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Introduction

In modern logistics and industrial production, forklifts, as important handling equipment, are widely used. As the core power source of electric forklifts, the performance and lifespan of lead-acid batteries directly affect the usage efficiency and operating costs of forklifts. Effective charge and discharge management can significantly enhance the performance of lead-acid batteries, extend their service life, and thereby reduce the overall operating costs of enterprises. Therefore, a thorough understanding and mastery of the charging and discharging management skills of forklift lead-acid batteries are of vital significance for enterprises to achieve efficient, economical and sustainable material handling operations.

1. Charging Management Skills

1.1 Select the appropriate charger

The charging requirements of lead-acid batteries for forklifts of different models and specifications vary. Therefore, it is essential to choose a charger that precisely matches the battery specifications to ensure the safety and efficiency of the charging process. The output voltage and current of the charger should be in line with the rated voltage and charging acceptance capacity of the battery. If the output voltage of the charger is too high, it will cause the battery to overcharge, resulting in excessive consumption of the electrolyte, shedding of the active material on the plates, and shortening the battery life. If the output voltage is too low, the battery cannot be fully charged, causing it to remain in a state of low charge for a long time and accelerating the sulfation of the plates. Similarly, if the output current of the charger is too large or too small, it will also have an adverse effect on the charging effect and lifespan of the battery.

1.2 Strictly control the charging time

Conventional charging time: Generally, the charging time for forklift lead-acid batteries is about 8 to 12 hours. However, this is not a fixed value. The actual charging time needs to be determined comprehensively based on factors such as the battery's depth of discharge, capacity, and the output power of the charger. When the depth of battery discharge is relatively shallow, the charging time can be appropriately shortened. If the depth of discharge is relatively deep, the charging time needs to be extended accordingly.

Avoid overcharging and undercharging: Overcharging can cause the battery to heat up, suffer from severe gas evolution, accelerate the aging of the plates and water loss, and reduce the battery's lifespan. Undercharging will cause sulfation of the battery plates, and the capacity will gradually decrease. To prevent overcharging, a charger with intelligent charging function can be selected. Such a charger can automatically reduce the charging current when the battery is nearly fully charged and enter the trickle charging stage to avoid overcharging of the battery. Meanwhile, the operator should closely monitor the charging status indication of the charger. When the charger shows that the battery is fully charged, stop charging in time. To avoid undercharging, it is necessary to ensure that the forklift is charged in a timely manner after use, and each charge should make the battery fully charged.

1.3 Closely monitor the charging temperature

The influence of temperature on charging: During the charging process, chemical reactions inside the battery generate heat, causing the battery temperature to rise. The suitable charging temperature range is usually 25℃ - 40℃. When the temperature is too high, the chemical reaction rate inside the battery accelerates, and the evaporation of the electrolyte intensifies, which may cause problems such as water loss and plate deformation in the battery. When the temperature is too low, the battery's charging acceptance capacity decreases, the charging efficiency drops, and it is easy to cause local overcharging or undercharging of the battery.

Temperature control measures: To ensure that the battery temperature remains within an appropriate range during the charging process, the following measures can be taken: First, place the forklift in a well-ventilated and relatively stable temperature environment for charging, avoiding charging in high-temperature direct sunlight or cold conditions. Second, when it is found that the battery temperature is too high, charging can be temporarily stopped. Once the battery temperature drops to an appropriate range, charging can resume, or forced air cooling, water cooling and other heat dissipation methods can be used to cool down the battery. Thirdly, some advanced chargers have temperature compensation functions, which can automatically adjust the charging voltage and current according to the ambient temperature to ensure that the battery can achieve good charging effects under different temperature conditions.

1.4 Standardize the charging operation process

Pre-charging inspection: Before starting charging, a comprehensive inspection of the battery and charging equipment is required. Check whether there is any damage or leakage on the battery's appearance, whether the terminals are corroded, and whether the electrolyte level is within the normal range. At the same time, check whether the power cord and plug of the charger are in good condition and whether the charging parameters are set correctly.

Connection sequence: The correct connection sequence is of vital importance. First, firmly connect the output plug of the charger to the charging interface of the battery to ensure that the positive and negative poles are connected correctly. Then, insert the power plug of the charger into the mains socket. After charging is completed, the sequence of disconnecting is reversed. First, unplug the power plug of the charger, and then remove the charging plug on the battery.

Charging process monitoring: During the charging process, the operator must not leave without permission. They should closely observe the working status of the charger and the condition of the battery. Pay attention to whether the indicator light of the charger is showing normally and whether there is any abnormal noise or smell produced. Meanwhile, observe whether the battery has any abnormal phenomena such as overheating or bubbling. If any abnormal situation is found, charging should be stopped immediately and the cause of the fault should be investigated.

1.5 Regularly carry out equalization charging

The necessity of equalization charging: During actual use, due to the possible minor differences in performance and capacity among individual batteries in the forklift lead-acid battery pack, after multiple charge and discharge cycles, these differences will gradually accumulate, leading to overcharging or undercharging of some batteries and affecting the performance and lifespan of the entire battery pack. Equalization charging can make balanced adjustments to each individual battery in the battery pack, making their voltages, capacities and states tend to be consistent, thereby extending the overall service life of the battery pack.

Implementation method: The frequency of equalization charging is generally once every 1 to 2 months, but the specific frequency can be appropriately adjusted according to the battery usage and the manufacturer's suggestions. When performing equalization charging, a dedicated equalization charger or a regular charger with equalization charging function should be used. During the charging process, appropriate charging parameters should be set in accordance with the operation instructions of the charger. Generally, the equalization charging voltage should be slightly higher than the normal charging voltage, and the charging time will also be relatively longer. During the equalization charging process, it is also necessary to closely monitor the battery's temperature and charging status to prevent overcharging or overheating of the battery.

2. Discharge Management Skills

2.1 Prevent excessive discharge

The hazards of over-discharge: Over-discharge refers to the situation where a battery continues to discharge even when its voltage drops below the minimum allowable discharge voltage during the discharge process. Excessive discharge can lead to the formation of a large amount of lead sulfate on the battery plates, and these lead sulfate will form coarse crystals that are difficult to be completely converted into active substances during the subsequent charging process, thereby causing sulfation of the plates, increasing the internal resistance of the battery, reducing its capacity, and seriously shortening the battery's service life.

Control the depth of discharge: To prevent over-discharge, the depth of discharge of the battery should be strictly controlled. Generally speaking, the discharge depth of lead-acid batteries in forklifts should not exceed 80%. Meanwhile, the controller of a forklift is usually equipped with an under-voltage protection function. When the battery voltage drops to the set under-voltage protection value, the controller will automatically cut off the power supply to prevent excessive battery discharge. However, operators should not merely rely on the under-voltage protection function, but should develop the good habit of actively charging when the battery level remains at a certain proportion.

2.2 Avoid high current discharge

The impact of high current discharge: High current discharge will cause the chemical reaction rate inside the battery to accelerate instantaneously, leading to a sharp increase in battery temperature, accelerated shedding of active substances on the plates, and at the same time, it will also cause severe polarization of the battery, increase internal resistance, and further reduce the output voltage and capacity of the battery. If the battery is in a state of high current discharge for a long time, its service life will be significantly shortened.

Reasonable operation of forklifts: During the operation of forklifts, frequent sudden acceleration, sudden braking and long periods of heavy load climbing should be avoided as much as possible. These operations can all cause large current discharge of the battery. For instance, when handling goods, the traveling speed and lifting height of the forklift should be reasonably selected based on the weight of the goods to avoid overloading operations. When starting a forklift, it should be accelerated slowly to avoid pushing the accelerator or control lever to the maximum position instantaneously. During driving, maintain a steady driving pace and avoid frequent starts and stops. In addition, attention should also be paid to the daily maintenance and upkeep of forklifts to ensure the smooth operation of their mechanical components and reduce additional energy consumption and high current discharge caused by mechanical failures.

2.3 Pay attention to the temperature of the discharge environment

The influence of temperature on discharge: Ambient temperature has a significant impact on the discharge performance of forklift lead-acid batteries. In a low-temperature environment, the viscosity of the electrolyte increases, the diffusion rate of ions slows down, and the internal resistance of the battery increases, resulting in a decrease in the battery's discharge capacity. In high-temperature environments, although the discharge capacity of the battery will increase, the excessively high temperature will accelerate the chemical reactions inside the battery, causing the battery plates to age and lose water more rapidly, which will also shorten the battery's service life.

Countermeasures: To reduce the impact of temperature on the battery's discharge performance, when using forklifts in low-temperature environments, measures such as preheating the battery can be taken. For instance, a dedicated battery heating device can be used to raise the battery temperature to an appropriate working temperature range before commencing operations. At the same time, in low-temperature environments, the load and working intensity of the forklift should be appropriately reduced to decrease the discharge current of the battery. When using forklifts in high-temperature environments, it is necessary to ensure that the forklift's heat dissipation system is functioning properly and maintain good ventilation and heat dissipation conditions for the battery. If conditions permit, the forklift can be parked in a shady area to prevent the battery from being exposed to high temperatures for a long time. In addition, it is necessary to pay attention to replenishing the electrolyte of the battery in a timely manner to prevent excessive evaporation of the electrolyte due to high temperature, which may affect the battery performance.

2.4 Regularly carry out deep discharge and activation

The role of deep discharge and activation: Regularly performing deep discharge on forklift lead-acid batteries and then carrying out activation treatment after deep discharge can help remove the slight sulfides that may exist on the plates, restore part of the battery's capacity, and improve the battery's activity and performance. Deep discharge can make more full use of the active substances on the battery plates. Activation treatment can be carried out through specific charging methods or by using activation equipment to promote the reconversion of lead sulfate on the plates into active substances, thereby improving the charging and discharging performance of the battery.

Operation method: The method of deep discharge is generally to discharge the battery to a voltage close to but not exceeding the minimum allowable discharge voltage when the forklift is in normal working condition. After deep discharge is completed, the battery should be activated and charged in a timely manner. Activation charging can be carried out using a dedicated activation charger, and the charging operation should be conducted in accordance with its operation instructions. The activation charging process usually involves multiple stages, such as pre-charging with a relatively small current first, then gradually increasing the current for constant current charging, and finally performing trickle charging, etc., to achieve the best activation effect. The frequency of deep discharge and activation is generally once every 3 to 6 months. The specific frequency can be adjusted according to the battery's usage and actual performance.

3. Conclusion

In conclusion, the charge and discharge management of lead-acid batteries in forklifts is a systematic and meticulous task, covering multiple aspects such as the selection of chargers, control of charging time and temperature, standardization of charging operations, control of discharge depth, avoidance of high current discharge, and attention to the temperature of the discharge environment. By implementing scientific and reasonable charging and discharging management techniques, the performance stability of lead-acid batteries can be effectively enhanced, their service life can be prolonged, and the cost expenditure caused by battery replacement and maintenance for enterprises can be reduced. At the same time, good charging and discharging management also helps to improve the operational efficiency of forklifts and ensure the continuity and stability of production and operation. In the actual operation process, enterprises should strengthen the training of operators, enabling them to master the charging and discharging management skills proficiently, carry out operations strictly in accordance with the operating procedures, and establish a complete battery maintenance and care record file. They should also regularly test and evaluate the performance of batteries to promptly identify and solve problems. With the continuous advancement of technology, the charge and discharge management technology of forklift lead-acid batteries will also be constantly optimized and innovated in the future, providing more powerful support for the efficient production and sustainable development of enterprises.