Checking Car Battery Health At Home: What Causes Draining?

Your car's battery is vital to keeping your engine, air conditioning, electrical system, and even your music running. A dead or mostly drained battery can lead to your car failing to start, struggling to activate all its features (including safety ones), or leaving you stranded.

Even if it's not fully dead, a car battery that's routinely drained can experience a shorter lifespan, forcing you to replace it earlier. Malfunctions can harm your ability to drive and necessitate jump-starts at the worst times.

So what drains a battery? Is checking car battery health possible by yourself? And how can you improve its lifespan? Here's everything you need to know about safeguarding your car battery:

Common Battery Drains That Impact Its Health

Flat batteries are the leading cause of vehicle breakdowns. That's partly because so many factors impact battery health, making it a widespread issue for new cars and old, well-maintained ones and neglected alike.

Luckily, most causes of a dead or drained battery are avoidable.

• Lack of use – Car batteries are designed to hold their charge, but this is limited when the car is not routinely used and the battery has no opportunity to recharge itself. Abandoned or rarely used cars are likely to develop flat batteries.

• Leaving something electrical on – Leaving your headlights or internal cabin light on can drain your battery. This also applies to music left playing while the engine is off; the battery is being used to power this, but it's unable to recharge itself while it does.

• Cold weather – Batteries of every kind do not like the cold. After long nights with the engine off, your battery will have less charge and may struggle to start on chilly mornings. The older your battery is, the more susceptible it is to the cold.

• Short journeys – If your car never gets a good run, the battery will never receive a full charge, reducing its ability to hold charge and, thus, shortening its lifespan.

• Dirty battery terminals – If the casing and surrounding systems for your battery are poorly maintained (with dirty, grim, or even mould growing on them), this can prevent your battery from transferring power to the vehicle.

• A faulty component, such as the alternator – This crucial part recharges your battery when the engine is running. If it's faulty, the battery will use its energy reserve until it's gone.

• Age - Car batteries have a lifespan of about 5-7 years. Older batteries can't recharge as effectively as newer ones, and may eventually stop taking a charge altogether.

How To Check Your Battery Health At Home

If you're curious or concerned about your battery's health, you can take it to a shop like Autofusion for an inspection. A mechanic can assess the state of your battery, give estimates on its remaining lifespan, or swap it out for a fresh one if needed.

However, a professional isn't strictly needed for checking the overall health of your battery. If you want an update to better understand the condition of your battery, here are 4 ways you can do this at home:

1. Check The Voltage

If you regularly check your car's battery, it's worth buying a voltmeter. This tool can be found at most auto centres or hardware stores for less than £20. It will safely test your car battery's voltage and provide you with a readout. To use it:

• Turn off your car and any accessories that could drain the battery - including the ignition, air conditioning, headlights, or radio.
• Carefully remove the covers on the battery terminals.
• Connect the positive side of the voltmeter to the positive (red) terminal first.
• Next, connect the negative side of the voltmeter to the negative (black) terminal.
• Check your reading.

A healthy battery should read between 12.4V and 12.7V. A reading of just under - like 12.3V - can indicate your battery is only 75% charged.

2. Try The Headlight Test

Checking your vehicle's headlights can give you an indication of your battery health. To perform this test:

• Turn on your car's headlights
• Check whether they look darker than normal.
  • If that's the case, your battery may be low.
• Put your foot on the accelerator slightly.
  • If the headlights get brighter, this can indicate a faulty alternator, which isn't supplying enough current to your battery.
• Your headlights should stay at a stable brightness when revving.

3. Battery Health Indicator

In modern cars, most batteries have a in-built battery health indicator. The indicator will have an arrow that turns either red or green, depending on the state of the battery.

• Red indicates low voltage
• Green indicates good condition
• When the battery is completely flat, nothing will show

4. Physical Check

Conducting a visual check can provide a surprising amount of insight into your battery's health, if you know what to look for.

• Turn your car and any accessories off
• While it's still in the engine bay, check for any corrosion on the battery using a good torch.
  • Battery acid is corrosive. Should you notice a sulphuric smell, or bubbling or dried liquid, take your car to a shop like Autofusion.
• If there are no cracks or liquid to be seen, remove your battery from the engine bay for a thorough inspection.
  • Ensure you carefully remove the negative (black) terminal first, and the positive (red) terminal last to keep yourself safe.
  • See full instructions here on how to remove the battery.
• Check for any bulges, which can sometimes suggest overcharging.
• If there are any cracks, you must get your battery replaced as soon as possible.

How To Keep Your Car Battery From Dying

Prevention is better than repairs, and certainly less expensive than replacements. Fortunately, there are many ways to keep your battery from dying in the first place:

• Keep your battery terminals clean and free of debris
• Ensure that the connectors are tight and have not come loose
• Regularly carry out inspections and tests to resolve small issues before they become big problems
• Start your engine up regularly and leave your car running for a little while
• Avoid driving at night or early in the morning, when the weather is coldest
• Purchase a battery cover to protect it from the cold
• Clean away any corrosion from the terminals using a toothbrush and a solution of baking soda and water
• Buy a trickle charger to keep your car battery topped up

Aside from all that, be sure to check the age of your battery. All car batteries are stamped with a code indicating the date that they were manufactured. The majority of car batteries are designed to last for 5-7 years; any longer than this and the battery is likely to fail, especially in the cold.

Get A Free Battery Health Check

If you're unsure about the condition of your car battery, then come in for an Autofusion free battery check. Available at centres around the U.K., we'll assess your vehicle for corrosion on the terminals, as well as the voltage output and the charging rate of the battery. This gives you a clear view on what condition your car battery is in.