Why is ZUS not fast-charging my device?

Fast-charging can be affected by a number of factors. The first thing you can check is your charging cable. If you are not using your device's OEM charging cable and using a generic one, fast-charging may not work. In our laboratory tests, with a good charging cable, the charging current can reach 2.4 amperes. Also, ZUS will not be able to fast-charge newer devices running on processors with Qualcomm's Quick Charge technology, as they require certified accessories to work. ZUS can only charge such devices at the standard/normal speed.