Apple has made the iPhone 6S battery smaller

The iPhone 6S, the successor to the 6, has been unveiled by Apple and includes one surprising detail: a smaller battery.

MacRumors spotted the change in the promotional video for the iPhone 6S which includes a cross-section of the device showing the battery. The iPhone 6 has a battery capacity of 1,810mAh while the new 6S has a capacity of 1,715mAh.

The first reviews for the device have not yet come out so we have no indication if this affects battery life but the change is troubling, especially as the iPhone 6's battery is less than stellar compared to the 6 Plus.

Whether Apple had a choice about the size of the battery is up for debate. The new "Taptic Engine," used to power 3D Touch, one of the headline new features in the iPhone, likely takes up more space within the phone which has come at the cost of battery size.

Luckily, iOS 9 is, according to Apple, far less power hungry than iOS 8 which could compensate for the change but we won't know for sure until the first battery tests come back.

Business Insider has reached out to Apple to verifiy this.