1) Check Your Mackbook For Charging Requirements
2) Check Your Macbook Charger's Output & Voltage
3) Check Your USB-C PD Power Supply's Output & Voltage
20V Power Delivery (PD) is REQUIRED for the USB-C power supply.
Specification
Connector: PD USB C to MagSafe2
PD Input: 15V~20V 3A~5A
Suitable: For Macbook adapter with T-type connector
MacBook Pro 15 / 13-inch (2012-2015 Retina versions)
MacBook Air 13 / 11-inch (2012-2015 Retina versions)