A fully charged car battery is crucial for the proper functioning of any vehicle. However, if a car battery is unable to charge beyond 75%, it can be a significant cause of concern. I will discuss the potential reasons for this issue and offer in-depth solutions to address it.
1. A bad alternator
One possible cause of a car battery that won’t charge past 75% is an issue with the alternator. The alternator is responsible for generating electricity to charge the battery while the engine is running.
A malfunctioning alternator can impede its ability to charge the battery fully. This can occur due to various reasons, such as a defective alternator, a damaged belt driving the alternator, or a malfunctioning voltage regulator.
2. Faulty/worn battery
Another possible cause is a problem with the battery itself. Over time, car batteries may become damaged or worn out, reducing their capacity to hold a charge.
This can happen due to factors such as age, exposure to extreme temperatures or excessive use of electrical systems with the engine turned off.
A third potential cause of a car battery that won’t charge past 75% is an issue with the charging system. The charging system is responsible for transferring electricity from the alternator to the battery.
3. Issues with the charging systems
If there is a problem with the charging system, it may not be able to provide enough electricity to charge the battery fully. This can be caused by problems such as a faulty charging system, a damaged wiring harness, or an issue with the battery terminals.
To address these issues, it is essential to take the following steps:
- Check the alternator at a professional mechanic to diagnose and repair or replace it if necessary.
- Replace the battery with a new one that is suitable for the specific make and model of the vehicle.
- Have the charging system checked by a mechanic to diagnose and repair or replace any faulty components.
Ensure that the battery terminals are clean and tight. Loose or corroded terminals can prevent the battery from charging correctly. Clean them with a wire brush or a baking soda and water solution, and use a wrench to ensure they are tight.
Costs of repairs
The cost of repairs and labor for the causes of a car battery that won’t charge enough can vary greatly depending on the specific issue and the make and model of the vehicle. Below is an approximate range of costs for each of the causes discussed in the previous article:
Alternator repair or replacement: The cost of alternator repair or replacement can range from $300 to $800, including labor costs. The cost will depend on the make and model of the vehicle, as well as the extent of the damage.
Battery replacement: The cost of a new battery can range from $50 to $200, depending on the type and size of the battery. Installation costs for a new battery can range from $50 to $100.
Charging system repair: The cost of repairing the charging system can vary widely depending on the specific issue and the make and model of the vehicle. It can range from $200 to $800, including labor costs.
Cleaning or replacing battery terminals: The cost of cleaning or replacing battery terminals is relatively low, usually around $50 to $100.
It’s worth noting that the above costs are approximate and subject to change depending on location and the make and model of the vehicle.
It’s always a good idea to get a detailed estimate from a professional mechanic before proceeding with any repairs.
It is important to keep in mind that it is always recommended to consult a professional mechanic for an accurate diagnosis and repair estimate.
They will be able to give you a more detailed and accurate cost of repairs and labor for the specific issue you are facing with your car battery.
At what percentage should the battery be replaced?
Most car batteries are considered “dead” or in need of replacement when they fall below 12.4 volts or 75% of their full charge. At this point, the battery may not have enough power to start the engine, and it may not be able to hold a charge.
So, if yours has a maximum charge percentage of 75 you’re on that limit and it’s required to buy a new battery.
It’s worth noting that the lifespan of a car battery can vary depending on factors such as usage, climate, and maintenance. In general, a car battery can last between 3 to 5 years.
However, in some cases, it may need to be replaced sooner if it is frequently used in extreme temperatures, or if it is not maintained properly
A battery that has issues with charging will cause other related problems. It’s advisable to check the main reasons and fix them to avoid other costly repairs.