Adaptation to high current using low external resistances eliminates power overshoot in microbial fuel cells

► Power density curves often show power overshoot, where the current decreases as the voltage is reduced. ► Microbial fuel cells (MFCs) showed power overshoot when acclimated to higher resistances but not lower resistances. ► Power overshoot was eliminated by acclimating all reactors to a low external resistance of 5 Ω. ► MFCs that did not show power overshoot had redox activities over a broader range of anode potentials in first derivative cyclic voltammetry plots. ► These results show that power overshoot can be eliminated in MFCs, making it possible to more accurately estimate power production by the MFC.