Heat Can Destroy Your Car Battery

by Andrea L. Algar
Motorheads Performance

We know that heat affects our bodies when temperatures soar into the triple digits. And, the effects can happen fast and be drastic. But did you also know that extreme heat can wreak havoc on your classic car or muscle car as well?

Yes, we've all heard of the devastating effect that high temperatures can have on your car's interior. It can cause dashboards to crack and peel, upholstery to dry out and become brittle, and can even cause your steering wheel to deteriorate! And, engine belts and hoses as well as your tires are also negatively affected by extreme heat. But did you know that it can effect the performance and longevity of your car's battery?

This is something I'm aware of first hand. Melissa restored her 1985 Jeep CJ (complete with pink engine) and had been having continued battery problems, replacing the battery five times in a single year! She had already ruled out the alternator and voltage regulator as a source of the problem. We knew it was the battery itself when Guy helped her go through her entire wiring system to make sure that she did not have any power source that could be drawing power when she wasn't running it. We tested everything and the Jeep came up with a clean check. No wiring problems or power drains anywhere in the system. What we did find, however, were that the cells in the battery were reading below the necessary levels to kick over the engine. They weren't dead, but they didn't have the starting power.


Car Battery Problems
Courtesy of: dummies.com

According to Dan Hagopian of batteryeducation.com, "If a battery is exposed to a weather extreme it may stop working, bulge, bubble, melt, damage your device, smoke, create sparks, create flames, expand, contract, and or even blow-up in very extreme cases. Weather extremes, where the ambient temperature and the relative humidity of a specific environment are altered beyond the norm may occur almost anywhere and at anytime. Here are a few such examples (this is by no means exhaustive): a weather extreme can occur outside, in a non-temperature controlled room, in a closed bathroom with the shower on, in a closed car on a hot day, in a steam-room or a sauna to name a few places. Altitude also affects batteries, for example above 15,000 feet in a non-pressurized cabin. Extreme cold also affects the battery as the internal components expand. A weather extreme can also occur even when the temperature is well within the range of the devices specification but the relative humidity increases the ambient temperature beyond the norm. If a device including the battery is exposed to weather extremes for any length of time then there will be an affect; mostly a negative effect on your device and battery."

Extreme temperatures, both hot and cold, can ruin a battery. If you've lived in Northern States where winters can be severe, you know what cold can do to a battery. Severe cold temperatures slow the chemical reactions in the battery. Since other forces are at work with the cold, such as oils becoming thicker, internal friction and longer starting cycles, your battery must work harder to start a cold engine. If your battery drains completely, it will freeze when temperatures get below zero. But, most areas of the country do not experience zero temperatures for periods long enough to permanently damage a battery just from cold. Batteries do not "die" in the cold, but more commonly become so ineffective that they cannot deliver enough of their stored power to start a car.

But cold is not the only foe of a car battery. Heat takes a toll as well. Batteries actually last 2/3 as long in hot weather areas than cold areas! Sporadic bouts of triple digit temperatures will certainly put a strain on your battery, causing it to discharge its energy at a greater rate. Even batteries that are only slightly discharged can fail to produce enough power to start a car. However, when temperatures are continuously in the triple digits, it can kill the battery. Constantly discharged batteries can lose their life quite quickly.

But, here in Texas, we're still in temperatures of 90-100 degrees on a daily basis. When it's this hot outside, the temperature under your classic car or muscle car's hood can be over 140 degrees or more! Heat causes your car's battery fluid to evaporate, damage the internal structure, and can actually accelerate corrosion! If these components become damaged, it can force your battery to charge at too high a rate and cause battery failure. If corrosion accumulates on battery terminals, it becomes an insulator and inhibits the current flow, prohibiting your battery from producing enough power to turn over your engine. And, a malfunctioning component in the charging system, like a bad starter or a voltage regulator allowing too high a charging rate, can also destroy a battery.

Your car's battery is designed to self-charge, but sometimes conditions exist that do not allow this to work properly. In order for your battery to self-charge, an idling engine, or driving on a short trip, travel in hot weather or at night will not recharge a battery. Things to consider include how much current is being diverted from your alternator to charge it, how long the current is available, and the temperature. The best conditions for your battery to self-charge is by taking a long daytime trip in warm weather.

Throw in a lot of modern conveniences like more powerful stereo systems, GPS, DVD players, radar detectors, laptop power converters and on-board computer diagnostic systems, we're putting an awful lot of strain on the battery.

So, what can you do to ensure that your battery stays in top performance condition?

• Regularly maintain your battery.
• One way to ensure that your battery doesn't die is to make sure that it is always kept fully charged.
• Keep your car battery clean. Dirt becomes a conductor draining the battery's power.
• Clean the battery case itself with baking soda dissolved in warm water.
• Clean the battery terminals periodically with a wire brush to ensure good connectivity and prevent corrosion around the terminals.
• If you still run an old-style battery in your classic car, (you know, the"tar-tops" that needs to be topped off with either distilled water or acid. check it regularly in hot weather.
• If you do have a battery that is discharging, always put it on a trickle-charge and never a full power quick charge, as this will further damage the battery, reducing it's life even faster.
• If you suspect a problem, have your battery tested by a power output tester to see if it needs replacing.

There are a lot of myths surrounding batteries. Guy Algar explains, "Today's new batteries, unlike the batteries originally sold with your 1955 Chevy, will not dissipate or "leak" out when stored on a concrete floor. Still, all batteries have a "leak rate" of about 1 to 15% per month when left sitting, and will fully discharge over time. High temperatures only accelerate this process, and will severely shorten the life of a battery you leave sitting on a shelf in your garage." A battery stored at 95 degrees Farenheight will discharge twice as fast as one stored at 75 degrees.

Charging a low battery can easily be done with the newer at-home charging systems which are available at parts stores or on-line auto parts suppliers. They can range from basic inexpensive "no frills" systems, to elaborate systems that check battery performance, as well as provide a wide range of charging options. But, even with these systems, it's important to know how much of a charge to give, and when. Overcharging will shorten the life of your battery. You generally need to lower the charging voltage as the temperatures climb. For more information on properly charging your car's battery, check out the video How To Use a Portable Car Battery Charger (Video).

We covered how heat affects your body in an article here in July. If you missed this vital information, see "Working Safely in Extreme Heat - Summer Temperatures Can Be Dangerous!"

REFERENCES:
batteryeducation.com - Temperature Affects Batteries?
ehow.com - What Can Kill Your Battery?
howstuffworks.com - How Batteries Work
nuclearpowertraining.tpub.com - Constant Voltage Charging and Trickle Charging
Pacific Power Batteries - Myths About Batteries
science.discovery.com - How Car Batteries Work (Video)
weather.com - Caring For Your Car During Summer

RESOURCES:
edmunds.com - A Shocking Expose: Your Car's Battery
ehow.com - How Do Auto Battery Chargers Work (Article & Video)
howcase.com - How To Use a Portable Car Battery Charger (Video)
Top10Reviews - 2012 Best Car Battery Charger Comparisons and Reviews

ABOUT THE AUTHOR:
Andrea L. Algar is co-owner of a classic car performance and restoration design shop in Leesville, Texas. Motorheads Performance specializes in repairs, maintenance, performance upgrades and restorative work on cars and trucks from the 1920’s through 1970’s. Her husband Guy L. Algar is a Mechanical Engineer with over 25 years experience. He holds 5 ASE Certifications from the National Institute for Automotive Service Excellence and has been working on old cars and trucks for over 37 years. Together they share their passion for old cars and trucks with other enthusiasts from around the country.