During its first usage like newly bought products and if you haven't used it for 3 months or over, you'll need to charge it regarding the rest of the power. The suitable temperature is between 5 degrees to 35 degrees If the temp is over or below, it will cause the charger can't charge normally or can't charge at all.

To keep sufficient battery, it's advised to charge 2 times separately to save up the charging time too. It is normal for the temp of the machine to go up at using and charging time.

Specifications:

Model: C Series
Main Power: 2.5W
Battery: Lithium-ion battery 18500/1200mAh 3.7v
Charging Seat Input: 5v DC 500mA