What Temperature Kills a Car Battery?

Owning a Tesla in Texas is great. With Tesla Headquarters and Elon himself moving to Texas, we can expect a big push for investment in Tesla charging infrastructure and other EV initiatives coming right around the corner. However, one challenge many Texans are running into is maintaining effective charging practices during extreme weather fluctuations. 

Whether it’s the sweltering summers or the frigid cold desert winters, Texas is known to experience some serious temperature swings. Thus, you may wish to get a quick answer to the question, “what temperature kills a car battery?”

The big challenge here is that the lithium-ion batteries that power your Tesla tend to perform great in normal weather conditions but encounter some challenges when charging in extreme heat or near freezing temperatures. 

To combat these challenges and answer your question of “what temperature kills a car battery,” we’ve gathered multiple research sources around considerations when charging lithium-ion batteries in these extreme weather conditions. We will also look to provide some tips and tricks that support best charging practices in these weather conditions.

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What Temperature Kills a Car Battery and How Should I Charge in Winter Conditions?

Now that we’re in the midst of the holiday season and enjoying that cold weather, you may notice that your Tesla is taking a bit longer to charge and exhibiting a shorter range after charging for the same amount of time. So what’s going on? 

When attempting to charge your Tesla in extreme cold (near freezing temperatures), the onboard charging and monitoring systems will prohibit your Tesla battery from accepting a charge to prevent severe damage. 

Lithium-Ion batteries are built with an internal ionizing liquid that conducts electricity and supports the charging process. If this liquid is frozen or reaches near-freezing temperatures, the applied electrical current can severely damage or permanently kill the li-ion battery. So what are some ways to improve your charging strategy in extremely cold weather?

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Tips for Charging in Extreme Cold

• When you charge in extreme cold, your Tesla will use some of the energy drawn from your charger to warm the battery before charging. This means that charging times will be extended, or the same allotted charging time will result in a lower state of charge. Factor this in by scheduling earlier charging times.
• Leave your Tesla plugged in if you are charging your Tesla overnight in extreme cold. Your Tesla will monitor battery temperature and ensure the battery doesn’t reach near-freezing temperatures.

If you’d like to read up on some additional charging considerations for charging in the winter, check out our article: Tesla Extreme Weather Considerations - How To Optimize Your Tesla Driving For Winter Months

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Charging in Summer Conditions

On the other hand, we all know that Texas also has some extremely hot summers. It may seem like a distant memory at this point, but only six months ago, we were experiencing some record hot summers in Texas. 

So, as we dive into the new year, let's dig into some best practices for charging your Tesla in those hot Texas summers.

First and foremost, the most crucial consideration is to understand that your Tesla will automatically run your AC while charging if it reaches temperatures over 100 degrees Fahrenheit. This precautionary feature is intended to help keep your Tesla battery cool while charging in extremely hot conditions.

The challenge here is that it will take longer to charge your Tesla while the AC runs to help cool your Tesla cabin and battery since your AC consumes energy to cool down your Tesla. 

In some cases, Tesla users report experiencing challenges charging their Tesla to a target capacity when charging in extreme heat. 

Worse yet, by attempting to charge your Tesla to a target capacity while running your AC, you may end up just cycling the battery imposing unnecessary strain on your Tesla battery.

Tips For Charging In Extreme Heat

• Simple considerations, such as parking your Tesla in a parking garage or under a tree, can dramatically reduce the temperature of your Tesla’s cabin and battery and help improve charging efficiency.
• Utilize preconditioning, a feature that can cool your car before you enter it and get it ready for you to drive. If you would like to check out an easy way to set up preconditioning, there is an application that can help you. Optiwatt is a free app that allows you to schedule your charging for the cheapest price and help you precondition your car for any trip you may take.
• Consider dropping the target charge capacity to a lower, more achievable state of charge, such as 60% rather than 90%, if your driving needs allow it.

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Should I Leave My Tesla Plugged In All the Time?

It's wise to keep your Tesla plugged in as often as possible. Don't worry; your battery will retain a safe amount of heat.

Next Steps

Hopefully, with these points, you’re ready for charging in any condition. Heading for a ski vacation in New Mexico? Well, now you’re ready to charge in that freezing cold weather. 

Check out our other articles on Tesla charging strategies if you’d like to learn more. For our comprehensive guide to charging your Tesla check out The Comprehensive Guide to Maximizing your Tesla’s Battery Efficiency and Battery Life.