When to replace a car battery?

When should you replace your car battery?

Updated on 04/19/20
6 minute read


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In this article, I will share with you my take on when to replace your car battery. 

I have recently changed my car battery so I thought this is a great opportunity to share my take on when you should replace your car battery, tips, related topics and more.

So, when should I change my car battery?

The simple answer - when it is almost dead and you can not start your car anymore. 


There are a few things you can check before the battery is dead.

The idea is that we do not want to reach this "dead battery" situation. Especially when we are in a hurry and need the car to work well.  

It is not a secret that there is no good time for a battery to die. 


IF we want to control the point at which we need to change the car battery, without replacing a good car battery and waste our money, there are few courses of action.

  1. Take the car to the local electrician or auto repair shop and let them check the car battery and determine if we should change it. 
  2. check ourselves for various indications.

Before we decide, here are a few typical signs and easy tests that will help you understand if it is time to replace your car battery.

A quick disclaimer: I am no car batteries expert nor a certified electrician. All I share is from personal life experience. 


Signs that the car battery is dying

  1. External damage of any kind. 
    The battery seems damaged, its casing is cracked or there are bloating parts. 
  2. Corrosion around the posts.
  3. Car dashboard "battery" or "check engine" lights.
  4. Battery age. Read more in the car battery age section.
  5. Weak interior light when the engine is off.
  6. No cranck(starter), possibly with no electricity in the car interior. Also slow crank.
  7. intermittent starts. Works in the morning, but suddenly does not in the evening or the next day. 
  8. Voltage measurement. Since this process requires electricity know-how and also car mechanics at some level, I will skip the explanation about the process. This test is not a guarantee anyway so I don't recommend messing around with it unless you really know your way around the car. There are a lot of resources online that will teach you what and how to test, I leave it to you to decide if you want to go that way. 
  9. Leakage or bad smell (sulfur smell).
  10. The start-stop system won't initialize. You can read more about the start-stop system on Wikipedia. Each car brand has its own version.


If you experience either one of the signs above, it may be a sign of an old car battery that needs to be replaced.

Other possible reasons that may cause some of the signs above may include a faulty alternator, problems in the car computer, faulty electrical wiring, current leakage and more. 

If you decide to replace the battery yourself, notice that connecting a car battery in reversed polarity can possibly damage your car and battery. 

In any doubt, consult a professional electrician or a licensed mechanic.


What if your car battery is empty but still useful?

What if you left the light on and the battery is OK but drained?

Here how to recharge it. 


How to recharge a car battery

Sometimes, a car battery may still be usable but it got no juice left in it.

This can typically happen when:

  1. The car wasn't started for a while.
  2. lights left on.
  3. Using car power with engine off (when cleaning the car or outdoors).
  4. Momentary problems with the electrical system.
  5. more... 

In this case, you do not need to go and replace your car battery. You can recharge it and move on with your day. 

There are a few ways to charge your car battery.

Jump Starters

A good quality car battery jump starter may not completely charge your car's battery but it will be enough so the engine starts and the alternator can do the rest of the charging.

Jumpstarters come in various sizes, voltage and amps values. Make sure you buy the right one for you. 

Here is an example of a common jump starter on Amazon, fit for most car batteries. 


Solar charger

Solar chargers are great for emergencies or if you rely on your car battery when driving or traveling off-road or far from civilization.

Though maybe a little slow when it comes to charging, these solar chargers can really save the day if you are stuck with no battery in the middle of nowhere. 

You can find a verity of solar chargers on Amazon. Make sure you buy the one that fits your car battery, voltage, and output power.


Booster / Jump-start cables

Well, there is always the simple way of asking someone to start your car using good old jump-start cables and a second battery. 

The downside of this method is that you need that second car to help out. Not the best if there is only one car is involved.



Car battery age

Like all batteries, car battery also has a lifespan. 

Meaning, even if you store the battery and do not use it, it will still eventually become useless and will not store electricity. 

Why is this important?

One reason, it can be an indication that it is time to replace your car battery. If your battery is 3-4 years old, it means that it is maybe the time to replace it. Some brands can hold even more than that. It depends on the brand, the nature of usage and maintenance. 


Another reason is the age of a "new" battery you purchase.

If eventually, you decide to purchase a new car battery, regardless if you replace it yourself or at the auto shop, it is recommended that you check the age of the battery by examining the date imprinted on the battery itself. Typically stamped into the plastic cover. 

Here is an example:

Car battery age stamped into the plastic top cover.

Here you can see that the year is 2008, and the month is August, Or July, depends on where you are from.

I can't tell what is the exact redline for battery age. The newer the better. But my personal recommendation, if the battery age is greater than 6 months, do NOT buy it. 

In any doubt, consult a professional. 



There is no perfect point to change your car battery. Do it too early, and you waste money. Wait until your car will not start, you may experience inconvenience and pay more for car battery services.

Examine your car battery structural look, its age, the posts and that will help you decide when to replace it.

In any doubt, consult a professional.