The efficiency of vibration-based energy harvesters is often constrained by low vibration amplitudes and limited responsiveness beyond the resonant frequency. To overcome these limitations, mechanical amplifiers and spring bumpers can be employed to enhance excitation amplitude and magnet velocity within a compact device. This study presents a nonlinear oscillator supported on pre-compressed coil springs with high-stiffness bumpers acting as motion limiters. The resulting collision effects and friction introduce hysteresis, significantly influencing the system’s dynamic response. An electromagnetic model with position-dependent inductance is developed, and the identified system parameters enable numerical analysis of energy recovery and dynamic behaviour. Selected numerical predictions are compared with experimental observations, demonstrating the model’s effectiveness.