This study investigates the magnetocaloric properties and refrigeration performance of batch-prepared (La, Ce) (Fe, Mn, Si)₁₃H_y alloys. After heat treatment and hydrogenation, the Curie temperatures of M1, M2, and M3 were 292.9 K, 287.8 K, and 283.9 K, respectively, decreasing with higher Mn content. Arrott plots indicated an itinerant-electron metamagnetic transition. M2 exhibited the highest isothermal magnetic entropy change of 12.0 J/(kg·K) under a 2 T magnetic field, with a full width at half maximum of 11 K. Relative cooling capacities (RCP) were 110.2 J/kg, 132.0 J/kg, and 110.0 J/kg for M1, M2, and M3, respectively. Adiabatic temperature changes measured under a 1.5 T magnetic field were 3.48 K, 3.14 K, and 2.96 K for M1, M2, and M3, respectively. A maximum refrigeration temperature span of 16.9 K was achieved by cascading the alloys at an ambient temperature of 295 K.