too.

It’s passed its €10,000 goal and will ship in May 2016. Prices start at £43.

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