Blog, 25th Anniversary

The Effects of Heat on Your Heavy-Duty Battery

Most people know that cold weather affects battery performance. But what about the effect of summer heat on your heavy-duty battery? The fact is, that extreme heat is also detrimental to battery life.

Both conventional flooded lead acid batteries and Absorbed Glass Mat (AGM) batteries suffer water loss in extreme heat—and water is essential to the electrochemical process within the battery.

Lead acid batteries function using an electrochemical process in which lead plates react with an electrolyte. As the temperature rises and a battery absorbs heat, the process speeds up exponentially. This results in an increase in plate corrosion, self-discharge, and over a prolonged period of time, sulfation. Sulfation is the development of large crystals on the negative plates, blocking surface area and impeding battery performance.

Heat Comes from Several Sources

There are also other factors that expose heavy-duty batteries to excessive heat other than the climate. Over the past decade, truck designs have been focused on achieving better aerodynamics in order to improve fuel mileage. In these design modifications airflow is directed over, above and behind the vehicle, rather than directing it to cool the engine and other heat generating components in the engine compartment and underneath the vehicle. Often, the position of the battery box is closer to heat generating components. In short, the battery is in a hotter location that isn’t as efficiently cooled. Temperatures can reach 140°F and higher.

Simply stated, batteries discharge faster in excessive heat. Unless the battery design includes features that help protect the battery from the heat, or if preventive measures aren’t taken, battery life and performance are likely to be affected. It is estimated that constant exposure to heat above 77°F cuts battery life in half for every 15°F rise in temperature.

What You Can Do

Choose wisely. Selecting a battery that stands up better to excessive heat is a good place to start. Non-spillable and virtually maintenance-free, AGM ODYSSEY® batteries, manufactured with Thin Plate Pure Lead (TPPL) technology, can perform in extreme temperatures as high as 176°F (80°C). They also offer slower self-discharge rates, less corrosion and faster recharging than alternative battery chemistries.

Know your battery is fully charged. You can’t assume that vehicles in use everyday recharge their batteries. Because excessive heat causes faster discharge, it is a good practice to use a maintenance charger on idle vehicles exposed to excessive heat.

Keep track of the installation date. Plan to replace your battery within the manufacturer’s recommended time frame. Knowing that excessive heat can have an effect on battery life, there’s no need to press your luck.

All things considered, there isn’t a lot you can do about summer temperatures, but you can put yourself in a better place down the road by knowing how heat affects a heavy-duty battery—especially when it comes to buying a new battery or getting longer battery life from the product you already own. Always be sure to follow the manufacturer’s guidelines for battery care and handling and direct any questions to your battery professional.

This year, EnerSys® marks 25 years of ODYSSEY® battery production. To follow the ODYSSEY® battery 25th Anniversary journey, visit our website at or connect with us on InstagramTwitter, and Facebook by using the hashtag #MYODYSSEY.


EnerSys, the global leader in stored energy solutions for industrial applications, manufactures and distributes energy systems solutions and motive power batteries, specialty batteries, battery chargers, power equipment, battery accessories and outdoor equipment enclosure solutions to customers worldwide. Energy Systems, which combine enclosures, power conversion, power distribution and energy storage, are used in the telecommunication, broadband and utility industries, uninterruptible power supplies and numerous applications. Motive power batteries and chargers are utilized in electric forklift trucks and other industrial electric powered vehicles requiring stored energy solutions. Specialty batteries are used in aerospace and defense applications, large over-the-road trucks, premium automotive, medical and security systems applications. EnerSys also provides aftermarket and customer support services to its customers in over 100 countries through its sales and manufacturing locations around the world. With the recent NorthStar acquisition, EnerSys has solidified its position as the market leader for premium Thin Plate Pure Lead batteries, which are sold across all three lines of business. More information regarding EnerSys can be found at