man checking car battery

MOT

3 mins

How to test your car battery for loose connections

December 11, 2023

Most car owners know the frustration of trying to start a vehicle only to be met with the disheartening sound of silence or the dreadful clicking noise that suggests a battery problem.

Although it can be easy to jump to the conclusion that you need a new battery, sometimes the issue isn’t a dead battery, but rather loose connections.

In this guide, we will walk you through the process of testing your car’s battery for loose connections to ensure your vehicle runs smoothly.

If you’re unsure what’s causing problems with your car’s battery, get it checked by professional mechanics in Caura.

The importance of checking your car battery for loose connections

A properly functioning car battery is essential for the smooth running of your vehicle. The battery supplies electricity to all your car’s electrical components, and any problems can have a big impact.

Loose battery connections can result in erratic or unreliable performance, or even prevent your car from starting at all. Hence, it’s crucial to regularly check and maintain your car battery’s connections.

What you’ll need

  • Protective gloves
  • Safety goggles
  • A wrench (usually 10mm or 8mm, depending on your vehicle)
  • A solution of baking soda and water
  • A battery load tester (optional)

The process

Step 1: Safety first

Before you begin, ensure that you’re in a well-ventilated area and away from open flames or sparks as batteries can emit flammable gases. Wear your protective gloves and goggles to shield yourself from the corrosive battery acid.

Step 2: Locate the battery

In most vehicles, the battery is found under the hood, though in some it might be in the trunk or under the backseat. Look for a rectangular box with two cables attached to it.

Step 3: Inspect the battery

Visually inspect your car’s battery for any obvious signs of wear and tear, leaks, or corrosion. The presence of a white, chalky substance on the terminals often indicates corrosion, which could be the cause of a loose connection.

Step 4: Check the battery connections

Gentle wiggle each battery cable. If they move freely, they’re not properly secured. Take note that a properly secured battery connection will be firm and won’t move when you try to wiggle it.

Step 5: Clean and tighten the connections

If you detect any looseness or corrosion, it’s time to clean and tighten the connections. Here’s how:

  • Disconnect the battery: always start by removing the negative cable (usually black or marked with a ‘-‘). Then, remove the positive cable (red or ‘+’). Use your wrench to loosen the bolts, but be careful not to let the two terminals touch
  • Clean the connections: once the cables are disconnected, use a solution of baking soda and water to clean both the battery terminals and the cable ends
  • Reconnect the battery: once everything is clean, reconnect the battery and tighten the bolts. Start with the positive cable this time, then connect the negative. Ensure the cables are securely attached by trying to wiggle them again. If they don’t move, you’ve achieved a secure connection

Step 6: Test the battery (optional)

If you have a battery load tester, you can now check the voltage of your battery to ensure that it’s operating at peak performance. A fully charged battery should read around 12.6 Volts If your battery reads less than 12.2 Volts, it may need to be charged or replaced.

How long does a car’s battery last

The lifespan of a car’s battery can vary depending on factors such as the quality of the battery, driving conditions, climate, and maintenance.

On average, a car battery can last anywhere from 3 to 6 years. However, some batteries may last longer, while others may require replacement sooner.

Regular maintenance, such as keeping the battery terminals clean and secure and testing the battery’s health periodically can help prolong its lifespan.

You can book all maintenance work including an MOT test, servicing or repairs via over 7,000 garages in the Caura app. The best part - book in Caura and get access to exclusive pricing!

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How is the battery tested during an MOT test and when will it result in an MOT failure

During an MOT test, a car’s battery is typically checked as part of the overall assessment of the vehicle’s electrical system. The specific battery test procedure may vary slightly depending on the testing facility, but generally, the following aspects are evaluated:

  • Visual inspection: the tester will inspect the battery for any visible signs of damage, leakage, or corrosion. They will also check the battery terminals and connections for tightness and security
  • Battery voltage: using a voltmeter or battery tester, the tester will measure the battery’s voltage to ensure it has an adequate charge. A health battery should typically have a voltage of around 12.6V or higher
  • Battery load test: this test assesses the battery’s ability to deliver power under load. The tester will use a specialised device to apply a simulated load to the battery while monitoring its voltage and performance. If the battery fails to maintain an acceptable voltage level during the test, it may indicate a weak or faulty battery

If the battery fails any of the above tests it will result in an MOT fail. Additionally, if the battery is found to be leaking, damaged or improperly secured, it will result in an MOT failure.

How can Caura help?

If you’re unsure why your car is not starting, or if the battery warning light turns on – don’t worry!

car battery warning light on car

Download Caura for free and get your car battery health checked by professional mechanics to minimise the risk of an MOT failure.

The MOT test primarily focuses on the safety and emissions aspects of a vehicle, so while a faulty battery can result in a failed MOT, it does not necessarily mean that the battery is entirely dead or incapable of powering the vehicle. It is recommended to address any battery issues promptly to ensure reliable vehicle operation.

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