The iPhone 8 has a battery capacity of 1821mAh, which is only slightly larger than the iPhone 6S and much smaller than the iPhone 7's 1960mAh.
In terms of charging, although the iPhone 8 supports fast charging, the standard is still 5V\/1A charging head, so the charging time is longer, and it takes 148 minutes to fully charge.
In moderate use, with the brightness set in the middle, the iPhone 8 lasted 8 hours and 37 minutes in continuous use.