What does an automotive battery do?

The main function of a traditional automotive battery is to supply a burst of power to the starter when you turn the key to start the car. Beyond that primary function a battery must also have enough power to keep your car running for a short period of time (such as long enough to get you home or to the service station) should your alternator fail. It supplies power when the alternator cannot cope with the electrical demand from the car.

Batteries also supply power to the electrical system when the engine is switched off. Demands made on the battery when the engine is switched off are called parasitic loads. They include anti-theft devices (satellite tracking, immobilisers) and computers.

As vehicles become more sophisticated, the battery is called upon to deliver more and more power to items such as cellular phones, on-board computers and other gadgets that continue to draw power even after the key has been turned off. These power demanding functions mean vehicles require more powerful batteries – sometimes even more than one.

Start/stop batteries provide all of the functions of standard batteries but with increased start/stop cycle life. In start/stop applications much more severe cycling demands are placed on the battery which cannot be met using a standard automotive design.

What are the most common causes for battery failure?

  • Positive grid corrosion (can be accelerated by heat and overcharging)
  • Loss of electrolyte due to heat or overcharging
  • Undercharging with voltages less than 13.8V
  • Physical damage due to vibration
  • Sulphation in storage
  • Overcharging when the charging voltage is not well controlled

How does a battery work?

A battery works by storing electrical energy from the alternator as chemical energy. This chemical energy is reconverted on demand from the electrical system.

It develops voltage from the chemical reaction produced when two dissimilar metals such as the positive and negative plates, are immersed in the electrolyte, a solution of sulphuric acid and water. In a typical starter battery the voltage is approximately 2V per cell, for a total of 12V. Electricity flows from the battery as soon as there is a circuit between the positive and negative terminals. This happens when any load that needs electricity such as the radio, immobilizer or alarm is connected to a battery.

Most people don’t realise that a lead acid battery operates in a constant process of charge and discharge. When a battery is connected to a load that needs electricity, such as the starter in your car, current flows from the battery, whereafter the battery begins to be discharged. As a battery discharges, the lead plates become more chemically alike, the acid becomes weaker and the voltage drops. Eventually the battery is so discharged that it can no longer deliver electricity at a useful voltage.

In the reverse process a battery becomes charged when current flows back into it, restoring the chemical difference (potential) between the plates. This happens when the alternator charges the battery.

This process of discharge and charge in the lead acid battery means that energy can be provided and restored over and over again. This is what’s known as the cycling ability of a battery.



How do I charge my battery?

For best results charge the battery as soon as you know it is discharged and consult the battery specialists at your nearest Battery Centre. To charge your battery, follow these steps and important safety tips:

  1. Read the charger manufacturer’s instructions.
  2. Put on protective eyewear, rubber gloves, work clothes and remove all jewellery.
  3. Place the battery in a well ventilated area.
  4. If applicable, remove the vent caps and check the battery’s water level and, if low, add distilled water to the maximum electrolyte level.. Do not overfill.
  5. To determine if the battery needs to be charged, test it with a hydrometer to determine its specific gravity. Specific gravity is a good measure of the state of charge of the battery.
  6. If applicable, reinstall vent caps before charging.
  7. While the charger is unplugged, connect the leads to the proper battery terminals. Positive to positive and negative to negative.
  8. Set the charger to the proper settings for your battery e.g. 6 volts vs 12 volts, low maintenance vs sealed, standard automotive vs deep cycle.
  9. Plug in and turn on the charger.
  10. Don’t wiggle the connections to check contact while the charger is turned on or plugged in.
  11. Choose the lowest amperage setting initially. Once the charger is on and the battery is charging, you may want to choose a higher amp setting to reduce charge time. Never charge using a current of more than 10% of the rated capacity of the battery. The voltage on charge should be limited to 14.8V.

During charging

  • Keep the vent caps on
  • Don’t allow smoking, open flames or sparks near the battery
  • Don’t allow the battery to become hot to the touch.

After charging

Immediately after the battery is fully charged, turn off and unplug the charger. Disconnect the leads from the battery. Continuing to charge a fully charged battery will severely damage the internal plates and shorten battery life.

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 eyes and face from battery
  • Keep as much distance as possible from battery
  • Read warning labels on battery
  • Do not cause any flames or sparks, do not smoke
  • Read your vehicle instruction manual before jump starting vehicle
  • If you should get acid on your skin or in your eyes, flush with water immediately and seek medical attention.


What sort of maintenance should I perform on my battery?

Modern automotive and light truck batteries need little attention. Check the battery once a year for signs of corrosion at the terminals. Clean the terminals with a mixture of baking soda and water. Keep the top of the battery clean of heavy dirt and oil to prevent low grade short circuiting.

Some batteries are equipped with removable vents so that the electrolyte levels in each cell can be checked and filled with water if the level is low. Always use good quality drinking water or distilled water to prevent iron or other chemicals from contaminating the electrolyte. Be careful not to overfill the cells or acid may be expelled during operation or charging.

How do I install a new battery?

  1. When removing old battery, disconnect earth cable first (usually negative).
  2. Use the correct spanners.
  3. Clean the battery tray and hold-downs with a solution of bicarbonate of soda (baking soda)
  4. Clean the cable clamps and check the cables for damage.
  5. Connect the new battery, beginning with the positive cable.

How do I know when to replace my battery?

The best way to know when to replace your battery is to go to your nearest Battery Centre for a free battery check. The following are the most common warning signals that can indicate a problem with your battery or your charging system:

  • Your starter motor is experiencing slow or interrupted turnover
  • Your battery seems to lose power quickly in cold weather
  • Your headlights dim at idling
  • The battery/charging system warning light on your instrument panel stays on for extended periods after the engine is running
  • To determine if the battery is failing, take it to a qualified mechanic as soon as possible or try testing your battery.

What safety precautions do I have to take while handling a battery?

Acid causes burns and corrodes metal. As a result, you should always wear protective clothing when working with battery acid. Always wear safety goggles to protect your eyes. If acid gets into your eyes, flush with a large volume of running water, then seek medical attention.

If battery acid is spilt in inaccessible or dead space in a vehicle, it can be neutralised with a mixture of water and bicarbonate of soda.

When handling a battery it is also important to remember that they can explode if overcharged. When charging or even on standby, batteries contain hydrogen gas and air in an explosive mixture. It can be ignited by naked flames or sparks from matches, cigarrete lighters, spanners touching both terminals or the incorrect use of jumper leads.

Keep all sources of ignition away from batteries and take special care when jump-starting. 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.

Always switch off all vehicle electrical equipment or charging equipment, when in use, before removing the vehicle of charger leads. This will minimise the possibility of sparks. Also ensure there is sufficient ventilation when charging a battery.

How long can I leave my battery unused?

Lack of use if one of the greatest enemies of a battery, especially an automotive battery which is designed to be charged regularly by an alternator. Any unused battery, regardless of its chemistry, will self discharge over time and if allowed to remain discharged, will undergo severe positive grid corrosion and premature battery failure. The rate of discharge will depend on the type of battery and the storage temperature.

Why does my battery start the car sometimes but not at other times?

This is probably not a battery problem. If the problem occurs only after the vehicle sits overnight or for a day or more before starting, 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 problem continues, visit your local Battery Centre.

How do you measure a battery's performance?

There are two parameters that measure battery performance: voltage and capacity. In very simple terms, the voltage is the force propelling each of the electrons coming out of a battery and the capacity is the number of electrons that can be obtained from a battery.

The voltage of a battery cell is determined by the materials used in it. The typical open circuit voltage of commercial lead acid cells is around 2.13V but the cell is said to have a nominal voltage of 2.00V. This means lead acid batteries with nominal voltages of 2V, 4V, 6V, etc. are possible.

The capacity of a cell is essentially the number of electrons that can be obtained from it. Since current is the number of electrons per unit time, cell capacity is the current supplied by a cell over time and is normally measured in ampere hours.

How do batteries play a role in our lives?


Without lead acid batteries virtually everything but muscle powered transportation would stop. Lead-acid batteries either start or power cars, trucks, buses, trains, rapid rail systems, recreational vehicles and electric wheelchairs. Lead-acid batteries power electric forklift trucks used in warehouses factories, mines and ships. They also power escalators and travelators in airports as well as golf carts used on courses all over the world. On the road, lead-acid batteries power electric law enforcement vehicles, buses, shuttles at amusement parks and mail carrier vans.

Power control

Thomas Edison’s first central electric generating station built in New York City in 1882, suffered many mechanical failures from sudden fluctuations of the load on the generating machines. Lead acid batteries came to the rescue then, delivering large amounts of electricity for short periods of time. They are still used for the same purpose today by electric utilities all over the world.


When the electricity goes out, your telephones stay on. This is because every major telephone company in the world uses lead-acid batteries as backup power to keep telephones systems working during storms, earthquakes and power. The same batteries also backup mobile phone and two way radio systems.

Backup systems

During power outages, lead-acid batteries provide quiet, pollution-free emergency power for critical operations in facilities such as air traffic control towers, hospitals, railroad crossings, military installations, submarines and weapons systems. In environmentally sensitive manufacturing operations, lead acid batteries keep the pollution control system operating during blackouts and brownouts until the plant can be shut down.

Standby systems

Lead-acid batteries power cable TV systems, marine buoys and lighthouses. In remote locations they power railroad crossing signals and instruments that measure seismic disturbances for earthquake research and they store electricity generated by solar panels or windmills.

What are the health hazards associated with lead acid?

Lead in the body is measured by the amount of lead in the blood and sometimes in the bone. According to the Centre for Disease Control and Prevention (CDC) the level of concern for children is 10 micrograms of lead per deciliter of whole blood. Parents should look at the child’s environment to see if there are any sources of lead, such as old leaded paint. If a child has a level of 15 micrograms of lead or more per deciliter of blood, parents should look at the child’s home, school and play environments and their own jobs, hobbies or other situations that could expose the child to lead.

The Occupational Safety and Health Administration (OSHA) threshold for adult workers in battery plants is 50 micrograms of lead per deciliter of whole blood. A worker who tests at a 50 will be moved to a different job in the facility until his or her blood lead level falls. The employee will be counselled and monitored to keep the blood level below the OSHA threshold.

Battery manufacturers and recyclers have education programs and health maintenance programs for their employees, backed up by regular blood lead testing efforts. Regular monitoring of blood lead levels allows a physician to track the success of lead reduction programs. Test results are a critical tool in the employees’ health management programs.

How is environmental pollution controlled at the First National battery plant?

  1. Air filters and scrubbers
    To keep microscopic particles of airborne lead emissions to a minimum, manufacturers and recyclers use high efficiency air filters and wet scrubbers to filter plant air before it is released to the atmosphere. The filters are re-inspected and replaced regularly. The filters are also equipped with alarms, and the process is shut down or re-routed should a filter tear or break.
  2. Clean water
    Manufacturers and recyclers capture and treat process water to keep lead out of streams and rivers. The water is tested before it is released to ensure it meets clean water standards.
  3. Clean air
    At recycling plants, air monitors are installed at the perimeter of each property to ensure any lead in the air is below the regulated limit of 1.5 micrograms of lead per cubic meter of air, averaged on a quarterly basis.
  4. Work practices
    Children can be exposed to lead when a parent who works at a lead plant carries dust home on shoes or work clothes, or in the worker’s hair. OSHA regulations require workers in high lead exposure areas of the plant to leave work clothes and shoes at the plant and to shower and wash their hair before going home. They also require workers in high lead areas to wear a respirator that filters lead particles out of the air a worker breathes. Education programs train workers to wash thoroughly before eating or smoking during breaks and to practice other habits to safeguard their health.
  5. Fugitive emissions
    A regular program of exterior vacuuming or washing down paved areas and capturing and treating rainwater runoff to further reduce emissions. Vehicles that transport lead products typically are hosed down before leaving a facility so that any dust on tyres or the vehicle body is not carried to public roads.

Collectively, all of these practices add up to a very responsible effort to keep even small amounts of lead out of the environment, making a measurable difference.

What is the difference between a car battery and a deep cycle 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 start/stop 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 vehicles (RVs), commercial and stationary applications.

What's the best way to charge leisure batteries?

Fully discharged leisure batteries are charged at a current equivalent to 0.1 times the capacity expressed in Ampere hours (Ah) for a maximum of 13 hours. While 12 to 13 hours would normally be sufficient with a constant current charger, 15 hours may be necessary with a taper charger. Taper chargers are preferred where the battery state of charge is not known.

The exact duration of the recharge required will depend on the extent of the discharge the battery has experienced. As an example a 50 Ah type RR1 battery that has been utilised for 3 hours for lighting a 100W lamp would have consumed 25 Ah and therefore must be charged at 5 Ampere for approximately 6 hours using a constant current charger.

What will happen if I don't charge my battery properly?

The two extremes of improper battery charging are under charging and over charging. Under charging results from a failure to allow the charger to charge long enough to restore the battery to full state of charge. Continually operating the battery in a partial state of charge or storing the battery in a discharged state will result in a condition loosely known as sulphation. Sulphation reduces the battery’s performance and may cause premature battery failure.

Overcharging causes accelerated corrosion of the positive plates, excessive water consumption and in some cases, damaging temperatures within a lead acid battery. Leisure/deep cycle batteries should be charged after each discharge and/or after storage of 30 days or more. We recommend that a deep cycle battery not be routinely discharged below a 50% state of charge.

What type and size of charger should I buy?

Type Automatic chargers are the most convenient. Once you connect the charger to the battery, the charger does the rest. Manual chargers are less expensive and equally effective but they require a greater level of supervision.
Size When selecting the proper size charger, consider the battery’s capacity and the amount of time that will pass between charges. In applications where cycling is infrequent, such as seasonal RV or boat usage, a charge with an output current rating equal to 20% of the battery’s rated capacity will suffice. In applications where battery recharge should be accomplished within 12 hours, a three stage automatic charger may be required.

What is a marine battery?

Leisure or deep cycle batteries often feature thick plates with a high-density active material. The thick plates allow for reserve energy to be stored deep within the plate and released during slow discharge such as trolling or electronic instrument use. The high-density active material keeps the active material in the correct form for longerr, resisting the normal degradation found in cycling conditions.

Deep cycle batteries are used to power trolling motors or lights in a camper. The automotive battery in your car is only asked to deliver short bursts of energy, and then the alternator takes over providing the electricity to run the car and recharge the slightly discharged battery. A marine battery/RV deep cycle, on the other hand, is asked to go through many deep discharges. Often the battery is drained to nearly zero before it is recharged (this is never recommended). This is called “deep cycling”.

Deep cycle batteries are specially designed to withstand many deep discharges. A marine starting battery is similar to an automotive battery; however it is specially engineered to stand up to wave pounding and engine vibration.


What actually happens during the charge cycle of the industrial lift truck battery?

Very simply put, the industrial battery charger takes AC power from the utility company, changes it to DC power, controls the DC power going into the battery and reverses the electrochemical process that occurred during the discharge cycle.

There is a strong misconception that an oversized charger will simply recharge the battery properly in a shorter time period. A battery is designed to absorb a charge at a controlled rate. If it is charged at a faster rate, the energy that it cannot absorb is converted into heat. Cell temperatures rise, and the battery is damaged.

If the charger is not large enough to reverse the electrochemical reaction in the battery within the allotted time, some of the plate will not be converted back to active material. . The battery will not perform in accordance with its ampere-hour rating capacity. More serious is the permanent loss of capacity resulting from repeatedly using batteries that are not properly charged.

What is an equalise charge and why is it important?

The “equalising”charge plays an important role in the continued success of your battery maintenance. Since a battery is made up of individual cells connected in series, usually after a a number of cycles , the cells will be at different states of charge.

The “daily” charge is designed to bring the battery back to full-charge although it is normally limited to 8 hours of charging or less. This allows adequate cooling before the battery returns to service providing that no more than 80% of discharge took place in the previous duty cycle.

The equalising charge continues the daily charge at the finish rate for an additional three hours. This is not harmful overcharging.. Equalising helps each cell perform at maximum levels when peak performance is required. Equalising could be done on a weekend to allow plenty of time to cool down.

How do I care for my industrial lead acid battery?

  1. Keep the battery clean and the top of the battery dry. Check for presence of earth faults (tracking). Earth faults are encouraged by acid on the cells and the steel tray and point to poor maintenance. They can cause damage to electronic circuits and injury to personnel.The tolerance for tracking is zero, i.e. earth faults are not permitted.
  2. Keep electrolyte at the correct level. Do not top up when battery is discharged, unless electrolyte is belowplates. Top up with water to just above the plates then charge. Do the final topping up after gassing has commenced, that is, after 2.40 VPC has been reached, or 80% of charge has been returned.If you have to top up before charging, do not add water to within 10mm of the cover. Fitting an automatic watering system will take the guesswork out of topping up. And remember to use only demineralised water for topping up. Purity of the water can be checked simply with a conductivity meter. Tap water contains impurities which accumulate in the electrolyte and shorten battery life. Using water other than demineralised nullifies the warranty.
  3. Do not overfill. This practice causes loss of electrolyte which varies from one cell to another. Eventually imbalances arise in electrolyte S.G.s, after some time the capacity and recharge ability of every cell will be different. These differences will be aggravated by the manner in which the cells are charged. Weak cells will develop and lead to early failure of the battery.SYSTEMATIC OVERFILLING IS A GUARANTEED METHOD FOR SHORTENING THE LIFE OF THE BATTERY
  4. Do not use more than 80% of the battery capacity. During discharge the positive active material swells. This swelling is in proportion to the depth of discharge. Overdischarge therefore causes excessive swelling, as a result of which the tubes will burst and release active material into the electrolyte. If examination of a battery reveals burst tubes you may be certain that the battery has been overdischarged.The remedy is to fit and use a fuel gauge.
  5. Monitor the health of the battery. It makes sense to do this in order to anticipate failure. Monitor the condition of two or three pilot cells, of which two should be in the centre of the battery. Take regular measurements of temperature, specifc gravity and charging voltage at end of charge. Readings of specific gravity at end of discharge will also provide useful information.ENTER ALL READINGS IN LOGBOOK. When the condition of the pilot cells indicates trouble, or better, at regular intervals, take readings of all cells.An accurate record kept in this way is an important aid later on when troubleshooting.
  6. Ensure proper operation of the charger. The charger should operate in accordance with the battery manufacturer’s recommendations. Ensure that this is happening by having the charger checked periodically.
  7. Equalising. This should be done at least once a week. Equalising means charging the battery at 3-3.5% of capacity, using constant current until the specific gravity and voltages have stabilised over a two hour period. If equalising is not done on a regular basis, it must be done when any or all of the following conditions are found:
    • The specifc gravity measurements never rise above 1.240/25°C
    • The difference between the highest and lowest specific gravity is more than 0.025
    • The difference between the highest and lowest cell voltage on charge is more than 0.10V
  8. Replacing cells. When worn out cells are replaced one at a time, the new cells charge at a higher voltage because their charge acceptance is better than that of the older cells. When several old cells have been replaced, the charging of the old cells will be suppressed while the new cells overcharge.
  9. Period inspection. Carry out the following checks regularly:Check condition and tightness of connectors. Poor connections can create unacceptable voltage losses, cause heat generation and create sparks.Ensure vent plugs are in place.
  10. Storage. Batteries in storage need some attention:Keep clean and dry (for the sake of appearance and to minimise self discharge). Give boost charge when voltages fall below 2.06 (B.S.) or 2.08 (DIN). Check electrolyte levels before charging.

What does a motive power battery do?

It powers the motor that drives an electric vehicle such as forklift truck. Powers accessories like headlights on an electric vehicle. Provides power for a specific purpose on an electric vehicle such as the lift on an electric fork lift truck.

Where does the water in an industrial lift truck battery go?

Proper watering of an industrial lift truck battery is the most important factor in establishing a solid battery maintenance program. The addition of water is usually necessary at weekly intervals by manual installation of an automatic system.

Water (H20) is transformed into gas during the charge cycle. Hydrogen bubbles are produced at the negative plates and oxygen bubbles at the positive plates. The Hydrogen and Oxygen bubbles are released into the air, and gassing (which is perfectly normal and indeed a requirement) occurs in the range of 2.35 to 2.38 volts per cell (this value changes as temperature changes).

What safety rules apply when dealing with a motive power battery?

  • Observe the instructions for use.
  • When working on batteries, wear safety glasses and protective clothing.
  • Do not allow naked flames, hot objects or sparks near the battery due to the risk of explosion or fire. Avoid short circuits.
  • Electrolyte is highly corrosive.Flush splashes of acid out of the eyes or off the skin with copious amounts of clean water, see a doctorwithout delay. Clothing contaminated by acid should be washed out in water.
  • Return old batteries for recycling.
  • Keep away from children.

What are solar power cells and what are they used for?

The solar power cell is designed specifically for solar power installations, particularly those in which it is desirable that maintenance be kept to a minimum. These cells are capable of high cycling – in excess of 1 500 cycles to a 50% depth of discharge.

As most solar power installations are designed to cope with four to five days without sunshine, the cell design provides for a longer discharge period and a lower discharge rate than that of cells in conventional applications.
This cell is also suitable for other renewable energy installations such as wind or water drive generators.

Solar power cells can be used for the following applications:

  • Microwave stations
  • Radio repeaters
  • Any remote or hard to reach installation
  • Any renewable energy installation.

What are valve regulated lead acid batteries used for?

This development in battery technology originated in the late 1960’s. Here the gases that are produced during operation are recombined which minimises water loss. These batteries have been used extensively in Telecoms and UPS applications.

What are tubular cells and for what are they used?

The tubular plate is only used as a positive electrode. Its principal use is for motive power applications, but it is also used for standby applications. It has a very good cycle life which means it can be discharged up to 1 500 times or even more depending on depth of discharge and other operating conditions. In standby applications it offers a small footprint and has a float life of 10 to 12 years.

Tubular cells are used for:

  • Emergency lighting
  • Telecommunications
  • Railway signalling
  • DC emergency systems.

What are Planté cells and for what are they used?

The Planté plate is only used as a positive electrode and is principally used for standby applications, including power stations, telephone exchanges, switchgear operation, telecommunications and emergency lighting.

It benefits from being extremely reliable with 25 years or more life. The Planté uses pure lead cast plates and has moderate to good energy density. Positive plates are 8mm thick pure lead grids for longer life.

Negative plates are of industrial pasted grid construction, for balanced performance and life. . It has the unique ability to provide a minimum of 100% capacity for its entire life. Normally, the end of life is determined when less than 80% capacity is available.

What does a standby battery do?

  • Supplies electrical power to critical systems in the event of a power outage
  • Acts as a voltage stabiliser to smooth out fluctuations in the electrical generation systems
  • Temporarily holds large electrical loads as electric utilities switch from one generation system to another.
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First National Battery manufactures a wide range of battery products across diverse industries.
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