How to Test and Replace a Bad Car Battery (COMPLETE Ultimate Guide)

The video begins with Chris Fix introducing the topic of diagnosing and replacing a car battery. He emphasizes the importance of first determining the cause of battery failure, whether it's due to the battery itself or other issues in the car. Chris proceeds to explain the process of testing the alternator and checking for parasitic draw, as well as cleaning terminals for a proper electrical connection. He also mentions that he will share tips on choosing the right battery and demonstrates how a battery works by opening an old, bad battery to show the insides. The introduction sets the stage for a comprehensive guide on battery care and replacement.

In this paragraph, Chris Fix focuses on the importance of clean and tight battery terminals for optimal performance. He provides a step-by-step guide on how to clean dirty terminals using warm water and baking soda, and how to sand them to reveal fresh metal. Chris also discusses the use of felt terminal protectors to prevent corrosion and the application of silicone grease to keep terminals in good condition. He then moves on to explain how to check the voltage of a battery using a multimeter, highlighting the significance of a reading around 12.4 to 12.6 volts for a fully charged battery. If the voltage is lower, it could indicate a bad cell, alternator issues, or parasitic draw.

Chris Fix delves into the reasons behind battery failure, using a cut-open old battery to illustrate the point. He explains that each battery cell produces 2.1 volts and a bad cell can lower the overall voltage. He points out that vibration and heat are detrimental to batteries, causing the grids to break and the paste to fall off, which is essential for the chemical reaction that creates electricity. Chris also shares his experience of charging a battery that reads 10.5 volts, only for the voltage to drop once the charger is disconnected, confirming a bad cell. He then guides the viewer through the process of replacing the battery, stressing the importance of getting the correct replacement and understanding the differences between standard flooded batteries and AGM batteries.

This section covers the diagnosis of a bad alternator and parasitic draw as potential causes of battery issues. Chris Fix explains how to test the alternator by checking the voltage output, which should be between 13.6 and 14.6 volts when the car is running. He also describes how to test for parasitic draw by disconnecting the battery and using a multimeter to measure the current in DC amps. Chris provides instructions on how to identify the source of the draw by removing fuses one by one until the amperage drops, indicating the faulty component. He advises that if all fuses are removed and there's still a significant draw, the alternator cable should be checked.

Chris Fix presents an advanced method of replacing a car battery without disconnecting it from the car, thus preserving the car's computer settings and preventing loss of presets and clock settings. He demonstrates the use of high-quality jumper cables to maintain a connection to the car during the replacement process. Chris carefully explains each step, from loosening the old battery to installing the new one and ensuring proper electrical contact. He highlights the importance of not mixing up the jumper cables and the sequence in which they should be connected and disconnected. The paragraph concludes with Chris starting the car to confirm that the battery replacement was successful and that all car settings remain intact.

In the final part of the video, Chris Fix discusses the importance of preventing battery degradation by avoiding vibrations, heat, and keeping the battery charged. He suggests starting the car at least once a week to maintain the battery charge, or using a trickle charger for vehicles that are not frequently used. Chris also addresses the issue of recycling the old battery, explaining that there is a core charge for new batteries that can be redeemed by returning the old one. He encourages viewers to recycle their old batteries, as they are highly recyclable and can provide extra cash, emphasizing that 99% of a battery is recyclable, making it an environmentally friendly choice.