Do I need the Extended Module?
This depends on what you need. 123SmartBMS is a stand-alone BMS systems and does not require the Extended Module. The Extended Module is primarily designed for vehicles, boats, CAN bus applications or customers in need of a more configurable solution. If you want to configure relays to switch based on via software chosen parameters or need the BMS data on a CAN bus network, the Extended Module is a perfect match.