News

In the modern logistics and warehousing industry, forklifts, with their high efficiency and flexibility, have become indispensable handling equipment. As the core power source of electric forklifts, the performance and lifespan of lead-acid batteries directly affect the working efficiency of forklifts and the operating costs of enterprises. Scientific and reasonable daily maintenance can not only ensure the stable operation of forklifts, but also effectively extend the service life of batteries and reduce equipment maintenance costs. This article will elaborate in detail on the key points and methods of daily maintenance for forklift lead-acid batteries from multiple crucial aspects.

1. Understand the basic structure and working principle of lead-acid batteries

Before carrying out maintenance work, a thorough understanding of the structure and working principle of lead-acid batteries is fundamental. Lead-acid batteries are mainly composed of positive plates, negative plates, separators, electrolyte, casings and other parts. The active substance on the positive plate is lead dioxide, that on the negative plate is spongy pure lead, and the electrolyte is prepared by mixing sulfuric acid and water in a certain proportion.

Its working principle is based on REDOX reactions. During discharge, the lead on the negative plate reacts with the sulfuric acid in the electrolyte to form lead sulfate and release electrons. Lead dioxide on the positive plate reacts with electrons and sulfate ions under the action of sulfuric acid, generating lead sulfate and water as well. The charging process is the reverse of the discharging process. Under the action of an external power source, lead sulfate is respectively re-converted into lead dioxide and pure lead on the positive and negative plates, and at the same time, the concentration of sulfuric acid is restored. Understanding this principle helps us better recognize the changes of the battery during use, and thus take targeted maintenance measures.

2. Inspection and Preparation before Daily Use

(1) Visual inspection

Before each use of the forklift, the appearance of the lead-acid battery should be carefully inspected. Check whether the battery casing is damaged, cracked or deformed. These conditions may cause electrolyte leakage, which not only corrodes the equipment but also poses safety hazards. At the same time, check whether the battery connection terminals are loose, oxidized or corroded. If the terminal connection is not firm, it will increase the resistance, causing unstable current transmission and affecting the power performance of the forklift. Oxidized or corroded terminals will further aggravate poor contact and may even cause sparks, posing a fire risk. For minor oxidation or corrosion, sandpaper can be used for grinding, and then a special battery terminal protector can be applied. If the situation is serious, the terminals need to be replaced in time.

(2) Check the electrolyte level

Electrolyte is an important medium for chemical reactions in lead-acid batteries. Whether its liquid level is normal or not directly affects the performance of the battery. Batteries with transparent casings allow for direct observation of the liquid level height. For batteries with opaque casings, the liquid injection hole cover needs to be opened for inspection. Under normal circumstances, the electrolyte level should be 10 to 15 millimeters higher than that of the plates. If the liquid level is too low, the plates will be exposed to the air, causing sulfation of the plates and reducing the battery capacity and lifespan. If the liquid level is too high, it may cause the electrolyte to overflow during the charging process. When the liquid level is found to be too low, distilled water or special lead-acid battery replenishment liquid should be added. Do not add tap water, as the impurities in tap water will affect the purity of the electrolyte and the performance of the battery.

(3) Voltage detection

Use a professional battery tester or multimeter to test the static voltage of the battery when the forklift is not started. Batteries of different specifications and models have different static voltages when fully charged. If the voltage is detected to be significantly lower than the standard value, it indicates that the battery power is insufficient and needs to be charged promptly. If the voltage is abnormally low and still cannot return to normal after charging, it may indicate that the battery is faulty and requires further inspection and repair.

3. Precautions during Charging Process

(1) Choose the appropriate charger

Lead-acid batteries have relatively strict requirements for chargers. Different capacities and types of batteries should use chargers that match them. The voltage and current parameters of the charger must comply with the battery specifications. Excessively high voltage or current can lead to overcharging of the battery, accelerate battery aging, and even cause serious problems such as battery heating and bulging. Too low voltage or current will cause the battery to not be fully charged, affecting the battery's performance and lifespan. When purchasing or replacing a charger, be sure to refer to the battery's user manual and choose high-quality products produced by regular manufacturers.

(2) Correct charging environment

During the charging process, it is necessary to ensure that the charging environment is well-ventilated, dry and far away from flammable and explosive items. When lead-acid batteries are being charged, they produce gases such as hydrogen and oxygen. If the ventilation is poor, the accumulation of hydrogen may cause an explosion. A damp environment can easily cause the charger and battery terminals to get damp, increasing the risk of leakage. However, being close to flammable and explosive items may cause serious accidents in case of unexpected situations such as sparks. In addition, the temperature of the charging environment should also be appropriate. Generally speaking, the optimal charging temperature for lead-acid batteries is between 20 and 25 degrees Celsius. Both excessively high and low temperatures can affect charging efficiency and battery life. When the ambient temperature is too high, appropriate cooling measures can be taken, such as using fans for heat dissipation. When the temperature is too low, a charger with temperature compensation function should be used, or charging should be carried out in a warm indoor environment.

(3) Avoid overcharging and undercharging

Both overcharging and undercharging can cause damage to lead-acid batteries. Overcharging can cause the battery to heat up internally, accelerate the aging of the plates and the loss of water in the electrolyte, resulting in a decrease in battery capacity. Undercharging will prevent the lead sulfate on the plates from being fully converted into active substances. Long-term accumulation will lead to irreversible sulfation, which will also affect the battery performance. To avoid overcharging, the charging time should be set reasonably based on the battery capacity and remaining power, and the power supply should be cut off in time after charging is completed. Some modern smart chargers have an automatic stop function when fully charged, which can effectively prevent overcharging. For chargers without this function, the charging process can be controlled by estimating the charging time and combining it with voltage detection. The key to avoiding undercharging lies in timely charging. When the forklift's battery remains at around 20% to 30%, it should be charged. Do not wait until the battery is completely drained before charging.

4. Operating Norms during Use

(1) Avoid high current discharge

When a forklift starts, accelerates and climbs a slope, the instantaneous current is relatively large. Frequent high-current discharges can cause serious damage to lead-acid batteries. Therefore, when operating a forklift, one should start it as smoothly as possible and avoid sudden acceleration and braking. When climbing a slope, if the load is too heavy, the goods can be moved in batches to reduce the discharge current of the battery. In addition, avoiding the continuous use of forklifts for long periods and allowing the battery appropriate rest time can help restore battery performance and extend battery life.

(2) Prevent excessive battery discharge

Over-discharge refers to the situation where a battery is still in use when its power is almost exhausted. This will cause a large amount of lead sulfate to form on the plates and be difficult to be completely converted during subsequent charging processes, resulting in sulfation of the plates and significantly shortening the battery's lifespan. Forklifts are generally equipped with battery level display devices. When the battery level approaches the minimum warning line, use should be stopped immediately and the forklift should be driven to the charging area for charging. If it is impossible to charge in time due to special circumstances, the load should also be reduced as much as possible to lower the depth of battery discharge.

(3) Regular deep discharge

Although excessive discharge should be avoided, regular deep discharge is also beneficial for the maintenance of lead-acid batteries. Deep discharge can activate the active substances on the plates, prevent sulfation of the plates and increase the battery capacity. It is generally recommended to perform a deep discharge every 2 to 3 months. However, it is important to note that a full charge must be carried out promptly after a deep discharge to avoid remaining in a low battery state for a long time.

5. Regular Maintenance and care

(1) Detection and adjustment of electrolyte density

The density of the electrolyte reflects its sulfuric acid concentration and is closely related to the charging and discharging states of the battery. Regularly using a hydrometer to measure the density of the electrolyte can help determine the charging and discharging conditions of the battery and whether the concentration of the electrolyte is normal. Generally speaking, when fully charged, the density of the electrolyte should be around 1.28-1.30g/cm³ (at 25℃), and it will decrease accordingly after discharging. If the density of the electrolyte is detected to be too high or too low, adjustments are required. When the density is too high, distilled water can be added for dilution. If the density is too low, a special sulfuric acid solution needs to be added. However, the adjustment process must be carried out carefully to avoid splashing sulfuric acid and injuring people.

(2) Plate inspection

Regularly open the battery liquid injection hole cover to check the condition of the plates. Observe whether the plates have any deformation, damage, vulcanization or other phenomena. White and hard lead sulfate crystals will appear on the surface of the sulfated plates, resulting in a reduction of the active material on the plates and a decrease in battery capacity. If slight sulfation of the plates is found, it can be repaired by charging with a small current for a long time or using dedicated repair equipment. If the plates are severely deformed or damaged, new plates or the entire battery pack need to be replaced.

(3) Maintenance of battery pack balance

The lead-acid battery of a forklift is usually a battery pack composed of multiple individual cells connected in series. Due to certain differences in performance and capacity among each individual cell, an imbalance may occur during use, that is, some individual cells have a high capacity while others have a low capacity. Long-term imbalance can lead to excessive discharge of individual batteries with low power, accelerating aging and thereby affecting the performance and lifespan of the entire battery pack. Therefore, it is necessary to perform regular equalization charging on the battery pack, that is, to use a dedicated equalization charger to charge each individual battery separately, so that their voltages and capacities are consistent. It is generally recommended to perform equalization charging of the battery pack every 3 to 6 months.

6. Maintenance during Storage and Out-of-use Periods

(1) Short-term storage

If the forklift is temporarily out of use due to holidays or other reasons, the battery should be fully charged before parking and recharged every 3 to 5 days to prevent the battery from self-discharging and causing low power. At the same time, check the appearance of the battery and the connection terminals to ensure there are no abnormal conditions, and park the forklift in a dry and well-ventilated environment.

(2) Long-term storage

When a forklift needs to be stored for a long time, the battery should first be fully charged, and then the connection between the battery and the forklift should be disconnected to prevent the battery from discharging due to the static current of the vehicle during storage. Supplementary charging should be carried out every two weeks, and each charging session should last no less than 8 hours. In addition, during storage, the electrolyte level should be checked regularly, and distilled water or supplementary liquid should be added in time to keep the level normal. Before reusing the forklift, a comprehensive inspection and maintenance of the battery should be carried out, including appearance inspection, voltage detection, electrolyte density detection, etc. Only after ensuring that the battery performance is normal can it be put into use.

7. Safety Precautions

When conducting maintenance work on lead-acid batteries, it is essential to strictly follow the safety operation procedures to ensure personal and equipment safety. First of all, maintenance personnel should wear protective equipment such as acid-resistant gloves and goggles to prevent the electrolyte from splashing onto the skin and eyes. In case of accidental contact with the electrolyte, rinse immediately with plenty of water and seek medical attention promptly. Secondly, when performing operations such as charging and detection, short circuits should be avoided to prevent the generation of sparks that could cause fires or explosions. In addition, discarded lead-acid batteries contain harmful substances such as heavy metals and sulfuric acid. They must be properly disposed of in accordance with environmental protection requirements and must not be discarded at will to avoid environmental pollution.

In conclusion, the daily maintenance of lead-acid batteries in forklifts is a meticulous and important task, covering multiple aspects such as pre-use inspection, charging management, operation, regular maintenance, storage maintenance, and safety protection. Only by strictly following scientific and reasonable maintenance methods and operation norms for maintenance can lead-acid batteries always maintain good performance and a long service life, providing reliable guarantees for the efficient operation of forklifts, thereby reducing the operating costs of enterprises and improving economic benefits.