Car batteries use lined cell walls within the battery to store electricity. These cell walls are not infallible since car batteries are subject to extreme temperatures. Those extreme temperatures can shorten the lifespan of the battery. The answer to protecting the battery from high and low temperatures is insulation. Taking measures to insulate your battery will prolong the life of the battery which inevitably is a money-saving activity. Insulating the battery is simple and easy to do.
Purchase a battery sleeve from a manufacturer or auto parts retailer. These sleeves are typically made of hard plastic or an acid-resistant cloth and conform to the size and shape of your battery.
Apply an insulation kit to the battery. Auto parts retailers market kits that apply directly to the battery to prolong the life of the battery. These kits usually have a plastic pad to go under the battery and adhesive material that applies directly to the battery.
Obtain an OE (original equipment) battery sleeve. Most vehicles sold new come with an insulating sleeve that seals the battery into a relatively contained environment. Auto shops often discard these or owners lose them when doing maintenance. You can purchase a new one direct from the auto manufacturer or find used ones which are just as functional at salvage yards.
Do not use cloth that is not rated as acid-resistant to insulate your battery. Standard cloth can become volatile within an engine compartment, creating a fire hazard.