The HTC One X9 packs a 3,000 mAh (11.55 Wh) non-removable lithium-ion battery, which is typical for a phone of this size. However, the battery life exhibited is substandard compared to other budget devices and 5.5-inch handsets, which is a disappointment
The web browsing results are particularly disappointing as the HTC One X9 falls behind the LG G5 in the LTE test. The handset is also well behind the Moto G4 Plus, which is a competing 5.5-inch smartphone with a 3,000 mAh battery. Clearly there is an efficiency issue at play here, possibly due to the display or MediaTek's SoC.
Charging times are also disappointing as the One X lacks fast charging support. Again, the Moto G4 has its own fast charging implementation that allows it to burst charge more than twice as fast. For the price of the One X9 I'd really expect to see fast charging support.