No one wants to be stranded, anywhere, ever, whether you are in your driveway, at work, or on vacation. So, with that being said, YES, you should absolutely replace your car battery before it dies.
There is nothing wrong with being a little proactive and replacing your car battery before you find yourself stuck somewhere. The trick is to know when to replace that battery. You paid good money for that car battery and you want to get as much life out of it as you can.
At What Percentage Should a Car Battery Be Replaced?
Car batteries are not typically measured in percentage like electronic device batteries. Instead, they are measured by voltage. Car batteries need a certain amount of voltage to start the car and power the electrical systems. A fully charged car battery should read between 12.6 and 12.8 volts. However, as the battery ages, the voltage decreases. Once the voltage falls below 12.4 volts, the battery is considered weak and may need to be replaced soon.
To measure the voltage of your car battery, you can use a voltmeter or multimeter. Here are the steps you need to follow:
- Turn off your car’s engine and remove the keys.
- Set the voltmeter to read DC voltage and choose a range that covers at least 15 volts.
- Connect the positive (red) lead of the voltmeter to the positive terminal of the battery and the negative (black) lead to the negative terminal of the battery.
- Read the voltage on the voltmeter display. If it is between 12.6 and 12.8 volts, your battery is fully charged. If it is lower than 12.4 volts, the battery is weak and should be replaced soon.
Proactively replacing a weak or old car battery can help avoid the inconvenience of a dead battery, but how long can you expect a new battery to last?
How Long Should a Car Battery Last?
As we discussed in our article ‘How Long Should Car Batteries Last? 5 Ways to tell if it should be replaced‘; we established that the average car battery lasts between three and five years, although some batteries may last up to six or seven years although this is very rare. The lifespan of a car battery depends on several factors, including:
- -The type of battery (flooded lead-acid, sealed lead-acid, gel lead-acid, or AGM lead-acid)
- -The climate (hotter climates shorten battery life while cooler climates extend it)
- -How often the car is driven (batteries last longer when they’re used regularly)
- -How well the car is maintained (regular oil changes and tune-ups prolong battery life)
With proper care and maintenance, most car batteries will last between four and six years.
Should I Replace My Battery After 4 Years?
There are many signs that indicate that your car battery is about to die. So how do you know when it’s time to replace your battery? There are several dead giveaways to look for that indicate your battery is dying:
- -Slow engine cranking
- – dim headlights
- – electrical problems (e.g., power windows or seats that stop working)
- – check engine light is on
If you notice any of these symptoms, it’s time to get your battery tested. Many auto parts stores offer free testing and will even install a new battery for you if necessary.
Should you replace your car battery after four years? Well, not necessarily, but you should keep an eye out for the above mentioned signs of a bad battery.
While most car batteries will last between four and six years, the exact lifespan of your battery will depend on several factors such as the type of battery, climate, how often the car is driven and how well the car is maintained.
Therefore, it’s essential to regularly check your battery for signs that it might be dying (e.g., slow engine cranking, dim headlights, electrical problems). If you notice any of these symptoms, it’s a good idea to get your battery tested by a professional and consider replacing it if necessary.
How Do I Check the Health of My Car Battery?
To know if your car battery is weak, look for the following signs: slow engine cranking when you start your car, dim headlights, electrical problems (e.g., power windows or seats that stop working), and a check engine light that is on. You can also use a voltmeter or multimeter to accurately measure the battery’s state of charge and activity level. Most automotive shops offer free battery testing and will even install a new battery for you if necessary.

Automotive shops use a voltmeter to measure your battery. It’s a fairly simple tool to use, if you wanted to perform the test yourself.
-Connect the negative lead of the voltmeter to the negative terminal (-) on your car battery.
-Connect the positive lead of the voltmeter to the positive terminal (+) on your battery.
-Turn the dial on your voltmeter to register a DC voltage in a range approximately equal to or slightly higher than that of your battery.
-Read the digital display and record the voltage.
-If it is higher than 12.6 volts, this means that your car battery is healthy and charged; if it is lower than 12.4 volts, this means that your car battery is weak and needs replacing.
How Do You Know If It’s the Alternator or the Battery?
I answer this question in more depth here: Bad Car Battery Vs. Alternator-4 Signs to Tell the Difference. But if you are looking for the abridged version continue reading.
To determine if your car’s battery or alternator is the culprit of your electrical problems, you can get a quick answer by checking the battery indicator light on your dashboard. If the light comes on while you are driving, it usually means the battery is the issue.
If the light only comes on when you’re idling and goes off again when you speed up, this often indicates that it’s the alternator. However, there are several other signs to look for that can help you confirm which part is failing.
- If your car won’t start, it is usually a sign that the battery is dead or dying.
- A clicking sound when you turn the key is another sign of battery failure.
- A dimming dashboard light indicates the alternator is not charging correctly.
- Electrical accessories not working correctly (e.g., power windows or air conditioning) can be caused by either a failing battery or alternator.
- If your car stalls while driving or your headlights are very dim, this often indicates that the alternator is failing.
In summary, it can be difficult to determine if your car’s electrical problem is due to a battery or alternator issue. However, by paying attention to these common signs, you can make an educated guess as to which part is failing and take steps to address it appropriately.
Final Thoughts…
It can be difficult to determine whether your car’s electrical problem is due to a weak battery or an alternator issue. However, by paying attention to the common signs like slow engine cranking when you start your car, dim headlights, and other electrical issues that may arise in the form of power windows or air conditioning not working correctly – it should become easier for you to make an educated guess as to which part is failing.
Regularly checking your battery for any signs that it might be dying will help prolong its lifespan and save you from potentially costly repairs down the line. So don’t hesitate – get out there and check those batteries!
Safe travels…