Just like any other gadget or equipment, batteries have a specified timeline after which they will need replacement. Many factors determine how long a battery will last and whether it will be able to start the car engine
Generally, car batteries last for 3-4 years even though this duration depends on the battery type and other factors. A Nickel-metal hydride battery will last 7-8 years, a Lithium-ion battery can last 6-8 years, an absorbent glass or gel battery can go for 5-6 years depending on its maintenance while a flooded lead-acid battery will go for only 3-4 yrs
The mentioned years are just an approximation from conducted surveys however you need to acknowledge that most batteries will last longer than the mentioned timelines.
Factors That Determine the Lifespan of a Car Battery
Temperatures
For batteries to provide power, the chemical energy stored has to be converted into electrical energy. For this conversion to be done, there are chemical reactions that have to take place.
The rate at which the chemical reactions take place depends on the temperature. In warm environments, the reactions take place faster compared to colder environments. This answers the question of why it is easier to start a car during summer than winter.
How powerful a battery is, is measured by its cold cranking amperage (CCA) which is the quantity of current the battery can be able to provide for at least 30 seconds at OOF. When a battery is charged to capacity, it can be able to tolerate low temperatures up to -300C. A discharged battery will freeze at -20C
When temperatures are extremely cold, batteries tend to freeze. A frozen battery will make the battery electrolyte expand. When the electrolyte expands it makes the plates of the battery swell and detach and also touch each other. This causes the casing of the battery to swell outwards and can even crack.
Such a battery will most likely suffer from a short circuit if you try charging them. When there is a short circuit in a battery, the internal resistance increases and in turn an increase in the inside temperature and hence heat. As the levels of heat increase the battery will suffer from thermal runaway and what follows suit is the battery melting, catching fire, and exploding.
Extremely high temperatures weaken the welding that is used to hold the plates in place. The plates also become soft in extremely high temperatures. When the car is in motion and there are vibrations, these already weakened plates can cause a short circuit.
When dealing with a frozen battery, the short circuit can lead to permanent failure of the battery.
To avoid the battery from suffering from temperature fluctuations, Insulate the battery. Lithium-ion batteries are capable of surviving more extreme temperatures as compared to lead-acid batteries.
Driving Techniques
Driving habits have a huge impact on how long a car battery can last. For instance, if you are used to doing short trips with a sudden engine switch off, then the battery may not last long.
When starting the engine, power is drawn from the battery to the starter motor so that the engine is cranked. For the drawn power to be topped up, the alternator has to be given time.
By now we are all aware that the mechanical energy of the engine is converted into electrical energy by the alternator. The energy that is produced thereafter is in AC and it has to pass through the rectifier for the conversion to DC to happen. It is the DC that is later directed to have the battery charged.
To avoid spoiling the battery, the amount of DC that is sent to the battery has to be regulated. This implies that the alternator charges the battery at a slow rate so that the battery is not damaged.
What happens when you drive for short distances and switch off the engine is that the alternator is not given ample time to top up the battery charge.
As the car engine is started again, more power is drawn from the battery, and the alternator is not given a good time to have the battery recharged. As this continues, at long last the battery power will get too low to the point that it can’t crank the engine
As the charge levels decrease, the battery gets destroyed and sulfation may kick in. It is recommended to have the engine running for about 20-30 minutes after starting so that the alternator gets time to recharge the battery.
The amount of DC sent to the battery is regulated to avoid damaging the battery. This means the alternator slowly charges the battery to minimize damage as much as possible.
Maintenance
For a battery to give the recommended service, it has to be well maintained. You need to check the battery regularly to ensure that it is in good condition. Checking the battery regularly will help in identifying problems early enough and having them sorted before the battery gets damaged.
The electrolyte levels need to be checked from time to time. As the battery charges, the water that forms part of the electrolyte breaks down into hydrogen and oxygen gas through a process called electrolysis.
These gases will later recombine back to the water but a certain percentage of the gases escape and this results to the reduction in water levels. When the electrolyte levels drop below the required level, distilled water is added to the battery.
The battery terminals need to be free from corrosion. When corrosion happens, a layer is formed and this layer prevents the battery from receiving charge from the alternator. When charge levels get too low, the battery can suffer from sulfation or get destroyed.
The battery should always be kept clean and free from dirt and foreign particles. The dirt and foreign particles enhance corrosion.
Charging System
For the battery to be fully charged, the charging system needs to be in good condition. In lead-acid batteries when they are kept fully charged, they last longer than when the charge levels are less than the required charge.
When the charging system is faulty, it means that the battery will not get the required amount of power to have it fully charged.
Always have the battery charging system checked for any loose connections, corroded connections, or cut wires that can hinder current from flowing. In case you identify a damaged wire or cable, have the replacement done immediately.
You need to have a look at the battery charging safety precautions so that you avoid battery hazards such as electric shock which are associated with charging.
Structural Failure
The car battery is made of 6 cells that are connected in series to give a voltage of 12v. Each of the 6 cells gives a voltage of 2v and is made up of several plates that are joined together.
The battery can fail when there are so many connections. A fault in one cell can shorten the lifespan of the battery. To help in identifying faults in the cells, tests like impedance tests and specific gravity tests can be done.
Deep Discharging
The battery will suffer permanent damage if the lead-acid battery is deeply discharged below the recommended terminal discharge level. The recommended discharge level is 80% of the rated capacity.
Some cells in the battery will likely suffer polarity reversal if the battery is deeply discharged. When the polarity is reversed the working of the battery cells is interfered with and such damage may not be reversed even if you connect the battery to the charger.
Time
As the battery gets old, it becomes weak and it gets to a point where it can no longer work or accept charge.
As the battery charges and discharges, there are complex sulfur compounds that will be formed. The compounds are hard to break down and this leads to the negative and positive terminals of the battery suffering from damage.
When a battery gets to this stage, the only remedy is to have a new one. Even changing the battery electrolyte will not help at this stage. The best thing to do at this stage is to dismantle the battery and have its components recycled.
Conclusion
There are things you can do to lengthen the lifespan of your battery. Proper maintenance of the battery can help prolong the life of the battery. How long the car battery stays charged will depend on how well the battery maintenance has been carried out.
Car batteries being a vehicle component, I am certain are not the cheapest component of a vehicle, and therefore proper maintenance is needed to cut on the costs of having to do time-to-time replacements.