How to Inspect a Car Battery

The battery is the power source of the whole vehicle. It is not meant to be discharged while the engine is off, since the alternator will not be operating to keep it recharged. In order to inspect a car battery, you’ll visually inspect the terminal and cables and check the battery fluid.

If the battery is clear then you can look at the level of the fluid. Most modern vehicles do not have clear batteries. If the battery is not clear, then there may be one or two caps that you can remove to see the fluid in each cell. Any corrosion or signs of leaks around the battery are indications of a problem. Corrosion can be a green or white powdery substance. Don’t ever allow corrosion to come in contact with the skin or eyes because this is an acid and it will burn. If corrosion is present at all, the battery may need to be replaced or there could be a problem with the charging system. Excessive discharging of the battery without the engine running (i.e. listening to the radio, keeping the cab lights on or using any accessory with the engine off) can cause the battery to overheat, which leads to early battery failure and leakage of battery acid. If the battery fluid is low, only use distilled water to refill it. Never add acid to a battery.

How to clean corrosion off a battery temporarily:

The presence of corrosion indicates a problem that should be addressed. However, as a temporary fix, you can clean off the corrosion to get the car started. Start by rinsing off the corrosion with the garden hose. Then disconnect the terminals starting with the negative terminal first, then the positive terminal. Use a mixture of baking soda and water or battery terminal cleaner to rinse off the terminals and battery posts. You’ll see the baking soda reacting with the corrosion to form fizz and bubbles. Use a wire brush or scraper (depending on the type of terminal) to clean the inside of the terminal and battery posts. Then rinse again with more water. Once the terminals and battery posts are clean, reattach the terminals starting with the positive terminal first, then the negative terminal. It is not sufficient just to clean off the corrosion. Again, the presence of corrosion indicates a problem that should be addressed.

How to Inspect a Car Battery is an original article from Crawford’s Auto Repair. Copyright © 2014, Jeff Crawford. Permission is granted to republish this article (text only) for personal or commercial use as long as the content, citation, and copyright notice all remain intact and unchanged. There must be an active “follow” link to CrawfordsAutoService.com. Any image seen with this article is the property of it’s respective author and requires it’s own permission.

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