What to do if your car gets a flat battery

Jump to
Car battery

Getting a flat car battery is something nearly every driver encounters at some point, turning a routine day into an unexpected and unwelcome challenge.

The sudden realisation that your car won't start, accompanied by that telltale silence or weak choking sound, can be daunting.

However, navigating such situations becomes significantly easier with helpful tips and tricks 👇

What is a car battery, and how does it work?

The battery is an essential component of every motor vehicle and is pivotal in powering the electrical systems and starting the engine.

Encased in a plastic container, it features two connection points, or terminals, that link the battery to your car's electrical system.

The most common battery is the 12-volt lead-acid battery. It comprises six cells, each producing about 2 volts. These cells are filled with a mixture of sulphuric acid and water, which reacts with lead plates inside the battery. Lead-acid batteries are durable, dependable and more affordable than other battery types, delivering a specific number of engine starts before needing replacing - typically 20,000.

Batteries are required for:

  • Starting the car: The primary role of the car battery is to supply electricity to the starter motor, which then cranks the engine. Once the engine is running, the car's alternator takes over to power the electrical systems
  • Supplying power: The battery provides electrical power to various car components, such as headlights, radio, and air conditioning, when the engine is off or when the alternator can't supply enough power
  • Voltage regulation: It also plays a role in stabilising the voltage to keep the engine running. Without this regulation, the engine might stall or fail to start
Get a quote 👇
Temporary car insurance from 1 hour to 28 days. No deposits, interest or nasty hidden fees. 9 million+ policies sold, 2 million+ cars insured and 2.5 million+ app downloads. Get a quote.

How to avoid getting a flat car battery

Avoiding a flat car battery ensures your vehicle remains reliable and reduces potential inconveniences. You can minimise the risk by:

  • Regularly driving your vehicle: Car batteries recharge when you drive. If left unused for extended periods, batteries can discharge. Aim to drive your car for at least 20 minutes every week to ensure the battery remains charged
  • Limit short journeys: Frequent short trips can prevent the battery from fully charging
  • Check electrical components: Ensure all lights, radio, and other electrical components are turned off when you shut down your vehicle. Accidentally leaving them on can drain the battery.
  • Maintain your battery: Clean the battery terminals occasionally to prevent corrosion, which can hinder the flow of electricity. Baking soda and water with a brush can do the job
  • Test the battery regularly: Use a car battery tester to check your battery's health
  • Replace older batteries: Even well-maintained batteries have a limited lifespan, typically around 4-5 years
Basic maintenance is always a good idea for keeping your car in top condition
Basic maintenance is always a good idea for keeping your car in top condition
Time to go electric? ⚡️
Is it still worth buying a petrol or diesel car as the UK's 2030 ban looms? Learn more.

How to tell that you have a low car battery

When you attempt to start your car and hear clicking or no sound, it often indicates a depleted battery. Dimming headlights, interior lights, or the dashboard warning light illuminating can also suggest a weakening battery.

Additionally, if electronic components like the radio, air conditioning, or power windows start malfunctioning or responding slower than usual, it might be due to a drained battery.

How to charge a battery using a charger

Charging a car battery using a charger is a straightforward process.

  1. Ensure your charger is suitable for your battery type, for example lead-acid, AGM, or gel cell batteries. Different batteries have different charging requirements, and using the wrong charger can damage the battery.
  2. Disconnect your battery from your car by taking off the negative (black) lead, followed by the positive (red) lead
  3. Position the charger at the maximum distance the cables allow from the battery
  4. Connect the charger's clamps to the corresponding battery terminals - positive to positive, followed by negative to negative
  5. Don’t leave the battery unattended for long periods. Check periodically and be aware of excessive heat or any unusual smells
  6. Once the battery is charged, disconnect the clamps
  7. Reconnect the battery to your car - positive first, then negative, and ensure they are securely attached

How to jump-start your car

Jump starting your car kick starts the engine, allowing the alternator to charge the flat battery. If your battery is completely flat, you’re stuck away from home, or you haven’t got a charger, a jump-start is a good solution.

You’ll need:

  • Jump leads - a black negative lead and a red positive lead
  • A second vehicle with a well-charged battery (to prevent damage, avoid hybrid or electric cars)

Here’s a step-by-step guide:

  1. Park the second car close enough so the jumper cables reach, but ensure the vehicles don’t touch
  2. Connect the red jump to the working battery’s positive terminal and the flat battery’s positive terminal
  3. Attach the black jump lead to the negative terminal on the working battery
  4. Attach the other end of the black lead to an earthing point away from the fuel system and battery. Some cars have a specific earthing area, if not, look for an area of unpainted metal
  5. Wait five minutes
  6. Start the engine on the second car and let it run for a minute
  7. With it still running, start the car with the flat battery
  8. If it doesn't start within five minutes, wait a few minutes and try again
  9. Once running, leave both cars idling at a high pace
  10. After ten minutes, turn the engines off and carefully disconnect the cables. Always detach the black lead first, followed by the red lead on your battery, and finally, the red lead from the second car. Ensure that the cables don’t touch each other or the cars
  11. Before the second car drives away, restart your car. Leave it running for around 20 minutes and then take it for a 30-minute drive. Your battery should be fully charged If the vehicle didn’t start after a few tries, the battery might be beyond recovery, or there could be another underlying issue. Always refer to your vehicle's manual; if unsure, consult a mechanic.

How to replace a car battery and what to do with the old one

Removing and replacing a car battery isn’t as daunting as it sounds.

Here’s how to do it:

  1. Ensure the car is turned off and the key removed from the ignition
  2. Disconnect the negative terminal by using a wrench or pliers to loosen the nut on the cable clamp. Be careful not to touch any metal with the cable
  3. Repeat this for the positive terminal
  4. Remove the battery. Some batteries are held in place with a bracket or clamp. If yours is, remove any screws, clamps, or bars holding the battery in place
  5. Use a brush and a mixture of baking soda and water to clean any corrosion from the battery tray and cable connectors
  6. Place the new battery in the battery tray and reattach the bracket or clamp if necessary
  7. Connect the positive terminal first, then the negative terminal. This is the reverse order from when you removed them
  8. Tighten the cable clamps with a wrench, making sure they are secure
  9. Test the process by starting the engine

Car batteries contain harmful chemicals and heavy metals that can contaminate the environment. Therefore, they should always be disposed of responsibly. Most places that sell car batteries or scrap metal collectors offer a recycling or safe disposal service.

Don’t let a flat battery ruin your road trip
Don’t let a flat battery ruin your road trip

Is a flat battery covered by breakdown cover or car insurance?

Whether a flat battery is covered by car breakdown cover or insurance largely depends on your specific policy details and the provider.

Most standard car insurance policies don't cover flat batteries unless the damage is due to an insured event - an accident or incident, such as vandalism, that affects the battery. So, turning to your regular car insurance policy might not be fruitful if your car fails to start or function due to a flat battery.

However, breakdown cover, either as an optional extra on your insurance policy or as separate cover, is specifically designed for when your vehicle encounters mechanical problems or failures, including issues like a flat battery. If you have breakdown cover and face a dead battery, the service usually includes assistance to jump-start your vehicle. If a jump-start doesn’t solve the problem, the cover might also help transport your car to a nearby garage.

Some breakdown cover providers offer specific battery cover, which may cover the cost for replacing a battery if it cannot be recharged or repaired.

The specifics of what's included in your insurance or breakdown cover depends on your provider and the level of cover you have chosen. Make sure you read the small print when considering which policy to purchase.

Cuvva’s temporary car insurance policies are always fully comprehensive, with no nasty deposits, tie-ins or hidden fees. It only takes a few minutes to get a quote.

Updated on 13th October 2023