MACBOOK NOT CHARGING? 8. Check loose battery connector

 

8. Check loose battery connector

All pre-2016 MacBooks use nine-pin connectors to connect the batteries to the logic boards. Pin 6 is used for battery detection. When you connect a battery to the logic board, this pin will signal the battery’s internal “smart" circuit to turn on the “safety switch" called MOSFET. Therefore, the electric current can freely flow in and out of the battery. This safety design prevents accidentally shorting the battery terminals and causing damage to the battery or even fire       

Also, SMC uses pins 4 and 5 to communicate with the battery. As all these pins 4, 5 and 6 carry low-voltage electronic signals, any of them slightly loose contact will cause MacBook not to charge.

Make sure there is no dirt or liquid on the connector and socket. Use cotton buds with at least 95% alcohol to firmly clean the pins and reconnect the connector.

In recent MacBooks, Apple has a new design on the MacBook battery. The battery power terminals are connected to the logic board and secured by a T5 screw to provide better contact. On the other hand, the battery uses a separate flex cable to communicate with the logic board, as shown below:

The SMC or T2 Security chip uses a flex cable to communicate with the battery. If the flex cable is not connected correctly, your MacBook will not charge the battery or even can’t recognise the battery.

Check the connectors on the logic board side and the battery side. Clean the connectors with alcohol. Make sure the flex cable is firmly locked inside the connectors.