Car Battery Won’t Charge Past 80?

The first thing to check when your car battery won’t charge past 80 is the alternator. If your car isn’t charging at all, then it’s likely that the alternator isn’t working properly. The alternator is what converts mechanical energy into electrical energy, which is then used to charge your battery.

If your car charges only to 80%, or if it charges intermittently, chances are good that you have a loose connection somewhere in the charging system. This can be caused by corrosion or by something as simple as a loose screw. Make sure to check your connections thoroughly before taking any further action, because if one of them is loose, it could cause damage to other parts of your vehicle.

What causes a car battery to fail?

The most common cause of a car battery failing is simply old age. If you’ve had your battery in the car for more than four years, it’s likely that it needs to be replaced. However, there are other reasons why a car battery won’t charge past 80 percent.

If there’s an electrical short in your car or if you have a bad alternator or voltage regulator, that can cause your battery to fail to charge properly. But even if you’re not sure what’s causing your battery to fail, you can always get it tested by a professional mechanic.

How can you tell if your car battery is failing?

The first sign that your battery might be failing is when it won’t charge past 80%. If you’re noticing this, check your alternator by asking a mechanic to test it. The alternator is responsible for keeping your vehicle’s battery charged, so if it’s not working properly, it could be the cause of your problems.

Another way to tell if your car battery is failing is to make sure that there isn’t any corrosion on the posts and terminals. Corrosion can cause a loss in power, which can make it difficult for your car to start up or run smoothly. To clean off corrosion from your battery posts and terminals, you’ll need some baking soda, water, and an old toothbrush.

If you’ve tried everything above and your car still isn’t running properly, then it might be time to replace the battery altogether.

How do you check the health of your car battery?

You can test the health of your car battery at home with a battery tester. First, you’ll need to get all of the electrical items in your car turned off. Then, connect the negative terminal from your battery tester to the negative terminal on your car battery. Connect the positive terminal from the tester to the positive terminal on your car battery. If there is voltage present in this circuit, then your battery is working fine and does not need to be replaced yet.

Make sure that the battery terminals are clean

The first thing you should do is check the battery terminals. If they’re corroded or dirty, clean them with a wire brush and some baking soda. If they’re still corroded after cleaning, take a look at the posts that hold the battery cables to see if they’re rusted or bent. You can use an adjustable wrench to loosen and remove them if necessary, but be sure not to damage any wires underneath.

Check the car’s charging system

Check your charging system. The charging system is responsible for sending power from the alternator to your battery. If this tube is damaged or broken, it will not be able to send energy to the battery and you will have a low charge level on your car’s battery.


The car battery won’t charge past 80, and the owner is not sure what to do. The owner has checked the alternator, and it seems to be working fine, but the battery still won’t charge. The owner thinks that this might be a problem with the computer system in the car, but he’s not sure how he would go about fixing it.

Steven Hatman
Steven Hatman

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