As you can see, comapred with the PCB in the video, the schematic is now changed. We don't have the TP4056 modules anymore. In this case we just have a micro-USB connector for 5V. That is connected to an external boost converter and the converter is connected to the external 2S BMS. The BMS is connected to the batteries as we have seen before and then the 8.4V output is connected back to the PCB. We have some female connectors for that, H1 and H2 on the schematic.