– Apply grease or petroleum jelly to battery terminals.
– Use tin, silver or aluminum plated copper terminals.
– Fix alternator/generator causing overcharging of battery.
– Replace leaking or damaged battery.
1- Grease (preferably silicone grease) and petroleum jelly have the tendency to protect copper battery terminals from corroding until these lubricants themselves do not get polluted with battery acid, these can create a fairly good protective shield against corrosion causing substances. Clean the corroded terminals properly with corrosion cleaner or solution of caustic soda in water. Apply appropriate amount of grease or petroleum jelly. I would highly recommend using silicone grease because it won’t get damaged with leaking battery electrolyte.
2- Tin, silver or aluminum plated copper terminals can withstand corrosion and increase life span of battery terminals. These might be a bit expensive but worth the extra money that you would spend on them. Silver and aluminum usually develop thin layer of oxides that prevent further corrosion.
3- Your car alternator supplies power to lights, audio system, sensors, ECU, power windows, electric power steering and other electrical components while car engine is running. If alternator is bad and it is not cutting off charging, it will lead to overcharging of battery which is highly fatal for battery. Battery can die or it may start leaking its electrolyte due to the cracks or loose joints developed in plastic container by overheating of battery. This can also cause battery terminals to corrode. So fix your car alternator to extend battery life and fix the corrosion issue.
4- If you observe that your battery top is wet with odd smell of acid or it is leaking electrolyte from any joint, you should consider replacing the battery. Battery acid can not only corrode battery terminals but can also damage metallic parts under the hood if it comes in contact with them.