Are you having trouble with your car battery? Is it dying on you all the time? If so, then this blog post is for you! 

We’ll discuss some common causes of a dying car battery and provide some tips to help prevent it from happening again.

Loose or Corroded Battery Connections

One of the major causes of car batteries dying is loose or corroded battery connections. This can impede the battery’s ability to transmit power and prevent the car from starting. Corroded or loose connections can also damage the battery and drain it. 

To prevent this from happening, check your battery cables often for corrosion and clean them with a wire brush if necessary. By doing this, you can make sure that your battery has all the power it needs to start your car and keep it running.

Parasitic Draw

The next cause of why your car battery keeps dying could be due to parasitic draw. This occurs when something in your car is still drawing power even when the car is turned off. This could be a faulty relay, a headlight/dome-light switch, an alternator, or any other electrical gremlins.

Electric cars can suffer battery drain because of extreme temperatures, damaged batteries, and parasitic drains, just like conventional cars. Finding and fixing the issue is the best way to ensure that your car battery stays healthy and functions properly.

Taking your car to a mechanic with an electrical diagnosis machine can help you identify which component is causing the parasitic draw, and then you can get it fixed.

Accidental Discharge

Accidental discharge is a common reason why car batteries keep dying. When a battery is discharged, it means that the electrical current being generated is not sufficient to power the vehicle. 

This can be caused by leaving electrical devices or lights turned on, or as a result of something more serious like a defective charging system or alternator.

 In any case, it’s important to check for any signs of electrical issues before attempting to jump-start your car.

Multiple Short Trips

If you’re driving your car often on short trips, this can contribute to a shorter battery life and a battery failing to keep its charge. It takes twenty minutes of charging for a battery to fully recover from starting the engine. 

If you consistently only take short trips that don’t allow full charging, then the alternator won’t have enough time to properly charge the battery. This will eventually shorten the overall lifespan of your battery, so it’s best to try and avoid multiple short trips if possible.

 Additionally, keeping an eye on the cables and posts for any corrosion can help prevent issues in the future.


Failed Diode in the Alternator

I’ve already gone through some of the likely causes behind why your car battery keeps dying so quickly, but one factor that can be overlooked is a failed diode in the alternator.

This issue can be hard to detect, as it causes a closed circuit that continues to draw power even when the engine is turned off. As a result, this continuous drain can quickly deplete your battery’s charge and make it difficult to start your vehicle. 

If you suspect this might be at play, I suggest having an experienced technician inspect your alternator for any faulty diodes or other issues.

Dead Battery Cell

It’s important to check the battery cells to make sure they’re all working properly. 

A dead cell can cause your car battery to die suddenly and unexpectedly. This is usually caused by a deep discharge or by sulfation, which can happen if the battery has not been used for a long period of time. If one or more of your cells are dead, you’ll need to replace your car battery entirely.

Temperature Issues

Temperature can also play a role in why your car battery keeps dying. 

High temperatures can evaporate the vital liquids of your battery and weaken its charge, as well as speed up corrosion. Cold temperatures can reduce the electrolyte solution’s ability to conduct electricity, and the heat of summer can accelerate battery failure. 

New batteries are more resistant to extreme temperatures, but even if it takes extremely low temperatures to cause the battery to freeze, it is still important to be aware of the issue.

Faulty Alternator

One of the most common causes of a car battery dying is a faulty alternator.

The alternator is responsible for recharging the battery after it has been discharged by the vehicle’s electronics. A failing alternator will have trouble charging the battery and, in turn, the car battery won’t have enough power to start the vehicle. 

If you suspect that your alternator is going bad, it is important to take your car in for a check-up as soon as possible. You can check the car’s dashboard to see if the alternator is charging, but if the alternator has a failed diode, it will still create a closed circuit that drains your battery even when the engine is off. 


The 2nd last issue that can cause your car battery to keep dying is overcharging.

Overcharging your battery can be caused by human error, such as failing to comprehend how to use a car battery charger or choosing the incorrect voltage. 

This can lead to excessive heat buildup and electrolyte evaporation, which will cause the lead plates in the battery to corrode and ultimately shorten the lifespan of the battery. 

Additionally, overcharging can lead to sulfation, which occurs when lead sulfate accumulates on the lead plates following a recharge. If left unchecked, sulfation can reduce the amount of energy your battery produces and eventually cause it to fail. 

To avoid overcharging, make sure you’re using the right charger for your car and that you’re not leaving it plugged in for too long.

Lack of Care for Your EV

It’s not just about overcharging or temperature issues, though. Taking proper care of your electric vehicle’s battery is important to ensure it lasts as long as possible.

This might include avoiding long periods of time without charging and making sure to charge it regularly and to the right levels.

Range anxiety is real, and it’s easy to forget to charge your car when you don’t need it. But regular charging and proper maintenance can help reduce its impact and keep your battery healthy for longer.

Chris Miller

Chris Miller is an auto journalist who specializes in reviewing new cars and providing helpful advice on family vehicles. He has a passion for cars and enjoys sharing his knowledge and expertise with others.

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