Car Won’t Start With a New Battery? Common Causes & Solutions

Once again, your car isn’t starting—even though you just replaced the battery!

Learn how to get to the root of the problem as well as common issues and how to fix them.

Diagnosis: Car Won’t Start After You Replacing the Battery

You replaced your car’s battery with suspicion that was the problem, but that didn’t solve it.

You’re not alone.

Follow the below steps to diagnose and fix the issue.

The most common causes of a car not starting with a new battery have to do with installation, the alternator, or the starter.

Keep reading to learn how you can check each.

If you’re not experienced with replacing and testing car batteries, it is best to consult a professional mechanic.

1. Check the Battery

The first thing you should check is whether or not the battery has been installed correctly.

Look at the connections to ensure they are all intact.

They should be tight enough that they won’t move when you shake the battery terminal.

If they do move, re-torque them. 

Installing the battery cables to the wrong posts is another common mistake.

Check to see if the positive cables are connected to positive posts, and negative cables to negative posts.

If these have been switched up, and a positive is connected to a negative, you’ve likely reversed the polarity.

Doing this causes damage to your alternator, which shorts your battery.

When this happens, the wire melts and blows one or more fuses. 

2. Check the Alternator

If you can get your car running, the next part of your car you’ll want to check out is the alternator.

Your battery may be brand new, but the alternator is unable to charge it.

If you new car battery dies while driving, the alternator is a likely suspect.

There is commonly given bad advice on how to do this, so it’s time to set the record straight.

IMPORTANT: Do not unplug the positive connection while your car is running. This can damage the electronics.

Instead, use a voltmeter to test the alternator while your car is running.

If the battery is fully charged, you’ll see the voltage shoot up upon running the engine.

If the voltage stays steady or gets lower, your alternator likely needs to be replaced. 

3, Test the Starter

If your interior lights and accessories are functioning, but you can’t get the car to run, it’s time to check out the starter.

If your car makes one click sound and doesn’t turn over, this is likely the issue.

Because a bad starter mimics a dead battery, people commonly replace their battery when the starter was the issue all along.

This diagnosis is a bit trickier because there are several parts of the starter that can malfunction. It’s recommended that you remove it from your car and bring it to a local automotive store. Many locations will run a free test on your starter to see if it works or not.

Other Possible Causes of Your Car Not Starting With a New Battery

Did you follow the steps above, yet the battery, alternator, and starter seem to be functioning properly?

Below are further possible causes your car isn’t starting. 

The Connectors are Corroded

Another possible issue that prevents your car from starting is corrosion on the connectors.

PRO TIP: If you see corrosion, remove it with a mixture of baking soda and water.

Add baking soda to COLD water until you have created a thick paste. It’s important to avoid hot water, as this can erode steel.

This should only be done when everything is OFF and disconnected.

Parasitic Draw

If you have a brand new battery that dies after your car has been parked for a short amount of time—a few hours or days—your car could have a parasitic draw.

This occurs when an electrical part of the car continues drawing power when it shouldn’t.

Diagnosis of this issue requires special knowledge because circuits need to be traced in order to identify the root problem.

Other possible problems include issues with your car’s transmission, fuse, ignition, spark plugs, or fuel pump.

If you’re struggling to diagnose the issue, seek professional help from a mechanic.