Reasons Why Car Batteries Fail in Winter

Your car battery is the heart of your car’s electrical system. It gives your engine the power to start, turn the lights on, and keep things like that radio and windows working. But starting the engine is its biggest job – and the one that becomes a challenge when it's freezing.  

How Long Does a Car Battery Last in the Cold?

Car batteries work through a chemical reaction. Inside each battery are cells filled with an electrolyte solution (a mixture of water and sulfuric acid) and lead plates. When you turn on your car, a chemical reaction between the lead plates and the electrolyte produces electricity. That electricity powers the starter motor, which gets the engine running.

Here’s the problem: chemical reactions slow down in the cold. Just like your body may feel sluggish on a cold morning, your car battery is also less energetic. As temperatures drop, the electrolyte thickens, and the reaction slows down. This means:

• The battery produces less current (electricity),
• It takes more energy to start the engine (because cold oil thickens and increases engine resistance),
• And your battery becomes less efficient overall.

The average battery lifespan varies between 3 to 5 years, but the colder it is, the harder it becomes for the battery to do its job. And to make things worse, your engine actually needs more power to start in the cold because the oil inside thickens. It’s like trying to start your car while it’s swimming through syrup.

So now you’ve got a battery that’s feeling sluggish and an engine that’s asking for more power than usual. Not exactly a winning combo.

Consider the Additional Load 

1. Increased Power Demand: Winter means more use of heated seats, window defrosters, headlights, and heaters — all of which pull power from the battery. 
    
2. Short Trips and Stop–Start Driving: Cold weather exacerbates an already common issue: frequent short trips. Starting the car draws a lot of power and energy from the battery. Over time, this will lead to a weaker battery until it eventually fails. 
    
3. Old or Worn Batteries: A battery that’s already a few years old is more vulnerable in winter. Most car batteries last between 3 to 5 years/ If you are on the older side, it may not hold a charge as well. Combine that with cold weather, and you might have a problem getting anywhere, nevermind starting. 

Signs Your Car Battery is Struggling 

Here’s what to watch out for:

• Your engine is cranking slowly when you start the car.
• The lights inside your car or your headlights are dim.
• You hear a fast clicking sound when trying to start the engine.
• Your dashboard battery warning light comes on.
• Your windows or radio are acting weird. 

What to Do If Your Battery Dies

If your battery fails to work, here’s what you can try (depending on where you are):

Start by attempting to jump-start using jumper cables and another vehicle. Make sure both cars are turned off before connecting the cables. Once it's running, drive for at least 15-30 minutes to help the alternator recharge the battery. However, If it doesn’t hold the charge or is unable to retain power, it may be time for a replacement. 

Another way you can try is If you’re unable to jump-start the car or  you're stranded somewhere, don’t take unnecessary risks. Depending on your motor plan and provider, you may be able to call for roadside assistance, request a jump-start, or arrange a professional tow. 

If you ever need extra support, MotorHappy offers additional service benefits – like roadside assistance – included with each Service Plan and Maintenance Plan. 

How to Care for Your Battery During Winter 

A few simple habits that you can use to protect your car’s battery will go a long way. We’ve compiled some tips – with the help the Automobile Association South Africa (AASA) – to help you avoid those cold morning surprises: 

Power Down Properly

Before you dash inside, take a second to double-check that everything in your car is switched off. That means headlights, cabin lights, and even the radio. Make sure the doors are properly closed too, or you might leave interior lights running without realising it. 

Keep an Eye Out for Corrosion or Loose Cables

Pop the bonnet now and then and take a look at your battery. If you see a chalky white or greenish build-up around the terminals, that’s corrosion – it’s not great for your battery’s performance. It messes with the connection between the battery and your car, which means less power gets through. Also, make sure the cables are snug and not wiggling around. Loose connections may lead to weak starts. 

Don’t Skip on Regular Car Maintenance

The best way to avoid a flat battery in winter? Regular car maintenance. Most car batteries last around 3 to 5 years, but they should be tested once they’ve reached the 4-year mark. If you’re unsure of how old yours is, a quick visit to a battery shop or mechanic can clear things up. And honestly, don’t try to stretch a dying battery through another season. It’s just not worth the stress when it suddenly gives out.

Store it Properly and Keep it Moving 

If you’re not driving everyday, winter temperatures can still affect your battery. Try to park your car in a garage or covered space when you can. Plus, don’t let your car sit still for too long. Even if you’re not going anywhere, start it up and go for a short drive every few days. Moving the car helps keep the battery charged. 

The Bottom Line 

Whether you’re experiencing car trouble at home, at work, or even at the gym, the most important thing is to evaluate your situation. The tips provided here are designed to give you a bit more confidence and support when things don’t go as planned. You should at least be prepared.

From your car battery to basic maintenance, regular upkeep is essential. We also want to remind you that parking in a sheltered space helps, and checking your battery every now and then is key to maintaining reliable performance.