There are several possibilities:
1, the mobile phone detection and display problems, that is, it shows charging, but it is not, but detected that the electricity is indeed transmitted to the plug pin, but the back is disconnected. I don't know why you can't charge it and make ends meet? But these cases are generally rare.
2. The battery is starting to fail. Lithium batteries have a certain charging and discharging cycle life, and the capacity of the battery decreases for a long time (equivalent to a smaller battery), because the capacity is smaller, the charging is more and more frequent, and each charging and discharging cycle will reduce the capacity, the internal resistance increases, the nausea cycle, until the failure. Your current battery capacity may be very low, just like a \"button battery\" with great internal resistance, which does not charge much electricity and does not discharge much electricity.
3. The internal resistance of the charging cable is large. Although you are new, but do not rule out the new wire will also be large internal resistance, it is best to find a good line to try. USB voltage is only 5V, the wire has 1 ohms, the maximum short-circuit current is reduced to 5A, there are 10 ohms, the maximum short-circuit current is reduced to 0.5A. Coupled with the internal resistance of the mobile phone, it is normal to charge more than you can afford. Many cottage power lines with poor quality wire, small diameter, serious surface oxidation, to meet the resistance below 1 ohms, it is not easy.
4. The contact resistance at the joint is too large. The interface between the charging line and the power source, the interface between the charging line and the mobile phone, if the resistance is too large, it will lead to the result of the third point.
5, charging head failure, can not provide enough voltage, current. Just try a good charger.