Under ideal conditions, one automobile battery can last up to six years, but several factors decrease this optimal lifetime. A study of 2,769 sample 12 volt batteries conducted in 2004 showed that the average lead acid battery life is 50 months. Batteries in the northern US had an average life of 56 months compared to those in the south which had an average life of 43 months. Lead acid batteries last longer in cold climates as warm climates increase water loss and sulfation. Car battery life span range is 2 to 5 years. The most simple and effective way to extend the life of an automotive battery is to keep it charged close to 100%.