For detecting swelling in batteries supplying power to electrical equipment, at least one contact sensor such as quantum tunneling composite (“QTC”) based pressure-capacitive sensor coated on one surface with a layer of conductive material such as indium tin oxide (“ITO”) or a capacitive sensor coated with the same conductive material is used for attachment to each battery. A capacitance measuring module including a microcontroller is connected to the contact sensor and measures the capacitance of the ITO—coated conductor. If the capacitance under measurement represents an increase in capacitance exceeding a predetermined threshold, indicative of battery swelling, a call for battery replacement and interruption of battery power to the electrical equipment are initiated.