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1. Introduction

Forklifts, as indispensable and important equipment in modern logistics and warehousing industries, mainly rely on lead-acid batteries for their power sources. The performance and reliability of lead-acid batteries directly affect the working efficiency and operational safety of forklifts. However, during long-term use, lead-acid batteries are bound to encounter various faults. A thorough understanding of the fault diagnosis and elimination methods for lead-acid batteries in forklifts is of vital significance for ensuring the normal operation of forklifts, reducing maintenance costs, and enhancing the production efficiency of enterprises.

2. Common Fault Types and Diagnostic Methods of Lead-Acid Batteries in Forklifts

(1) The battery power is insufficient

1. ** Fault Phenomenon ** : The forklift has difficulty starting, the motor power is significantly weakened, and the battery level indicator light on the dashboard shows a low battery level. Even after a long period of charging, the battery level still cannot reach the normal level.

2. **Diagnostic Methods**

- ** Measure voltage with a multimeter ** : Disconnect the battery from the forklift circuit, set the multimeter to the DC voltage range, and measure the voltage across the battery terminals. Under normal circumstances, the voltage of a fully charged 12V lead-acid battery should be around 12.6 to 12.8V. If the measured voltage is significantly lower than this range, it indicates that the battery power is insufficient.

- ** Check the charging system ** : Inspect whether the charger is working properly, check if the input voltage of the charger is stable, and whether the output voltage and current meet the charging requirements of the battery. At the same time, check whether there is any damage, short circuit or poor contact in the charging circuit. This can be judged by visual inspection and using a multimeter to check the continuity of the circuit.

(2) Battery leakage

1. ** Fault Phenomenon ** : There are damp marks on the surface of the battery casing, or white or green crystalline substances adhere to it. The electrolyte has decreased, and at the same time, a pungent smell of sulfuric acid may be detected.

2. **Diagnostic Methods

- ** Visual Inspection ** : Carefully inspect the battery casing for any cracks or damages, especially at the connection between the upper cover and the casing, as well as around the terminals. If liquid leakage or crystalline substances are found, it indicates that there is a leakage phenomenon.

- ** Pressure test ** : For batteries where it is difficult to directly observe the leakage point, the pressure test method can be adopted. Place the battery in a sealed container and slowly fill the container with gas at a certain pressure (the pressure should not be too high to avoid damaging the battery). Then observe whether there are bubbles emerging on the surface of the battery. The location of the bubbles is the leakage point.

(3) Sulfation of battery plates

1. ** Fault Phenomenon ** : When the battery is charging, the voltage rises too fast, bubbles form prematurely, and the temperature of the electrolyte increases significantly; During discharge, the voltage drops rapidly and the capacity decreases significantly.

2. **Diagnostic Methods

- ** Observe the condition of the plates ** : Open the upper cover of the battery, remove the plate group, and observe the surface of the plates. If there are white and hard lead sulfate crystals on the surface of the plates and they are difficult to be filled off by common methods, it indicates that the plates have been vulcanized.

- ** Measure the density of the electrolyte ** : Use a hydrometer to measure the density of the electrolyte and compare it with the standard value. If the density of the electrolyte is significantly lower than the standard value and the density increases slowly or not at all during the charging process, it may also be caused by sulfation of the plates.

(4) Internal short circuit of the battery

1. ** Fault Phenomenon ** : The battery overheats severely during charging, the voltage does not rise, and almost no bubbles are produced; When discharging, the power is rapidly depleted.

2. **Diagnostic Methods**

- ** Voltage Measurement Method ** : Measure the voltage of each cell of the battery separately. If the voltage of a certain cell is significantly lower than that of the others, it indicates that there may be an internal short circuit in that cell.

- ** Current Detection method ** : During the charging process of the battery, measure the charging current. If the charging current is too large and the voltage does not rise, it can be initially determined that there is an internal short circuit. Further, by disconnecting the battery from the charger and measuring its self-discharge current, if the self-discharge current is too large, it can also indicate an internal short circuit problem.

(5) Poor contact of the pole posts

1. ** Fault Phenomenon ** : When the forklift starts, there may occasionally be a situation where the motor rotates weakly or does not rotate at all. The voltage display on the instrument panel is unstable, and sometimes there is a sudden drop in voltage.

2. **Diagnostic Methods**

- ** Visual inspection ** : Observe whether there are any signs of loosening, oxidation or ablation at the connection between the terminal post and the connecting wire. If there are black or green oxides on the surface of the terminal post, it will affect the electrical conductivity.

- ** Resistance Measurement ** : Use the resistance range of a multimeter to measure the contact resistance between the terminal post and the connecting wire. Under normal circumstances, the contact resistance should be very small (close to 0Ω). If the measured resistance is relatively large, it indicates poor contact of the terminal post.

3. Troubleshooting Methods for Lead-Acid Batteries in Forklifts

(1) Troubleshooting for insufficient battery power

1. ** Supplementary charging ** : If the battery power is insufficient due to normal power consumption, a suitable charger can be used for supplementary charging of the battery. According to the instructions of the charger, set the correct charging voltage and current. Generally, a constant voltage and limited current charging method is adopted. First, perform rapid charging with a relatively large current. When the voltage reaches a certain value, switch to constant voltage charging until the battery is fully charged.

2. ** Repair the charging system ** : If any malfunction is found in the charging system, such as a damaged charger, a charger of the same model and specification should be replaced in a timely manner; For the charging line issue, repair the damaged lines, reconnect the loose joints, and ensure that the charging lines are firmly connected and have good contact.

(2) Elimination of Battery Leakage

1. ** Minor Leakage Repair ** : If the leakage is caused by minor cracks in the battery casing, it can be repaired with a dedicated battery repair adhesive. First, clean the leaking area thoroughly, remove the electrolyte and impurities on the surface, then apply repair glue. After the glue has cured, check if the leakage has improved.

2. ** Severe Leakage Treatment ** : For leakage caused by severely damaged casing or poor sealing of terminal posts, it is generally necessary to replace the battery with a new one. When replacing the battery, it is necessary to pay attention to choosing a product of the same model as the original one to ensure that its voltage, capacity and other parameters meet the requirements of the forklift. At the same time, install the new battery correctly and connect the positive and negative terminals properly to avoid reversing them.

(3) Elimination of sulfation on Battery plates

1. ** Small Current charging method ** : For plates with mild vulcanization, a method of long-term charging with a small current can be adopted for repair. Adjust the charging current to 1/10-1/5 of the normal charging current, and charge continuously for 10-20 hours. Then stop charging for 1-2 hours and charge again. Repeat this process until the lead sulfate crystals on the surface of the plates gradually dissolve.

2. ** Chemical Repair Method ** : Use a specialized plate vulcanization repair agent. According to the requirements of the manual, inject the repair agent into the battery and then charge it normally. The chemical components in the repair agent can react with lead sulfate, converting it into a soluble substance, thereby achieving the purpose of repairing the sulfation of the plates.

(4) Elimination of Internal short circuits in the battery

1. ** Check the cause of the short circuit ** : If the internal short circuit is caused by reasons such as bent plates or shedding of active materials, the battery casing needs to be opened, and the plate assembly carefully inspected to identify the exact location of the short circuit. For the case of plate bending, correction can be carried out carefully. For short circuits caused by the shedding and accumulation of active substances, the shed substances need to be cleared.

2. ** Replace damaged parts ** : If the short circuit is caused by the damage of the partition, a new partition should be replaced. When replacing the partition board, it is necessary to pay attention to choosing a product of good quality and appropriate size, ensure correct installation, and prevent short circuit problems from happening again. If the internal short circuit of the battery is severe and cannot be repaired, the entire battery needs to be replaced.

(5) Elimination of Poor Contact of the terminal posts

1. ** Remove Oxide ** : Use sandpaper or a special metal brush to clean the oxide off the surface of the terminal post and the connection wire joint, revealing the metallic luster. After cleaning, a layer of conductive paste can be applied to the surface of the terminal post and the joint to enhance the conductive performance.

2. ** Tight connection ** : Use appropriate tools to firmly install the connection wire joint on the terminal post, ensuring a tight connection without any looseness. Regularly check the connection of the terminal posts to prevent loosening due to vibration or other reasons.

4. Measures to Prevent Faults of Lead-Acid Batteries in Forklifts

1. ** Correct usage ** : Operate strictly in accordance with the user manual of the forklift and the battery to avoid excessive discharge. When the battery power drops to a certain level, it should be charged in time. At the same time, avoid high-current discharges, such as frequent sudden acceleration and sudden braking operations, as they can cause damage to the battery.

2. ** Regular Maintenance ** : Regularly check the electrolyte level of the battery. When the electrolyte is insufficient, add distilled water or special lead-acid battery replenishment fluid to keep the liquid level within the specified scale range. Regular charge and discharge maintenance should be carried out on the battery. Generally, a complete charge and discharge should be performed every 2 to 3 months to activate the active substances on the plates and extend the service life of the battery.

3. ** Environmental Control ** : Place the battery in a dry and well-ventilated environment to avoid the influence of moisture, high temperature and corrosive gases on the battery. In winter, it is necessary to keep the battery warm to prevent the electrolyte from freezing. In summer, avoid exposing the battery to the sun for a long time to prevent excessive temperature from affecting its performance.

4. ** Cleaning and Maintenance ** : Regularly clean the dust, electrolyte and other dirt on the surface of the battery casing to keep it clean and dry. At the same time, check the terminals and connecting wires of the battery to ensure that the connection parts are clean and free of oxidation.

5. Conclusion

Fault diagnosis and elimination of lead-acid batteries in forklifts is a complex and meticulous task, which requires maintenance personnel to have solid theoretical knowledge and rich practical experience. By having a thorough understanding and accurate diagnosis of common fault types, adopting effective elimination methods, and doing a good job in daily preventive maintenance, problems with the battery can be solved in a timely manner, its service life can be prolonged, the normal operation of forklifts can be ensured, and reliable power support can be provided for the production and operation activities of enterprises. With the continuous development of technology, the performance of lead-acid batteries in forklifts will keep improving in the future. The methods for fault diagnosis and elimination will also become more intelligent and convenient. Maintenance personnel need to constantly learn and update their knowledge to meet the development needs of the industry.