The iPad Pro and iPad Air models that Apple introduced today continue to offer the same 10 hours of battery life that Apple has advertised with iPads for years now, despite the addition of new, more efficient chips.
Apple's iPad Pro has an M4 chip that is built on second-generation 3-nanometer technology, and it has six efficiency cores, or two more than the M2. The device is also equipped with a more efficient OLED display, but neither the chip nor the OLED display have resulted in additional battery life.
The 11-inch iPad Pro has a 31.29-watt-hour battery, up from 28.65‐watt‐hours in the prior-generation model, while the 13-inch iPad Pro has a 38.99-watt-hour battery, down from 40.88-watt-hours.
As for the iPad Air, the 11-inch model has a 28.93‐watt‐hour, up slightly from the 28.6-watt-hour battery that was in the prior 10.9-inch version. The new 13-inch model has a 36.59‐watt‐hour battery.
Apple says that the iPad Pro and iPad Air models last for up to 10 hours when surfing the web on Wi-Fi or watching video, but that drops to nine hours when surfing the web using a cellular data network.
Source: Macrumors