Batteries have needs. They need to be of a quality construction, connected with good solid non-corroded connections, and must have a charging system that works correctly. They need to be used, kept clean of debris like dirt, dust, mud, and the like. They need to be maintained (kept charged) when the load is hooked up (either by an external charger when stored, or by an alternator when driven). Vehicles lately have what is called 'parasitic loads'. This means there is a constant draw on the battery. If it's charge isn't replaced before damage to the battery, then a replacement must be bought. For years we know our cars have a problem with batteries that are not capable of supplying full voltage/current when demanded. Keep this in mind when replacing the battery, and storing the car. It IS this simple.