1. Make sure the power cable is fully plugged into the unit. The port is tight on a new unit. Push the cable all the way to the end.
2. I8 has deep charging channels to accommodate batteries of different sizes. When charging small batteries such as 16340 or 14500, the contacts on the charger might not be able to connect to the positive/negative end of the battery if the battery is not settled properly. If the charging indicator does not lighten up, take a look at both ends of the battery and lift either end slightly so that the metal surface contacts each other.