There are many reasons why mobile phones charge slowly, such as unstable voltage, lithium batteries will automatically open the protective barrier to prevent frequent charging. Or the discharge process is confused with the charging process, the charger plug is different, the charging cable is not plugged in, and so on.
In addition, the mismatch of the charging plug, the power of the plug is not enough, or the mismatched USB charging cable, due to the different support currents, will also lead to slow charging of the mobile phone, replace an original or certified charging head and data cable can be solved.