Poster: Charge My Phone As I Instruct.

Charging mobile devices fast alleviates users' impatience in waiting for their devices to be charged. So, fast charging has been the focus of both industry and academia, developing and deploying various technologies, such as Quick Charge by Qualcomm, TurboPower by Motorola, Flash Charge by OPPO, etc. Fast charging, unfortunately, accelerates the capacity fading of device battery because it follows the Constant Current, Constant Voltage (CCCV) charge principle without considering the behavior of how users charge their devices. CCCV charging principle is a two-phase charging process consisting of (i) Constant-Current Charge (CC-Chg) and (ii) Constant-Voltage Charge (CV-Chg) [2] where CV-Chg is usually triggered at the end of charging (e.g., 80-100%) to stabilize the battery condition. However, fast charging technologies are agnostic of users' available charging time, resulting in premature termination of the planned charging if users only have limited time. This, in turn, leads to an incomplete CV-Chg phase or even skipping it completely. From our empirical measurements, we discovered that CV-Chg relaxes the batteries and slows down their capacity fading by up to 80% [1] incomplete CV-Chg shortens the battery life significantly over time!