The invention relates to provides a method for operating an iron salt battery, ISB, device, the ISB device comprising an ISB cell or a stack of ISB cells, a positive tank containing a positive electrolyte and a negative tank containing negative electrolyte...

The invention provides a pH-probe for determining a pH value of an electrolyte of an iron salt battery, ISB, device, the pH-probe comprising: a Fe(II)/Fe(III) reference electrode comprising a reference chamber containing a solution with predefined concentr...