POCO X2 charging speed is tested to find out the overall Charging time of POCO X2 4500mAH battery. It supports 27W Fast charging also, included the 27W fast charger and it chargeable through USB Type-C port. So, let’s start to find out the Poco X2 charging time. Firstly, I have made a state in both Phone ON & OFF condition to find out how much battery percentage is charged in each state. Likewise, the POCO X2 heating condition is monitored thoroughly during the POCO X2 charging test duration. 
The POCO X2 charges about 44% of battery on the first 30 minutes of charge also, during this period the phone is in OFF state. Now the POCO X2 turned ON & on the next 30 minutes while, the phone is switched ON with Wi-Fi & Internet working condition. In this condition, the POCO X2 charges from 44% to 66% of battery in next 30 minutes. Overall the POCO X2 charges about 66% of battery in 1 Hour. However, in last 30 minutes during phone ON condition it, charges 22% of battery and to be note that, during phone OFF condition, it doubles the charging level of 44% of battery in first 30 minutes. 
After that, in next 30 minutes, from 1 hour to 1 hour 30 minutes it charges 66% to 90% of battery. So totally, 24% of battery charged in next 30 minutes and it almost similar to last 30 minutes which is 22% of battery. Finally, the POCO X2 charges slowly on charging from 90% to 100% of battery. It takes a time of 25 minutes to charge 10% of battery between 90% to 100% battery. Therefore, the POCO X2 finally fully charged the 100% of battery in 1 Hour 55 minutes. To sum it up all,

In Phone OFF state:

First 30 min                                       – 44% charged (0% to 44%)

In Phone ON State

Next 30 min (In 1 Hour)                    – 22% (44% to 66%) 

 

Next 30 min (In 1 Hour 30 Minutes) – 24% (66% to 90%)

 

Final, 25 min (In 1 Hour 55 Minutes) – 10% (90% to 100%)

Is POCO X2 Heating while, Charging

Yes, POCO X2 heat slightly after turning on the phone in next 30 minutes. The POCO X2 is not heat up in phone off state for first 30 minutes and during that time it charges 44% of battery. After turning ON the phone and in next 30 minutes it charges about 66% of battery at this point, it starts to heat slightly. The heating is continued but the temperature is not increased until the 100% of charge. Overall, the POCO X2 has little heating while charging after 66% of battery.