The most evident symptoms are: - The densimeter always registers a low density in the electrolyte although the element is always subjected to the same discharge as the other elements. – Its current is lower to the rest of the elements during discharge and higher during charge. – It is impossible to charge the battery fully. – The two plates, positive and negative display a light colour. – In extreme cases, one of the terminals stands out excessively due to the deformation of the plates.