Application US20200161685

flowing an electrolyte of the flow battery and hydrogen gas generated in the flow battery to the rebalancing reactor;

applying a negative potential to a catalyst bed of the rebalancing reactor while flowing the electrolyte;

detecting a decrease in a ferric iron reduction rate at the catalyst bed below a threshold rate;

flowing deionized water instead of electrolyte across the catalyst bed in response to the decrease in the ferric iron reduction rate; and

indicating, after a threshold interval of rebalancing reactor operating time elapses, a request for soaking of the catalyst bed in deionized water.

an electrolyte circulating through a cell of the redox flow battery and hydrogen gas stored in electrolyte chambers of the redox flow battery, both the electrolyte and hydrogen gas flowed to a rebalancing reactor coupled to the cell;

a negative potential applied to the catalyst bed during charging of the redox flow battery;

a controller, configured with computer readable instructions stored on non-transitory memory, the instructions executable by the controller to: apply a negative potential to the catalyst bed during charging of the redox flow battery; flush the catalyst bed with deionized water upon detection of the rate of ferric iron reduction at the rebalancing reactor falling below a second threshold; and indicate a request for soaking of the catalyst bed in deionized water when an interval of operating time of the redox flow battery is elapsed.