Car Won't Start With New Battery? 10 Potential Causes

  • November 13, 2023
Checking your car battery Checking your car battery

Is your brand-new car battery dead? While this is a frustrating experience, the silver lining is that this may be an easy issue to resolve. Read on to discover why your car may have electrical problems after replacing the car battery and what you can do to fix this problem.

Why Won't My Car Start with a New Battery?

1. Incorrect Battery

Before jumping to any major conclusions, you'll first want to verify if your new battery meets your car's size and power requirements. Car batteries aren't universal, so it's crucial to check your vehicle's owner's manual to confirm you've installed a suitable battery.

If you installed the correct battery size and type, other installation issues could be at play. 

2. Improperly Installed Battery

If your car won't start after installing a new battery, the issue may be as simple as poor installation. Make sure the battery cables are attached with the correct polarity. Reversing the polarity can cause a current surge in the opposite direction and damage the fuses, fusible links, relays, engine control module, and other major computers in the vehicle. So, always attach the red, positive cable to the positive terminal ("+") and the black, negative cable to the negative battery terminal ("-"). 

3. Corroded Battery Cable Clamps

Another common issue that may be preventing the engine from starting is not cleaning the corrosion from the battery cable clamps. While your battery is new, the old one may have accumulated enough corrosion on the clamps to prevent electrical flow. If there is corrosion, clean it using a toothbrush and a homemade cleaner, or purchase battery terminal cleaner and a wire brush from your local parts supplier. Ensure the cable connectors and the battery terminals fit snugly so they don't get loose from driving vibrations.

4. Accidentally Leaving the Lights On

If you accidentally leave the interior lights or headlights on during the night or a long parking break, your battery can drain completely. As a result, the battery won't have enough juice to run the starter. Starting the engine requires an extreme amount of short-burst energy from the battery, so your car may be unable to start even if the battery isn't completely dead.

One way to recharge your empty battery is to jumpstart it. Read our guide on the right way to jumpstart a dead battery to learn how to do this properly. After jumpstarting your car, hit the road for about 30 minutes to let the alternator charge the battery.

5. Parasitic Draw

Your battery continues to power low-current devices after you turn off your car. So, the alarm system, clock, and similar low-power devices keep working. However, the battery can quickly become drained if something has a major impact on it. This could be due to a short circuit, a wiring issue, a stuck relay, or even everyday accessories like your smartphone. 

If your battery keeps dying, even if you are sure no lights were left on and no accessories are plugged in, you may be dealing with parasitic draw. Common signs of a parasitic draw are frequent jump-starts, slow cranking, dimming headlights and dashboard lights, and frequent battery replacements. 

It can be tricky to diagnose which component causes the problem. So, if you suspect a parasitic draw, schedule an appointment at your local Firestone Complete Auto Care, and our expert technicians will trace the circuit to pinpoint the issue.

6. Bad Starter

While your battery provides the power to start the engine, it's actually the starter that does all the initial heavy lifting. A bad starter is among the top reasons for car starting issues, regardless of the battery condition. 

Your battery powers the starter motor, which allows the engine to turn and begin the ignition process. Once the fuel and air are mixed in the engine and ignited, the alternator starts meeting the vehicle's electrical needs. But your engine can't start if something is wrong with the starter, even if the battery provides sufficient energy.

Two major signs of a bad starter are illuminated dashboard lights even though the car won't start and a clicking noise when trying to turn the engine on. If your electrical system works, your battery probably has a good charge. But your starter may need to be fixed if you hear a clicking, whirring, or grinding noise when trying to start the car. 

7. Blown Fuse or Relay

If your starter fuse or relay is blown, you likely won't be able to start your car. Fuses are designed to blow if there is a sudden electrical power surge. This prevents damage to much more expensive car parts. 

If you accidentally installed your new battery with the wrong polarity, the fuses will likely blow. But, a blown fuse could also signal other electrical issues that should be resolved immediately.

8. Alternator Issues

Your alternator is an essential part of the vehicle's charging system. It charges the battery using the engine's rotational power and provides the necessary electricity for various systems in your car. But, if something is wrong with the alternator, your battery may not be charged enough to start your vehicle. 

A faulty alternator won't sufficiently recharge your battery after the initial engine start. Likewise, if the alternator belt is worn and slipping, the alternator won't get the necessary power to charge the battery. This problem may also be exacerbated if you frequently take short trips. Short trips and alternator issues combined will quickly deplete the battery.

Some signs of a bad alternator are seeing a warning battery dashboard light, growling or whining noises under the hood, engine stalling, malfunctioning accessories, irregular battery voltage, and dim or overly bright lights. 

9. Seized Engine

If you don't change your oil on time, your engine may be running with extremely low oil levels. This  could lead to an engine seize. As a result, your car won't be able to start, resembling a dead battery. Insufficient oil levels can lead to various issues, including engine overheating and engine seizing. 

However, encountering a seized engine without early indication is very rare. If you skipped changing your oil and have recently heard knocking sounds and noticed a burning oil smell, your engine may be seized. Likewise, if you've experienced a drop in performance or engine overheating, the reason why your car won't start may be engine-related.

10. Defective Battery

While it's extremely rare, your new battery may be defective. You can easily inspect the battery quality with a multimeter to see if the output voltage matches its label. Likewise, visually inspect the battery for dents, cracks, or swelling. 

"But, do you have to jump a new battery? Maybe they are sold empty?" — No. Brand-new car batteries don't require jumpstarting. So, if the multimeter shows an excessively low voltage, your new battery may be defective.

If you suspect something is wrong with your battery, visit your local Firestone Complete Auto Care center, and our technicians will do a full inspection for you. On top of free battery testing, our expert technicians can also find the perfect battery replacement for your vehicle, budget, and driving style. 

Our technicians install DieHard batteries that come in several models, each with their own specific benefits. All DieHard batteries carry a limited warranty, plus the extra benefit of 24-month/24,000-mile DieHard Assurance coverage*.  

Firestone Complete Auto Care is Here to Help 

Still trying to pinpoint the problem? This issue may be best left up to the professionals. Stop by a Firestone Complete Auto Care location near you; our knowledgeable technicians can help diagnose and resolve the problem. Whether it's an electrical problem, battery issue, or something else entirely, we've got you covered.

*Please refer to for full details, terms and conditions of the limited warranty and coverage.

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