Magnetically coupled energy harvesters have been demonstrated to achieve broad tuning of nonlinear behaviors and multi-directional dynamic response by adjusting the relative spacing among magnets. Such flexibility permits a wide accommodation to diverse ambient base excitations for energy conversion and capture. Yet, the magnetic coupling of an energy harvesting system has not been examined as a useful means to enhance energy harvesting outcomes when the excitation source contains the impulsive excitations commonly encountered in ambient environments. To obtain new understanding on the effectiveness of magnetic coupling, a nonlinear vibration energy harvesting system is devised and studied for the electrodynamic responses and direct current power charging that are enabled by impulsive excitations. By comparing experimental and numerical simulation results, the energy harvesting system model is firstly validated. The studies demonstrate the sensitivity of total energy collection on change in the impulse characteristics. The findings reveal that nonlinear snap-through behaviors induced by bistable nonlinearities with magnetic coupling are effective for DC power charging, so long as an impulsive excitation threshold is met. Results from this research emphasize the importance of accurately quantifying the magnetic coupling effects towards characterizing the sensitivities the energy harvesting system when subjected to impulsive excitations.