Quite often, car batteries are taken for granted until they stop working. A dead battery can be an inconvenience at best and, at worst, may leave you stranded somewhere. That’s why it’s important to know when you should replace your car battery.
It’s important to look for warning signs long before the moment your battery is no longer strong enough to start the engine. In some cases, a dead battery can be caused by avoidable human errors, such as leaving the lights on and draining the battery overnight. In cases like this, you can get a jump-start to help start your car and recharge the battery. However, other problems can indicate that your battery is reaching the end of its useful life and that it might be time to replace it. Here are some warning signs that suggest it’s time for a new car battery.
How often to replace a car battery
One of the main indicators that you might want to replace your battery is age. On average, your car battery should last 3 to 5 years.  If it’s getting older, keep a close eye on how well it performs over time.
What causes a car battery to die
A battery can die as the result of poor battery performance, user error, or an electrical system malfunction. Below are some of the most common problems that will cause a battery to die. 
- Extreme temperatures both hot and cold can weaken your battery over time
- Leaving interior or exterior lights on will cause your battery to drain
- Poor or corroded battery connections can make it difficult or impossible for the charging system to continue to supply power
- A weak battery can drain easily, even as a result of minor use of electricity like the clock
- Parasitic drain can happen when a trunk light, glove compartment light or another device is left on
- A failed charging system can cause your battery to die while your car is moving; this can happen when the alternator isn’t working properly, and therefore fails to adequately charge the battery
Signs you might need a new car battery
Car has been sitting unused for a while
Battery life will vary based on numerous factors; much of that variance has to do with how often you drive your vehicle. Driving your car charges the battery. If you take your car out daily, the battery is probably going to last longer than the battery in a car that sits unused for long periods of time.
If you smell a sulfuric or “rotten-egg” odor emanating from your battery, there is a good chance that your battery has a problem, and you should seek out potential causes and remedies. 
Time it takes for the engine to start
If your car engine begins turning over more slowly when you start it, that’s a good indicator that your battery is beginning to fail. The lights on your dashboard might go dim or flicker when the car is starting, which is another indicator that your battery may be getting weak. 
Other signs that it might be time to replace your car battery
- The headlights dim when the car is idling, although they brighten up when you rev the engine
- You can see signs of corrosion at the battery terminals and cables
- Functions such as the power windows run very slowly when the engine is idling compared to their speed when the car is moving
- You repeatedly have to jump your car
If you notice these symptoms in your vehicle, it’s probably time for a new battery. You can always be sure by taking your car to an experienced mechanic, auto-supply store, or if you’re experienced working on cars, you can test it yourself. Testing the battery using a multimeter can help determine if the battery needs recharged or replaced. 
Maintaining a strong battery is one important component of car maintenance. Learn more about performing a check-up on your vehicle to ensure its systems are working efficiently.
 https://www.aaa.com/autorepair/articles/how-long-do-car-batteries-last, Accessed June 2022.
 https://www.firestonecompleteautocare.com/blog/batteries/things-that-drain-car-battery/, Accessed June 2022.
 https://www.autozone.com/diy/battery/how-long-should-a-car-battery-last, Accessed March 2022.
 https://www.aaa.com/autorepair/articles/when-to-replace-your-cars-battery, Accessed March 2022.
 https://shop.advanceautoparts.com/r/advice/car-maintenance/how-to-test-a-car-battery, Accessed June 2022.