How to Insulate Your Car Battery

Updated: Aug. 13, 2023

Everyone knows that cold weather is hard on a battery. But did you know that high heat is just as bad?

Family Handyman

It’s common knowledge that extreme temperatures can wreak havoc on our car batteries. Many of us prepare for the biting cold of winter, ensuring our car batteries are adequately insulated. But how many of us consider the sweltering summer months? Both freezing cold and excessive heat can significantly impact a battery’s lifespan and performance.

Cold vs. Heat: The Dual Threats to Your Battery

Almost everyone recognizes the strain cold weather places on a car battery. The lower temperatures reduce the battery’s capacity, meaning it has less power to start your car. This is particularly problematic on cold mornings when you need your vehicle the most.

But it might come as a surprise to many that high heat is an equally formidable adversary. Prolonged exposure to high temperatures can cause the battery fluid to evaporate, leading to a weakened battery structure and, eventually, failure. The combination of heat from both the environment and your vehicle’s engine can speed up this deterioration process.

The Role of the Battery Insulating Jacket

This is where the battery insulating jacket steps in. Primarily seen in late-model cars, this jacket acts as a protective barrier around the battery. Its dual-purpose design helps the battery retain necessary warmth during winter while shielding it from excessive engine heat in summer months.

The consequences of neglecting this insulating jacket are stark. Removing it or not ensuring its proper fit can reduce the battery’s life by nearly two-thirds. This reduction is even more pronounced for those residing in particularly hot climates.

Changing Batteries: Don’t Forget the Jacket

It’s vital, therefore, always to reinstall the battery insulating jacket when replacing or checking your battery. It’s not just about fitting the original jacket back on; sometimes, we might upgrade to a larger battery, making the original jacket obsolete due to size differences. In such cases, it’s imperative to get a replacement that snugly fits the new battery. After all, a loose jacket can’t perform its protective function effectively.

Does Your Vehicle Need a Jacket?

If you’ve recently bought a vehicle or replaced its battery and noticed it doesn’t have an insulating jacket, it might be time to make a trip to your local auto parts store. Most modern vehicles come with them as standard, but older models or certain brands might not have this feature. Adding a jacket is a small investment in prolonging your battery’s life and ensuring consistent performance.


Both the scorching summers and frigid winters present challenges for our vehicle batteries. Being proactive by ensuring a well-fitted battery insulating jacket can mean the difference between a long-lasting battery and one that gives out when you least expect it. Remember, a little care and attention now can save you time, money, and potential headaches in the future.