1. When do car batteries fail?
Currently there is no precise way to predict exactly when a battery will fail. However, periodic battery checks can help give warning of impending failure. Call your local Battery Centre for a free check.
It’s always a good idea to check your battery before holidays or a long trip. If you know the battery is old, you may want to consider replacing it as a precaution.
Cold weather is known to slow down the chemical reactions that generate electricity in batteries. As a result, older batteries will have more trouble starting vehicles in cold weather. The increased use of headlights, heaters, demisters, windscreen wipers and so on can also increase the load on a battery, lowering the amount of charge available from the alternator to the battery.
Hot weather can trigger problems in old batteries, especially if the air conditioner is suddenly being used continuously and many short trips are made throughout the day. Modern vehicles with small grille areas often have high under-bonnet temperatures, which can also lead to battery problems. Higher operating temperatures can lead to reduced battery life.
2. What are key hazards when handling a battery?
When being charged, or even when not in use, batteries may contain hydrogen gas and air in an explosive mixture. This gas can be ignited by naked flames from matches, cigarette lighters, sparks from short circuits caused by spanners or incorrectly connected jumper leads. Always disconnect the earth lead first and replace it last when removing or replacing batteries. This will minimise the risk of a short circuit between tools and vehicle frame.
Battery electrolyte contains sulphuric acid that can cause damage to eyes, skin or clothes if spilt or splashed. Flush the eyes with running water and seek medical help urgently. Wash or hose off splashes with water. Baking soda and water may be used to neutralise electrolyte and in inaccessible spaces on a vehicle.
3. How can I avoid battery problems?
- Ensure that the vehicle charging system is in order.
- Ensure battery terminals are free of corrosion and are tightly fitted.
- Ensure the battery is held in place in the vehicle and that it is not loose.
- Ensure your battery is the right capacity for your vehicle.
- Make sure there are no short circuits or continuous drains of current (such as an alarm or immobiliser) over long periods without the battery being charged.
- Avoid using jumper cables, as this is likely to damage the battery terminals.
- Periodically ensure the battery is fully charged by measuring the specific gravity of the electrolyte.
- Perform regular battery checks at your local Battery Centre.
4. How do I jump-start a car with jumper cables?
Always try to avoid using jumper cables unless absolutely necessary. If you have no other option, follow these steps, but always check your specific vehicle instructions before attempting to jump-start (refer to the manufacturer’s handbook):
- Set the handbrakes of both cars and place in ‘neutral’ or ‘park’. Turn off all switches. Ensure vehicles are not touching each other.
- Connect the red cable clamp to the positive post of the dead battery. (A)
- Connect the other end of the red cable clamp to the positive post of the live battery. (B)
- Connect the Black cable clamp to the negative post of the live battery (C)
- Make final connection on engine block of stalled car – as far away as possible from battery. (D)
- Attempt to start ‘dead vehicle’ with ‘live vehicle’ engine OFF. If vehicle has not started in 15 seconds, stop procedure and check ignition and fuel systems.
- To remove cables, reverse this exact procedure.
5. How do I know when to replace my battery?
You might need to consider replacing your battery if:
- Your starter motor is experiencing slow or interrupted turnover.
- Your instrument panel battery light indicates battery discharge for extended periods after the engine is running.
- Your battery seems to lose power quickly in cold or extended starts.
- Your headlights dim at idle.
Any of these warning signals may also indicate a problem with the electrical system in your vehicle and not necessarily a battery failure. A battery that is about to fail will often give little or no warning. If you suspect that your battery is failing, have it tested or replaced as soon as possible at your local Battery Centre.
6. Can a battery really explode?
Yes, so when working with or near a battery, or jump starting a vehicle, always:
- Wear glasses or safety goggles
- Shield your eyes and face from the battery
- Keep as much distance as possible from the battery
- Read warning labels on your battery
- Do not cause any flames or sparks near a battery
- Read your vehicle instruction manual before jump starting
If you get acid on your skin or in your eyes, flush with water immediately and seek medical attention.
7. How long can I leave my battery unused?
Lack of use is one of the biggest causes of battery failure – especially in automotive batteries that are designed to be charged regularly by an alternator.
Any unused battery, regardless of the type, will self-discharge over time and if allowed to remain discharged, could suffer battery failure. The rate of self-discharge depends on the type of battery and the storage temperature.
8. Why does my battery start my car sometimes but not other times?
This is probably not a battery problem. If the problem occurs only after the vehicle is not used overnight or for a day or more before starting, then the problem is often a low state of charge.
If the battery starts the vehicle once the vehicle has been started recently, test your battery to determine its state of charge. Also make sure that the alternator is adequately charging and that all the connections are good. If the problem continues, see your local Battery Centre.
9. What is the difference between a car battery and a leisure battery?
A car’s battery is designed to provide a very large amount of current for a short period of time – known as micro-cycling (except for stop/start vehicles). This surge of current is needed to turn the engine over during starting. Once the engine starts, the alternator provides all the power that the car needs. Used in this way a car battery can last a number of years. To provide a large amount of starting, a car battery uses thin plates in order to increase the plate surface area.
A leisure battery is designed to provide a steady amount of current over a long period of time. It can provide a surge when needed but less than a car battery can. Leisure batteries are also designed to be discharged over and over again (something that would ruin a car battery very quickly). To accomplish this leisure batteries sometimes use thicker plates and glass mat separators are added to increase the life of the positive plates.
The purpose of a leisure battery is to provide power for trolling motors, uninterrupted power supplies (UPS) and other accessories for marine, recreational vehicle (RV), commercial and stationary applications.
10. What is overcharging?
Overcharging is charging beyond the time necessary to fully charge the battery or charging a battery at an excessive rate in amps. It results in corrosion of the positive grids and damage to the positive active material in the battery therefore reducing the battery’s ability to carry the starting current.
Overcharging is usually accompanied by heavy gassing (beware of the risk of explosion) that will accelerate the shedding of the active material from the positive plates.
Overcharging is also usually accompanied by high electrolyte temperatures resulting in rapid deterioration of the plates and separators. Overcharging may cause buckling of the plates leading to perforation of the separators and internal short circuits.