iPhone 6s and 6s Plus battery capacity will be weaker than predecessors, Apple leaks suggest

Smaller capacity might be made up by more efficient components and new software

Store attendants help customers at an Apple store selling the iPhone 6 in Beijing on October 23, 2014 (GREG BAKER/AFP/Getty Images)

The new iPhones are likely to have batteries that pack in less power than the existing ones, according to new leaks.

The iPhone 6s will pack in a 1715 mAh battery, rather than the 1810 mAh one found in the iPhone 6, a 5.5 per cent drop in capacity. The iPhone 6s Plus will see a similar drop in size, falling to 2750 mAh, according to Chinese website cnBeta.

Battery concerns are frequently ranked among the highest complaints that smartphone owners have about their handsets, most of which tend to need charging at least once a day.

It is unclear why Apple is apparently shrinking the battery size, but it might be because the new phones need to pack in more components and so there is less space. While Apple isn’t expected to re-design the new phone, new features include a pressure-sensitive screen — which will need internal components to help it run.

It is possible that the new phones will keep the same battery life or prolong it, as a result of features Apple is adding to the new phone. While the mAh figure refers to how long it can dispense a certain amount of charge, the actual length of time the phone will stay awake depends on how efficiently it can use that charge.

The new phones will also ship with iOS 9, the newest version of the iPhone operating system. That has special features intended to prolong the battery life — such as a “Low Power Mode” that changes various settings on the phone to try and keep it awake for longer.

Apple has also been rumoured to be adding new, more efficient hardware that will use up less power.

The rumours correspond with previous leaks, which in August showed a battery looking to belong to an iPhone in the same capacity. At the time, many speculated that it might be meant for putting inside an iPhone 6c — but that phone has now been either cancelled or delayed.