https://www.cnet.com/news/the-galaxy-note-9-may-be-getting-a-big-battery-upgrade/

How will the Galaxy Note 9 beat out last year's Note 8? Perhaps by packing a larger battery.

The Note 9 is rumored to have a 4,000mAh battery, according to mobile tipster Ice Universe (via SamMobile). Ice Universe has a track record of leaking unreleased phones, but this should still be treated as a rumor until the Note 9 is officially announced. Besides battery size, the Note 9's battery life may also be affected by things like screen size, software and power efficiency.