The paper assesses the possibility of using planetary differential variators to change the gear ratio of the kinematic control chain of a flywheel accumulator. The possibility of using a differential mechanism as a variator for the flywheel battery drive is related to the calculation of the required power for the transmission ratio control. The equation of the power in the engagement of central wheels with the satellite was derived as a ratio of the power ratio. The obtained ratios of speeds and capacities of the differential mechanism allowed us to prove that the flywheel accumulator can be used without being included in the control system, by using the property of self-leveling the kinetic energy of the links of the planetary differential variator.