What is a car battery? Basic information about car batteries you need to know

What is a car battery?

Basically, battery Cars are considered a secondary power source, operating in the process of converting mechanical energy into electricity and providing energy for vehicle equipment. The battery will provide current during times when the alternator is not fully charged (engine stopped) or cannot meet the needs of the vehicle's electrical equipment.

Classification of car batteries

• Dry battery

A dry battery is a type of battery with a closed structure that does not require regular water addition. Basically, the inside of the battery is not completely dry but still contains H2S04 acid in gel form.

• Water battery

This is a type of battery that uses liquid inside (H2SO4 solution of appropriate concentration), combined with alternating lead and metal foil. 

Structure, functions, operating principles and technical specifications of car batteries 

Structure of car battery

Car batteries are usually divided into internal and external structures.

As for the inside, the battery consists of small compartments containing positive and negative plates. In the middle is a shield with a bar connecting the two panels together. The cathode and anode consist of different electrolytes.

The external structure of a car battery includes a battery shell and stack, used to connect the power source of this battery to another battery or other power source. For some open-designed bottles, there is also a vent button, which functions to help air escape.

Function of car battery

Car battery components perform the following main functions:

• Stores and provides power for vehicle operations such as starting the vehicle, electric windows, air conditioning system, electric lock, power memory, ECU...
• In addition to car fuses, batteries help protect vehicle components from sudden surges in electrical current when the alternator system fails.

Operating principle of car battery

The operating principle will take place in two processes:

• The charging process occurs because the battery is charged
• The discharge process is due to the battery being connected to an electricity consuming device

Technical specifications on car batteries

• Battery voltage (V)

The internal structure of the battery consists of many compartments, each compartment will produce an average voltage level of 2.1 V/cell. Car battery voltage depends on the number of plates and material of the plates, the electrolyte solution concentration of about 0.25% is standard.

In other words, car battery voltage is the voltage between the positive and negative terminals of the battery. The unit of measurement for battery voltage is Volt (V). And the voltage of a car battery is usually 12V. This is the first car battery parameter to consider when choosing to buy.

• Tank capacity (Ah)

Battery capacity is the amount of electricity discharged in a certain time at a certain current. For example: An 80Ah battery discharges 4A of electricity, the time it takes for the battery to run out of power is 20 hours. But discharging with an amount of electricity of 10A, the time the battery runs out of electricity is 8 hours.

The higher the capacity of the battery, the greater the discharge capacity, depending on the discharge current. Therefore, when replacing a new battery, you need to choose a battery with a larger capacity (no more than 10Ah) or equal to the capacity of the old battery. However, if the battery capacity is large, or the battery is not fully charged, over time the battery will be corroded and gradually damaged.

The unit of measurement for tank capacity is Ampere-hour (Ah).

• Cold start current (CCA)

Cold starting current abbreviated as CCA (Cold Crank Amps) is a parameter that measures the energy provided for the engine's starting process. More specifically, CCA is when the battery supplies current for 30 seconds at approximately -17 degrees Celsius (0 degrees Fahrenheit) until the voltage drops below the allowable limit.

In cold regions, where temperatures are often below zero (degrees Celsius), it is often difficult to start a car because the transmission and engine oil freeze and the engine parts do not function properly. At this time, CCA is very important, you must choose a battery with CCA parameters higher than the recommended value to make the engine operate easier and avoid damage.

On the contrary, in tropical, hot climates, transmission oil and engine oil do not condense, so there is no need to choose a battery with a too high CCA index.

• Hot start current (HCA)

Hot starting current, abbreviated as HCA (Hot Cranking Amps), is similarly determined as above but the temperature is about 27 degrees Celsius (80 degrees Fahrenheit), is the current provided by the battery until the voltage is below the prescribed level.