If your car battery isn’t holding a charge, you may feel like you’re on thin ice. While this issue may be solved by a simple jump starter, more advanced problems require troubleshooting and more intensive repairs.
We understand how much your car means to you and how you need it to start and function reliably. Finding the root of the problem and learning how to fix the problem is probably at the top of your mind.
Keep reading to learn how your car’s charging system works and how you can isolate the issue. We outline the top reasons your car battery won’t hold a charge and what you need to do to fix the problem.
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Your Car’s Charging System
Your car battery may not be what rolls and makes your car move forward, but your car relies on it to receive the power needed to start the engine and power certain components. A dead battery cannot run key components such as you:
- Main relay
- Fuel pump
Spark plugs won’t get the spark needed to crank the engine.
In some cases, we mistake an issue with the charging system as a fault in the battery.
Your battery might be able to provide the voltage needed to power the vehicle, but without a functioning charging system (alternator, voltage regulator, and drive belt), it won’t recharge as you operate the vehicle.
It’s best to diagnose both issues using the same troubleshooting order to make sure nothing is overlooked.
What to Do First When Your Car Battery Won’t Hold Its Charge
When your car battery doesn’t seem to hold its charge, make sure you rule out human error first. Then do a physical inspection of your battery.
If you have a voltmeter or multimeter, you can test your battery at home. Otherwise, you’ll need to take it to a mechanic or auto parts store to test the battery.
1. Rule Out Human Error
The most common reason for a dead car battery is someone forgetting to turn off their lights. This may be your headlights, trunk light, or interior lights, but it will ultimately drain your car battery overnight.
Jump start your car and give it the chance to charge completely to make sure this wasn’t a one time issue.
2. Check Battery and Connections
Check your battery, battery terminals, and battery cables for any signs of damage.
For your battery, corrosion and a buildup of debris or grime can interfere with the ability to charge. Make sure you clean the battery regularly with a mild, approved cleaning method.
Your battery case should not be dented, cracked, or bulging. Physical damage can cause the cells inside to malfunction or die completely, interfering with your battery’s ability to hold a charge.
Make sure your cables are firmly connected to your positive terminal and negative terminal. Look for creases or frays along the cords.
3. Test Car Battery
If you have a voltmeter or multimeter, connect it to your battery to check the charge of the battery. A healthy battery should read 12.6 volts at rest and up to 14.6 volts while the engine runs (and it should spike while the engine runs).
Low voltage indicates the battery is not charged completely. If the voltage does not increase while running, you may have a bad alternator or other charging components.
A load test, which can be performed at a mechanic or most battery dealers and auto parts stores, reveals more comprehensive information regarding your battery health.
You connect your fully charged battery to a load tester. This simulates operating pressure your battery should hold up too. You need a new battery if your voltage drops below 12 volts.
Common Reasons for a Car Battery Not Holding a Charge (and Fixes)
If your car battery won’t hold charge and it isn’t one of the issues above, prepare for more in-depth testing.
At this point, the most common reasons a car battery won’t hold a charge include:
- Parasitic draining
- Improper charging times
- Operating conditions
- Issues in your charging system
In this section, we explain how to diagnose and resolve these issues.
1. Parasitic Draw (or Blown Fuses)
Parasitic draining usually happens when you have an accessory malfunction or a blown fuse. While your battery allows some mild parasite draining for radio memory or your alarm system, more significant draws will drain your battery completely.
This video explains how you can use a multimeter to not only check for a parasitic draw but use it to determine which electrical component is causing the issue. Once you repair or replace the part, your battery should be able to charge as normal.
2. Only Taking Short Trips
If you only use your car to take short trips to and from the store, you’re probably not allowing the battery charger system enough time to replenish the power lost.
Most people don’t run into this problem, but it can happen if you find yourself only running short errands. If you suspect this is the issue, allow your vehicle to run long enough to charge the battery completely and see if the car battery keeps its charge.
If this is a common occurrence, you may need an external charger to maintain your battery. You can also plan some longer trips to offset the issue.
Keep in mind that cold water will discharge your battery faster than hot weather. If you’re experiencing issues in the winter, the temperature may be to blame.
Ultimately, your car should be able to at least start and maintain enough power. This usually happens in conjunction with an aged, defective, or dying battery.
4. Charging System Issues
If your car battery won’t hold a charge while driving, it usually means your charging system is at fault. These parts run in a circuit to provide power to recharge the battery: your alternator belt generates mechanical energy for your alternator to turn into electrical energy that is then regulated before charging the battery.
Check these parts for signs of visual damage (especially your belt, which can become obviously worn over time). You can also use an ammeter or multimeter to diagnose issues with your alternator and decide if you need a replacement.
Any issue with your car battery or charging system requires immediate attention. There is too much risk to your entire electrical system, even with a minor issue, to excuse running the vehicle while the issue persists.
Run through these troubleshooting steps to find the root of the problem, but do not hesitate to hand the project over to a mechanic if needed. Most electrical problems are simple to fix, but failing to do so tends to snowball into a bigger problem.
Is your car battery struggling to hold a charge? Drop your symptoms in the comments for help diagnosing the issue.