How to change your car battery
Abby Wingett | 11th July 2022 | 8 minutes to read
Your car battery generally needs replacing every 3-5 years and installing a new car battery is a job you can easily do yourself. If your engine takes a few extra seconds to start, your lights dim when you turn heating or air conditioning on, or you notice corrosion on the terminals, it may be time to replace your car battery.
Let us show you how to replace your car battery with this Repco Know How piece.
How do you know if your vehicle needs a new battery?
Like any battery powered device, it will give some warning signs that the battery is not in a healthy state. These are not always easy signals to pick up on. Using a battery powered torch as an example, you can tell if it is not shining as brightly every time you use it. Like most of us the first time you notice the problem is when it either won’t work or the light is so dull it is not usable.
A vehicle battery is no different. Its main role in life is to start the engine. Once started, an alternator driven off the engine, kicks in and provides all the electric power to your vehicle. This is the only chance you get to gauge how your battery is performing and like the torch, not always easy to spot.
When you turn the ignition key to start, things like:
- Slow engine cranking. It sounds like the engine is not spinning or turning as quickly as normal.
- Slow to start. Takes longer than usual for the engine to fire up. (Due to the slow cranking)
If you suspect the battery and it is a maintenance free one, check the health indicator light. If not green, the battery is in trouble and needs to be checked. The issue here is it is not a simple problem to diagnose without the right test equipment. If the battery light is green, slow cranking could be caused by other issues, like a faulty starter motor or bad wiring connection.
You need to get the battery properly tested to check. The harsh reality is a failing battery is not easy to identify so that is why so many of us get caught out when it does happen.
The joy is help is on the way. Some newer vehicles are now fitted with battery monitoring solutions. These monitor the health of the battery and will alarm if any thresholds are exceeded. CTEK CTX Battery Sense is a product you can fit to any vehicle battery and by using an app on your smartphone, iPhone (OS 7 up) or Android (OS 4.4 up). It allows you to monitor the health of your battery and will send alerts to your phone if there is a problem.
Steps to changing your car battery:
What will you need to replace your car battery?
- New car battery from Repco using our vehicle finder search to find out which battery fits your vehicle.
- Ratchet
- Ring spanner
- Battery post and terminal cleaner
- Battery and cable protector
- Protective gloves
- Projecta interim power supply
Step 1: Ensure your vehicle is turned off
Before you disconnect your old battery, you will need to ensure your vehicle is turned off and in park mode.
All modern vehicles run electronic control modules to manage a host of engine, transmission, and vehicle functions. These functions rely on a continued supply of power and without this may erase critical management software or memory settings. To overcome this, you can purchase an Interim Power Supply from Repco such as the unit from Projecta below. This ensures these memory functions or important software maps are not erased.
Projecta make a product that uses a small 9V battery to power your vehicle electrics while changing over the battery. Simple to install and ideal for vehicles with digital clocks, programmable stereo systems, keyless entry, electric seats, etc.
You need to buy a new 9V battery to run it. Always check the vehicle manufacturers recommendations before changing the battery.
New keyless entry systems (FOB), battery maintenance systems (BMS) and idle stop start (ISS) functions all need some type of ‘resetting’ when changing over a battery. The reason is the vehicle computer monitors the batteries state. If you change the old battery for the new without resetting, it confuses the system as the new battery will have more charge than the old and the monitor needs to be recalibrated.
All these systems use very little power compared to starting the engine, so even though your battery is flat and will not start the car, it can still power and run a lot of these systems in the background. This is why batteries slowly go flat if the vehicle is not driven regularly. When you switch off the ignition there are other electrical circuits that use power. Even the car clock needs power to run.
Once the ‘electronics’ is sorted the removal and installation is easy. The steps from here will work for older model cars where electronics is not such an issue.
Step 2: Locate and disconnect your old battery from your vehicle
Once you have your safety gear, you will need to locate your battery. Usually, the battery is under the bonnet however sometimes they can be located in other places like behind the seat or in the boot. If you are unsure where your battery is located, check your vehicle manual.
Once you have located your battery you will need to disconnect the terminal by using a ring spanner. Remove the Negative (-) terminal connector & cable first then proceed to remove the Positive (+) terminal connector & cable.
Tip:
It is always a good idea to mark the Positive (+) terminal cable with something before starting to disconnect as a lot of vehicles run the same colour cable (usually black) you do not want to confuse them. Take a picture on your phone before starting is good insurance.
Step 3: Remove clamp and battery from vehicle
Usually, a battery will be held down by a battery clamp which ensures the battery does not move around whilst you are driving around. You will need to remove this clamp to be able to get the battery. Once the battery clamp has been removed you will be able to remove the battery from vehicle however batteries are heavy to take car when removing the battery from your vehicle. When removing the battery ensure the battery is always upright and the terminals are facing upwards.
Step 4: Check you have purchased the right battery and inspect terminals
Put your old battery next to the new battery to ensure terminals are in the right spot and the physical size of the battery are the same. Some battery compartments are a tight squeeze, so it pays to check first.
It is also important to inspect the terminal connectors, hold down clamp and battery tray for corrosion or damage. Clean, fix or replace as required.
Using our CRC battery maintenance product this will help remove acid corrosion deposits, electrolytes, dirt, and moisture from battery surfaces. CRC's battery terminal cleaner is used to neutralise battery acid and electrolytes to help eliminate energy loss and reduce voltage leakage by cleaning dirty connections.
Step 5: Installing the new battery
Put your old battery next to the new battery to ensure terminals are in the right spot and the physical size of the battery are the same. Some battery compartments are a tight squeeze, so it pays to check first.
This process is basically reverse of the removal process. Put the new battery in the tray so the terminals are in the same spot as the old one. Make sure when placing the new battery in that you keep it upright at all times ensuring that the terminals are facing upwards. Reattach the Positive (+) terminal connector & cable first then proceed to Reattach the Negative (-) terminal connector & cable. Once the terminals are connected, tighten them using a ring spanner, the terminals don’t need to be super tight they just need to be a firm fit so the terminals don’t fall off the post.
Reinstall the battery hold down clamp and tighten securely to ensure the battery will not move when driving your vehicle.
Once you have connected up the battery you can use our CRC battery terminal protector which provides a dry, lead-free protective coating that keeps moisture, salts, and road grime from corroding metal contacts. Which will maximise performance, provide long lasting protection and extends battery life.
Tip:
Both connectors should be firm so you cannot rotate them on the terminal posts with your hand. Do NOT overtighten them or use a tool to hammer them onto the terminal posts or damage will result. You can use a protectant on the terminal post and connectors during or after the installation process to help stop corrosion.
How do I dispose of my old battery?
Your old used battery can also be safely recycled at any of our nationwide Repco store locations free of charge. We send old batteries off to be recycled. Simply get in contact with your local Repco and get rid of your old batteries today.
For more information on recycling your battery today check out our know how page battery recycling at Repco.
Benefits of recycling:
- Help build a cleaner Australia for future generations
- Prevents harm to humans and wildlife
- Protects the environment
- Conserves natural resources
- Reduces the amount of waste to landfill
