you can in principle build a 48 V pack from sixteen 3.2 V LiFePO₄ cells placed four-per-GC2 case and then wired in series, but there are several important practical and safety considerations: all cells must be closely matched by capacity, state-of-charge and internal resistance (prefer new cells from the same batch), the BMS must be a proper 16-S unit sized for the motor’s continuous and peak surge currents and must have correct, short, low-resistance sense lead routing to each cell/group, you should use stout busbars or heavy gauge cable (and keep series conductor lengths as short and symmetrical as possible) to avoid voltage drops and uneven heating, provide temperature sensors and good thermal coupling/ventilation in each GC2 module, fit cell-level or group fuses and a main battery fuse/contactor for safety, mechanically secure and isolate each cell so vibration won’t loosen connections or damage cells (important because vehicle vibration affects bearings and electrical connections alike), and plan for proper charging (LiFePO₄-specific charger and BMS settings), enclose the pack to protect from moisture and impact, and accept that DIY packs carry higher liability and failure risk than commercial integrated packs—if you’re not very comfortable with high-current battery work, have a qualified technician review or build it for you.
