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Car Batteries: Proper Storage to Prolong Battery Life

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Car batteries are expensive, can have a short lifespan, and we rely on them every day in our vehicles! It is necessary to store car batteries properly to be able to maximize battery life especially since we rely on them so heavily to perform properly. I have had many questions about storing batteries, and factors that affect the lifespan of batteries. Here are some of the questions I have had and answers that I have found.

With so many opinions that seem to contradict each other, what are the real answers to questions such as the right temperature to store batteries at and if they drain faster at different temperatures. Also questions such as can I store batteries on concrete. The response often given to this question and other common beliefs about batteries are often not true and are clarified here.

Battery Slowly Drains While in Storage

Car batteries very slowly lose their charge even when not in use.

Batteries slowly drain when in storage because the reversible chemical reaction that occurs in a battery producing electricity will occur very slowly even when not in use. Electrons on the anode side of the battery are slowly produced from the chemical reaction and can also seep through the insulator that divides the electrodes.

The lead anode and sulfuric acid slowly react even when not being used and it is only a matter of time before the reaction has taken place entirely and must be reversed by recharging the battery.

Modern batteries are constructed to prevent draining and do their jobs very well. But they still seep and slowly drain.

Batteries will drain faster as when they are stored in a hot environment because the heat can speed up the natural chemical reaction that occurs while the battery sits.

The best thing you can do to prolong the life of the battery while it is stored is to keep a trickle charger on the battery. Car batteries are not designed to be deep cycle batteries. For them to operate properly they should always be topped off.

Car batteries are designed to best be stored with a trickle charger since, because when they sit in the car, the alternator is continually charging the battery. They are never expected to be drained completely, so they are designed that way. 

Does a Car Battery Drain when Stored on Concrete?

A modern car battery will not drain when placed on concrete. Modern car batteries are encased in polypropylene (hard plastic) and insulate the battery very well. Electrolyte seeping has been virtually been removed by better insulating batteries but there are a few other precautions to take when storing a battery.

A common myth is that you cannot store a battery on concrete or it will discharge faster than if stored elsewhere. This comes from the fact that concrete holds moisture very well and by storing the battery in a moist environment, seeping from the battery is greatly increased. Storing the car battery is acceptable since modern batteries are constructed with better insulating components than they used to.

Old batteries were constructed of materials that were less insulating and were more prone to losing electricity through the environment. It is true that batteries made before the year 1950 should not be stored on concrete since some of the oldest batteries were contained in wooden boxes, but today it is fine to store on concrete.

Modern car batteries are encased in hard plastic and keep the electrolytes in the battery well insulated from whatever environment the batteries are stored in.

It is safe for you to store modern car batteries on concrete without the risk of them draining due to superior insulating materials used in car batteries today, but the temperature of the environment where you store the battery is very important.

Best Way to Store a Car Battery

The most important factors when storing a car battery is the temperature, location, and use of trickle charger. By storing your battery at no more than 75 degrees Celsius, in a dry location, and with a trickle charger you will get the maximum life out of your battery.

The Right Temperature for Storing a Car Battery

Car batteries last longest when they are stored in a dry area between 65 and 75 degrees Fahrenheit. The temperature matters when storing a car battery to keep it from draining so quickly. Just as heat increases the speed of a chemical reaction, storing a car battery at a higher temperature will cause it to drain faster.

It has been proven that a battery will discharge at a significantly slower rate at a cool temp. So it is critical to keep batteries stored in an environment that does not get too hot.

Batteries discharge at a slower rate at a low temperature because the chemical reaction occurring in the battery is slowed down. 

The Right Location for Storing a Car Battery

Car Parts in Storage

Location matters storing a battery at right temp and humidity. Store unused car batteries in a warm cabinet in your garage or inside a closet.

Car batteries produce a very small amount of hydrogen gas and is something to consider when choosing a place to store the battery. Ensure that there is at least some ventilation in the area where the battery is stored to prevent the accumulation of hydrogen gas.

Since garages are often uninsulated, store the battery in the back of a warm coat closet to keep the battery warm and dry. But, garages are the best place to store a battery as long as it is between 50-75 degrees Fahrenheit inside since the best way to store a battery is with a trickle charger

Trickle Charger on a Car Battery

By far, leaving a trickle charger on a car battery that is stored or not in use for long periods of time is the best thing that you can do to prolong the life of the battery. A trickle charger prevents the battery from draining and prevents the chemical reaction that will occur otherwise reducing the life of the battery.

Battery Sleeve for Storing a Battery

A Battery Sleeve or other insulating box can help keep a car battery stored at the appropriate temperature. Battery sleeves can be as simple as a plastic box but can also be insulated and provide the ability to store the battery in the sleeve in harsher environments.

Some claim that wrapping a car battery in a small bit of reflective material while in the car will prolong the life of the battery since it will be insulated and prevented from reaching high temperatures in the hot engine compartment.

Thin battery sleeves make no significant difference to prolong the life of the battery and are a waste of money unless they fully enclose the battery and provide a decent insulating barrier.

A plastic battery box like this will enclose the battery enough to provide a significant amount of insulation. This battery box is very inexpensive but made my a reputable company and is definitely worth the purchase to keep a battery dry, warm, and stored properly.

Batteries can also be stored in many other insulated boxes or areas of your choice. Just don’t forget they need a bit of ventilation!