When installing a battery, it is important to be cautious not to contaminate the battery pole with a connector damped by the acid of another battery. If the cable is contaminated then it should be washed in water solution with sodium bicarbonate and rub it with a steel brush until all the connector becomes shiny. Make sure to remove every sign of corrosion. After this operation, wash the connector in running water and dry it properly. If you notice that it is not possible to clean the connector or cable, due to high corrosion, both the cable and the connector must be replaced by new ones of the same gauge and quality of original equipment.