A car battery converts the stored chemical energy into electrical energy during discharge while during charging it converts the electrical energy into chemical energy for storage purposes.
Due to several reasons, a battery might fail to hold charge or the chemical reactions intended to happen might fail to happen as expected.
In this article, we want to explore some of the possibilities that can prevent a battery from holding charge as it should.
Sulfation
The process through which lead sulfate forms crystals that are not breakable during charging is called sulfation.
These crystals are really hard to break with the regular charge and once they form and fail to dissociate during charging, they fall to the bottom of the battery and form a sludge leading to battery stratification.
If a battery is stored in a discharged state for long, it becomes prone to sulfation. As the battery also ages, the chemical reactions taking place will produce complex compounds that are hard to break therefore reducing its capacity.
In some cases, you can reverse sulfation by the use of a higher current for charging over longer periods.
Faulty Alternator
We have so far discussed the role of an alternator. It is designed to recharge the battery and keep it fully charged. This alternator is made up of a copper coil and this copper coil spins through a magnetic field.
The coils produce an induced current that alternates as the magnetic poles also alternate resulting in an alternating current. This alternating current is then passed through a rectifier so that it is converted into direct current and then sent to the battery for charging to take place.
When the alternator is faulty, it means that it will not be able to send the needed amount of current to the battery so that it is fully charged. In that case, the battery will remain partially charged and will not hold the required amount of charge.
Faulty Wiring
For the electrical power to reach the electrical equipment that needs it. The power has to pass through a set of wires. When there is a problem with the wires it means the process of transferring the electrical power may not be complete.
This can cause the battery to either lose a lot of power or have little power reaching where it is required.
Back to the alternator. When the alternator wiring is not okay it means even if the alternator is producing the right amount of current charge, the battery may not receive all the charge current.
The connections at the terminals need to be secure and tight. You need to know that any loose battery connections can cause the battery not to store charge as required.
Parasitic Drain
When all power has been switched off at the ignition and power is still being drawn from the battery it is referred to as parasitic drain.
This in most cases happens when there is a problem with wiring. When the car is in frequent movement it might not be so easy to realize a parasitic drain because the power lost might be negligible.
After all, the power lost is quickly replaced by the alternator. The situation is however different in cases where the car is kept idle for long without the engine starting. In this case, you might get shocked when the engine can’t start due to low power.
Battery Corrosion
Corrosion at the battery terminals occurs because the terminals are made of copper which in the presence of sulfuric acid and hydrogen reacts with air. To identify corrosion, you will see the presence of a powdery substance which can be white, bluish, or greenish deposited at the battery terminals.
In most cases, corrosion at the positive terminal will happen when the battery has overcharged while corrosion at the negative terminals will happen when the battery has undercharged.
Corrosion prevents the battery from receiving the required amount of charge and also forms a resistance layer usually between the battery and the connections which hinders the battery from giving out sufficient power.
Deep Discharge
A battery has a terminal discharge level. This is the level at which the battery is capable of discharging power without experiencing any damage. When the battery discharges beyond its terminal discharge level it can get damaged and its capability and capacity to store charge can be affected.
Some batteries are designed to have a higher discharge depth. This means that they can withstand high discharge levels without any difficulties. They are referred to as deep cycle batteries and are mainly used in power backups like the UPS.
Deep cycle batteries can be discharged up to 50% of their rated capacity while an ordinary starter battery like the ones used in cars should not be discharged more than 80% of their rated capacity.
Faulty Battery Cells
We had mentioned earlier that the car battery is made up of 6 cells which are connected in series and each of the cells gives a voltage of 2.1 Volts which gives us a total of 12.6 volts when charged to capacity.
When any of the 6 cells is faulty, it means it will not be able to store the right quantity of charge. This will in turn affect the total voltage output of the series meaning there will be a decline in the power stored by the battery.
Low Electrolyte Levels
We have mentioned before that the battery has an electrolyte which provides a medium for the electrochemical reactions to take place. It is through the electrochemical reactions that chemical energy is converted to electrical energy.
The electrolyte is made up of water at 65% and sulfuric acid at 65%. When the electrolyte levels go too low, the battery is deprived of a medium for the electrochemical reactions to take place.
The electrolyte level can be reduced when there is leakage or when water is lost. If water is lost, we are left with a more concentrated electrolyte that will eventually corrode the plates of the cells.
Extreme Temperatures
The chemical reactions inside the battery are affected by extreme temperatures. When temperatures are high, the chemical reactions are more efficient and the reverse is true when the temperatures get low, the chemical reactions also become slow.
The optimum temperature for reactions to take place is between 50C to 400C.
It is due to this reason that you will notice it is easier to start a car during summer than in winter. Although, the battery will begin to suffer damage when the temperatures go extremely high.
The ability to store charge also decreases as the temperatures go extremely high. The battery will freeze out as well during extremely cold weather and will suffer damage.
Faulty Battery
In some cases, the battery might just be faulty right from the manufacturing stage and such batteries might not be able to store charge. There are tests done individually on the batteries for quality assurance. Some faults however in very rare cases, will pass the checking process.
As the battery is being transported it may also suffer damage. Such damages will be hidden and cannot be seen by a naked eye but you will notice there is a problem when they cannot store charge for long.
Conclusion
The average lifespan of a lead-acid battery is 3-5 years. The battery is designed to hold charge throughout this period.
When batteries experience any of the above-mentioned problems, they might lose the ability to store charge, have their lifespan shortened and as time goes by a replacement will be the ultimate solution.
You can always identify the reasons why your battery is not keeping charge by performing troubleshooting.