This little-known smartphone has the best battery life I've ever tested

With each passing year, smartphones get thinner, faster, and stronger, with sharper cameras and better displays. But all of that eats power, and lithium-ion batteries are still flawed, needy little things.

There is no perfect way around this. Barring some major technical breakthrough, you simply cannot get a phone that lasts a week off a single charge and adequately performs all the tasks people expect from a modern smartphone.

But the Asus Zenfone 3 Zoom makes the best of what we've got today. The latest device from the Taiwanese tech firm is unremarkable from a distance - it's a midrange Android phone, and there are a million of those. However, by mixing a giant 5,000 mAh battery, an energy-efficient processor, and a good enough display, it lasts longer than any other decently-powerful smartphone I've seen.

Whether that's enough to make it worth your $330, though, is another question. Let's take a closer look: