Another suite of Apple iPhones, another media frenzy. Much has been written about the $999/£999 iPhone X, the demise of the home button, the “face ID” function, wireless charging and so on. Somewhere down the list of improvements was extra battery life, at least for the iPhone X, thanks to its new souped up A11 bionic processor.

Apple says the new device will charge for up to two hours more than the iPhone 7, suggesting 14 hours of internet use, for instance. Battery life on the iPhone 8, on the other hand, appears to be about comparable with its predecessor. Wireless charging, to which Apple is late to the party, makes no difference to the amount of power devices can store.

Improvements to batteries are usually a key part of smartphone launches, as you would expect for one of the major specifications on which consumers judge new devices. Samsung had much to say on this subject when it launched the Galaxy Note 8 last month – albeit less about extending battery life than ensuring no repeats of the flaws in Note 7s that made them prone to catch fire.

Yet several decades into the mobile computing revolution, even the best products are still relatively limited in how long they can function on a single charge. The original iPhone was good for eight hours of internet browsing, for example, so Apple’s devices have only advanced modestly in ten years.

So far, manufacturers have tended to focus on improving battery technology, packing more and more energy into less and less space. Those fiery Galaxy Note 7s were a cautionary tale of what can go wrong when this energy gets released as heat.

Manufacturers also look to improve other mobile hardware that consumes energy – including the display, WiFi, GPS and the central processing unit (CPU). The new iPhones’ improved CPUs and OLED screens have made them more battery friendly, for example.

But one area that has received surprisingly little attention is the energy consumed by software, or rather the energy consumed by the CPU when running particular software. Neither Samsung nor Apple seemed to make any noises in this direction with their latest launches, but this emerging field could make a major difference to how long we need to charge our devices in future.

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