1)Check charger indicator light, green light normal; If the red light is blinking or off, replace the charger.
2) Check the charging port again. If the charging interface line is loose and falls off, the charging interface should be replaced.
3) Finally check the battery, whether waterproof marked become red, If become red ,The water into the battery and need to replace the battery; A multimeter is available to check whether the battery output voltage is normal.