An agricultural baler (10) includes a main bale chamber (26), a plunger (30) reciprocally movable within the main bale chamber (26) through a compression cycle, a flywheel (44) associated with the movement of the plunger (30), and a driveline (50) associated with the flywheel (44) and couplable with a power take-off (PTO) of a traction unit. The agricultural baler (10) is characterized by an auxiliary power system (52) coupled with the driveline (50). The auxiliary power system (52) includes a power indicator (64, 64') providing an output signal representing a parameter associated with power usage during the compression cycle of the plunger (30), a power device (54, 58) for receiving power from and/or transferring power to the driveline (50), and an electrical processing circuit (62) coupled with the power indicator (64, 64') and the power device (54, 58). The electrical processing circuit (62) is operable for receiving the output signal(s) and controlling operation of the power device (54, 58), dependent upon the output signal(s).
