Lead-acid batteries are widely used in automobiles, inverters, backup power supply photovoltaic systems, etc. Unlike tubular and maintenance-free batteries, lead-acid batteries require proper care and maintenance to extend their lifespan. Lead-acid batteries consist of a series of plates immersed in a sulfuric acid solution. These plates have a grid on which the active material is attached. The plates are divided into positive plates and negative plates. The positive plate contains pure lead as the active material, while lead oxide is attached to the negative plate.
To make the connection, connect all the positive plates in series with one end exposed as the positive terminal. Likewise, all the negative plates are connected together and connected to the negative terminal. Starting or cranking also known as SLI (Light Starting Ignition) batteries provide high current to start the engine in cars and generators. They have more plates than other lead-acid batteries. Deep cycle batteries are designed for many charge/discharge cycles and have thicker plates.
A fully charged battery can discharge its current when connected to a load. During the discharge process, sulfuric acid combines with the active materials on the positive and negative plates, resulting in the formation of lead sulfate. During this process, hydrogen atoms from sulfuric acid react with oxygen to form water. This causes electrons to be released from the positive plate, which will be accepted by the negative plate. This causes an electrical potential to build up across the battery. The electrolyte in a lead-acid battery is a mixture of sulfuric acid and water with a specific specific gravity. Specific gravity is the weight of an acid-water mixture compared to an equal amount of water. The specific gravity of pure free ionized water is 1.
Inside the battery, there are arrays of battery cells called cells. In a 12-volt battery, there are six cells, each rated at 2 volts. The current carrying capacity of a lead-acid battery is usually expressed in Ah (Ampere Hours). One Ah is equal to 3600 coulombs of charge. Ah is the battery’s ability to deliver 1 amp of current in 1 hour. Therefore, a 100 Ah battery can provide 1 amp for 100 hours. Battery ratings are based on the rate of discharge through a load over a specific period of time. For example, a 100Ah battery discharges at a rate of 5 amps for 20 hours. A battery cycle is defined as a complete discharge and charge cycle. This cycle typically involves discharging from its 100% charge to 20% charge, and then from 20% to 100% charge. Batteries can be kept healthy if they are discharged and charged regularly. Deep discharging to 50% and then recharging to 100% daily will increase battery life. Therefore, it is best to discharge and charge the inverter and emergency batteries every day or at least every two days. Starting and charging your car battery every day will extend its life.
Adding water is another important aspect of battery maintenance. When batteries are discharged and charged, violent chemical reactions occur and heat is generated. This evaporates the water inside the battery and the specific gravity of the electrolyte changes. Therefore, if the water level drops below the required level, the battery must be topped up with ion-free distilled water. Do not add too much water as it may short out the battery plates. If the battery is not used, 4% self-discharge occurs every week. For example, a 125 Ah inverter battery will self-discharge at 5 amps per week if it is not allowed to discharge through the load.
In order to keep the battery in good condition, battery balancing is necessary. Due to age, all batteries charge unevenly, some batteries charge quickly and others charge slowly. Equalization can be done by overcharging the cells slightly so that the weaker cells are also fully charged. A fully charged 12-volt car battery has a terminal voltage of 13.8 volts, while a 12-volt tubular battery has a battery voltage of 14.8 volts.
Sulfation is another factor that affects battery efficiency. During the discharge process, lead sulfate will be formed, which will accumulate on the plates. This prevents charge release and acceptance. But these lead sulfate crystals will be removed when filling with water and charging, so it is best to load immediately after filling with water. If lead sulfate accumulates too much, it must be desulfurized using a desulphurization unit (which provides pulses of electrical current to remove lead sulfate crystals). Lead sulfate can also be removed by removing the electrolyte from the battery, then cleaning it with distilled water and filling it with fresh acidic water.
发表回复