The car battery is perhaps the most important component of your car. You need a strong battery to operate all the electronic parts your vehicle has. A weak battery means you will struggle to start the car, especially in harsh weather. Not to mention, the headlights will be too dim, causing you considerable trouble while driving at night. Therefore, you must know how to test car battery at home. It will help you maintain your battery and keep it in a fully functional condition.
How to Test a Battery at Home
There are many ways to check the car battery yourself. However, we are going to discuss the 9 most common and easiest of these methods.
The following video also explains how to check car battery at home.
1. Check with Voltmeter
You can check the voltage of electronic devices with the voltmeter. Depending on your budget and preference, you can choose from a digital or analog voltmeter. You must switch off all the car accessories that use electricity before using the voltmeter. Some of these components included headlights, radio, and ignition.
The next step is to connect voltmeter points to the battery terminals. You should always connect the positive point to the red terminal and the negative point to the black terminal on the battery. Most car batteries have a voltage of 12V. Therefore, any reading between 12.4V and 12.7V indicates a good battery.
Your battery is 75% charged if the reading is at 12.3V. Similarly, it is fully charged if the reading is above 12.5V. The battery is only 25% charged and has a very low voltage if you get the reading of fewer than 11.8 volts.
2. Battery Health Indicator
Most modern batteries come with a battery health indicator. You may have already used it as a car battery check. The indicator consists of an arrow that moves over a red and green bar. Your battery has sufficient voltage if the arrow is on the green part. If it turns red, the voltage is on the lower side. The arrow will turn black if the battery is empty.
3. Headlight Test
How to test your car battery if you don’t have a voltmeter and battery health indicator? You can always check how the headlights behave when you start the car. The battery may be low in voltage if the headlights are darker than usual. Brighter than normal headlights mean the alternator is not providing enough current to the battery and thus, it cannot fully charge.
The battery is functioning properly if the headlights are as bright as they normally are.
4. Load Test
A load test is another common method used for car battery testing. What you need is a real carbon pile load to complete this test. The battery should hold 9.6 volts for 15 seconds if you check it with a CCA rating of one and a half. Don’t forget to fully charge the battery before performing this test.
Watch the video to learn how to test a car battery using load test.
5. Check with Ammeter
If you want to check the battery’s incoming and outgoing charge, you must use an ammeter. It will help you find the amount of the charge coming in and going out of the battery. The car battery is good if it is receiving full incoming charge.
Here is how to check current or amperes of a car battery.
6. Power Probe
You can also use a power probe to test a car battery if you don’t have a voltmeter. The power probe also comes with a tip that you can place on the positive and negative battery poles. If you get the reading between 12.2 volts and 12.9 volts, your battery is working properly.
7. What about Clicking?
You hear a buoyant roar every time you start your car. The roar gradually settles into a purr, indicating a properly working battery. On the other hand, the battery is dead if all you hear is a series of “clicks.” A single click may means problem with a car battery jump starter. However, most people consider these clicks as a final indicator that it is time to replace the battery. You must consider visiting a good mechanic as soon as you start hearing these clicks.
8. Hydrometer Check
You can check how much acid is in the battery plates using the hydrometer. The battery is in good condition if the acid is in low quantity. A hydrometer with a thermometer always gives you the best results. Some hydrometers also have conversion tables while others automatically adjust themselves.
Make sure to wear gloves while using hydrometer because battery acid is a hazardous material. Similarly, a metal thermometer can react with the acid, and therefore, you should not use it for checking the temperature of electrolytes.
How to Test Car Battery at Home with Hydrometer?
First of all, remove the top battery covers. Now, drop the hydrometer in every cell of the battery one by one and measure the electrolyte’s specific gravity. A good battery gives the reading between 1.265 and 1.299 for every cell. Your battery is uncharged if the reading falls below this range. You have a sulfated battery if the discrepancies in the cell’s values are too large.
9. Physically Inspect the Battery
You can also detect any cracks and wear and tear in the battery through a physical examination. The best way of doing so is to remove the battery from the car altogether. The first thing you need to check is whether or not the battery surface has any bulges. If there are bulges, you have been overcharging your battery. On the other hand, you must also replace the battery if there are cracks on the insulation of the battery terminals.
Another thing you need to look out for is corrosion. You may have a power problem if your battery is corroded. It limits or decreases the ability of the terminals to transfer power. As a result, the battery has to work harder to run all the electronic components, considerably shortening its life. You can clear the corrosion by cleaning the battery. However, it is better to replace it if it has been corroding for years.
Always clean the battery before putting it back in the car. You can easily clean the battery using a soft brush, water, and some baking soda. The brush will enable you to clean the side and top of the battery. Use a dry cloth to remove the excessive liquid. The cleaning process will be the same for the connectors.
An empty or dead battery can have serious consequences especially if you are traveling on a deserted road. However, you know how to test car battery at home now, and therefore, you must check it regularly. It will help you prevent a lot of unnecessary problems and troubles.