The load shedding would be the last option for maintaining the integrity of isolated microgrids in the event of an insufficient generation. In this paper, a novel decentralized adaptive timer-based approach is proposed to facilitate electric vehicles' (EVs) participation in the load shedding of DC microgrids. To achieve this, an availability index, considering the traveling requirements and EV owners' preferences, is developed for prioritizing the contribution of EV chargers to the load shedding procedure. Following this, the parameters regarding the timer delays will be determined. Additionally, to improve the performance of the method in different contingencies involving different levels of intensity, the rate of change of voltage (RoCoV) is calculated and applied to the parameters of the timer-based approach. The effectiveness of the proposed adaptive method is demonstrated through the simulation of various case studies in MATLAB/Simulink.