When Apple announced the new iPhone 8 and iPhone 8 Plus, it didn’t really reveal the battery sizes of both devices. Now it’s been discovered that the batteries on thew iPhone 8 models are actually smaller than those of the iPhone 7 and iPhone 7 Plus.

Tech leaker Steve Hemmerstoffer (@OnLeaks) revealed on Twitter that the iPhone 8 features a 1,821 mAh battery, while the iPhone 8 Plus comes with a 2,675 mAh battery. Hemmerstoffer got his information from a product listing on TENNA, the Chinese equivalent of the American Federal Communications Commission (FCC).

For comparison, the iPhone 7 comes with a 1,960 mAh battery, while the iPhone 7 Plus features a 2,900 mAh battery, according to MacRumors. The iPhone 8 and iPhone 8 Plus’ batteries are actually smaller than their predecessors’ batteries.

Despite of this, Apple claims on its website that the battery life of the iPhone 8 and the iPhone 8 Plus is “about the same as” the iPhone 7 and 7 Plus. It’s also important to point out that Apple doesn’t actually list the battery capacities of the two newest phones on its website. Instead, the company just list battery life estimates based on the type of usage.

It's possible that the battery life of the iPhone 8 and 8 Plus are the same with their predecessors. Perhaps Apple has managed to make that possible through software optimization. Another thing that might be helping the new iPhone 8 models have longer battery life despite the smaller battery capacity is Apple’s new A11 Bionic chip.

Apple claims that the new A11 Bionic processor is able to be more powerful than its predecessors while also being more power efficient. The A11 Bionic processor features 6-cores; two performance cores which are 25 percent faster than the A10, and four high-efficiency cores which are 70 percent faster than the A10, according to TechCrunch.

The A11 Bionic chip also makes it possible to run augmented reality (AR) experiences on the new iPhone 8, 8 Plus and the iPhone X. How AR on the iPhone 8 and 8 Plus will affect battery life remains to be seen. Although it’s likely that the smaller batteries on the two iPhone 8 models might turn off some users, the inclusion of fast-charging and wireless charging support might be enough to get them onboard.

Apple’s three new iPhones support wireless charging under the Qi wireless charging standard. The Qi standard means that users will be able to take advantage of the wireless charging feature by buying third-party charging pads. Apple has already announced its own wireless charging pad called the AirPower, but that won’t be out until next year.

As for fast-charging, users will have to buy Apple’s USB-C Power adapters for that, as well as the USB-C to Lightning Cable. The cheapest adapter is the 29W model which costs $49, while a 1 meter USB C to Lightning costs $25.

In addition to revealing the battery capacities on the new iPhones, the TENAA listing also revealed that the iPhone 8  comes with 2GB of RAM, while the 8 Plus features 3GB. These are the same RAM sizes on the iPhone 7 and iPhone 7 Plus.

The iPhone 8 and iPhone 8 Plus will be available to pre-order on Sept. 15, while both devices are expected to be released on Sept. 22.

iPhone 8 The iPhone 8 and iPhone 8 Plus features smaller batteries than the iPhone 7 and iPhone 7 Plus. Photo: REUTERS/Stephen Lam