How to Start a Car with a Flat Battery: A Step-by-Step Guide

Oh No, Javascript is Disabled!

It looks like you have disabled Javascript in your web browser. In order to take advantage of the full functionality of this website Javascript must be enabled. Please change you browser settings.

Rated Excellent

Free Nationwide Delivery

Full Manufacturers Warranty

Road Tax Included

Competitive Lease Prices

Search our lease deals

Home

News

How to start a car with a flat battery

Having a flat battery can be frustrating and stressful, but with this guide from Car Leasing, you'll have all the information you need to safely jump-start your car and get back on the road. Whether you're a seasoned car owner or a first-time driver, this step-by-step guide is easy to follow and covers everything you need to know about jump-starting a car. Read on to learn how to jump-start your car with confidence and peace of mind.

What is a Flat Battery

A flat car battery, also known as a dead battery, is a condition where a car's battery no longer holds enough charge to start the engine. The battery is an essential component of a car's electrical system and provides the energy needed to start the engine and power other electrical systems. Over time, car batteries can lose their ability to hold a charge due to age, frequent use, and exposure to extreme temperatures. If your car battery is flat, you will not be able to start your car.

A flat battery is often indicated by a weak or non-existent engine crank when you turn the key, warning lights appearing on the dashboard or an illuminated check engine light. In such cases, you will need to jump-start the car or replace the battery to get it running again.

Safety Precautions when Jumpstarting

When jump starting a car, always prioritise safety to avoid damage or injury. First, ensure both vehicles are turned off before attaching the jump leads. Connect the leads in the correct order—starting with the red lead to the positive terminal of the working battery, then to the positive terminal of the dead battery, followed by the black lead to the negative terminal of the working battery, and lastly, attach the black lead to a grounded metal part on the engine block of the car with the dead battery. Avoid connecting the black lead directly to the dead battery's negative terminal, as this can cause sparks and lead to battery explosions. Always wear protective gloves and eyewear (if possible) and ensure the cables do not touch each other or any moving parts.

How to Jump Start a car

If your car's battery is dead and you're unable to start your car, jump-starting is a convenient solution to get your car running again. Jump starting a car requires a set of jump leads or jumper cables, which are used to transfer energy from a working battery to a flat battery. It's important to follow the correct steps to jump-start a car, as connecting the jump leads in reverse order can cause damage to the electrical system.

Before you start the jump-starting process, make sure you have the necessary equipment and follow these steps:

Connect the red lead to the positive terminal on the working battery.
Connect the other end of the red lead to the positive terminal on the flat battery.
Connect the black lead to the negative terminal on the working battery.
Connect the other end of the black lead to a metal part on the engine of the car with the dead battery (not the battery itself).

Once the jump leads are connected, start the car with the working battery and let it run for a few minutes. Then try to start the car with the dead battery. If it starts, it's important to drive it around for at least 15 minutes to recharge the battery. If it still won't start, you may need to use a battery charger or replace the battery.

If you find that you are having to jump start your car frequently it is best to get the battery checked at a garage and follow their instructions on the next steps to take whether that be a new battery installed or fixing an issue with something that is draining the battery.

Can You Jump Start a Car in the Rain?

Yes, you can jump-start a car in the rain, but it is important to take extra precautions to ensure safety. Water is a good conductor of electricity, so it's crucial to avoid getting the jump leads or the battery terminals wet. To reduce the risk of short-circuiting or electric shock, make sure both cars are parked on a dry surface and the engine compartments are as shielded from the rain as much as possible. Additionally, always check that your hands are dry before handling the cables. As long as you carefully follow the proper procedure, jump-starting a car in rainy conditions should be safe.

When Jump starting doesn’t work

If you're unable to jump-start your car, it's best to have a professional handle the battery replacement or use a battery charger to recharge the battery. Certain roadside assistance will help with flat batteries, and you can purchase new batteries from most places that sell car parts.

How to bump start your car

If you don’t have a second car to jump start your car, you may have to bump start your broken-down car. This method works best with two people, or if your car is on a downslope.

NOTE: Never bump start an automatic car. Only use this method if your car is manual.

Leave the ignition on, put the car in second gear and hold the clutch down
Take off the handbrake, and let the car gain some speed
This will happen naturally on a downslope. If this is not the case, have someone push the back of your car.
When the car reaches approximately 10mph, release the clutch
The car should burst into life and will “bump”, hence the name.
If the car successfully starts, leave the engine running for approximately 20 minutes. This will allow the battery to get back up to full charge.

NOTE: Refrain from frequently bump starting your car. This method impacts the catalytic converter that may be fitted. We would recommend buying a new battery if this becomes a common occurrence.

When Jump or Bump Starting Doesn’t Work

If you're unable to jump-start or bump your car, it's best to have a professional handle the battery replacement or use a battery charger to recharge the battery. Certain roadside assistance will help with flat batteries, and you can purchase new batteries from most places that sell car parts.

Flat Batteries on EVs

One of the main concerns when people are considering an EV is the length of time the battery will run for before needing charge. Letting an EV battery run completely flat can damage the electrical components of an EV and is commonly referred to as deep discharge, which can potentially reducing the battery's charging capacity or ability to deliver power.

Most electric vehicles (EVs) will provide ample warning to recharge the battery before it runs out, typically alerting you when the battery level drops to around 15-20% of capacity, much like a traditional fuel gauge in a combustion engine car. The car's sat-nav system, typically included in most EVs, can guide you to the nearest charging point to recharge the battery.

However, ignoring these warnings and continuing to drive the car will eventually lead to the range display going blank, signaling the inevitable. Some EVs may enter a 'limp-home' mode, reducing power to the minimum required to move the car off the road safely. It's worth noting that while the drive battery will be depleted, the car's ancillary systems, like hazard lights, will still operate since they run off the separate 12-volt battery.

Once the drive battery is flat, the vehicle will come to a stop, and recovery will be necessary. In neutral, the car can be moved, but the weight of the battery means it may require some effort to get it rolling. Most new EVs come with free breakdown cover that includes recovery to the nearest charging point or your home if the drive battery is flat. When being towed, the car's wheels may be secured with dolly wheels under each corner to prevent them from turning.

Once you've reached a charging point, you'll need to wait for the battery to recharge fully, which can take a significant amount of time. This underscores the importance of keeping the battery charged to its full capacity, charging little and often to avoid running out of power.

Get your car back up and running

Starting a car with a flat battery can be a challenging and frustrating experience. However, with the right tools and knowledge, it's possible to jump or bump-start your car and get back on the road quickly. Whether using another car or a portable jump starter, it's essential to follow the correct procedures to avoid damage to the vehicle or personal injury. Additionally, taking preventive measures such as keeping the battery charged and in good condition can help avoid flat battery situations. With a little preparation and a clear understanding of the steps involved, jump-starting a car with a flat battery can be a simple task.