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In the field of industrial production, forklifts, as important handling equipment, the performance of their power core - lead-acid batteries - directly affects the working efficiency of forklifts. When forklifts are idle for a long time due to equipment maintenance, seasonal shutdowns and other reasons, the storage of lead-acid batteries becomes a key issue. Incorrect storage methods not only lead to a decrease in battery capacity and a shortened lifespan, but in severe cases, may even cause battery scrapping. So, how should lead-acid batteries for forklifts be stored for a long time? Next, we will introduce to you in detail the scientific and effective storage methods.
Preparations before storage
Before long-term storage of forklift lead-acid batteries, a series of preparatory works are indispensable. First, a comprehensive inspection of the battery should be carried out to check if there is any damage or leakage on the battery casing. If the shell is found to be damaged, even if it is just a tiny crack, it may cause electrolyte leakage during storage, corrode surrounding items and even pose safety hazards. Leakage, on the other hand, will reduce the electrolyte and affect the battery performance. At the same time, use a professional battery tester to measure the battery's voltage and electrolyte density to determine the current performance status of the battery. Under normal circumstances, the voltage of a fully charged lead-acid battery cell should be around 2.1V, and the density of the electrolyte should be 1.28g/cm³ (at 25℃). If the voltage and electrolyte density are significantly lower than the standard values, it indicates that the battery may have a fault and needs to be repaired first.
After the inspection is completed, the battery should be thoroughly cleaned. Wipe the battery casing with a damp cloth to remove surface dust, electrolyte stains and other impurities. These dirt not only affect the appearance but may also form conductive paths on the battery surface, leading to intensified self-discharge of the battery. Special attention should be paid to the battery terminal post area. Use a dedicated terminal post cleaner to remove the oxide, and then apply a thin layer of Vaseline or a dedicated battery terminal post protector to prevent the terminal posts from oxidizing and rusting during storage and ensure good contact between the terminal posts and the connecting wires.
Finally, charge the battery to 100%. A fully charged battery can effectively reduce the occurrence of plate sulfation during storage. Plate sulfation is one of the common faults of lead-acid batteries, which can lead to an increase in battery internal resistance and a decrease in capacity. During the charging process, it is necessary to adopt an appropriate charging current and charging time, and operate strictly in accordance with the requirements of the battery user manual to avoid overcharging or undercharging.
Selection of storage environment
The storage environment is crucial for maintaining the performance of forklift lead-acid batteries. The ideal storage environment temperature should be controlled between 5℃ and 25℃. When the temperature is too high, the rate of chemical reactions inside the battery accelerates, which will speed up the battery's self-discharge and the aging of the plates. If the temperature is too low, it may cause the electrolyte to freeze, damaging the battery casing and plates. For instance, in the hot summer, if batteries are stored in a warehouse exposed to direct sunlight, the temperature may reach over 40℃, and the self-discharge rate of the batteries will significantly increase. After being stored for one month, the battery capacity may decrease by 10% to 15%. In the cold winter, if the battery is placed outdoors, the risk of the electrolyte freezing is extremely high.
At the same time, the storage environment should be kept dry and well-ventilated. A damp environment can cause the battery casing to become damp, increasing the risk of leakage. Moreover, moisture may also enter the battery interior, affecting the composition and performance of the electrolyte. A well-ventilated environment can promptly dissipate the small amount of heat and harmful gases generated by batteries during storage, preventing gas accumulation and potential safety accidents. In addition, it is necessary to avoid storing batteries in places with corrosive gases or liquids, such as near chemical plants or warehouses storing acidic or alkaline substances. These corrosive substances can erode the battery casing and plates, shortening the battery's service life.
Maintenance during storage
Regular maintenance of the battery during long-term storage is the key to ensuring its performance. It is generally recommended to conduct a voltage test on the battery every two weeks. If the battery voltage drops to a certain extent (such as a single cell voltage lower than 2.0V), supplementary charging of the battery is required. The current for supplementary charging should not be too large, usually controlled at around 0.1C (C is the rated capacity of the battery). The charging time depends on the actual condition of the battery, generally ranging from 8 to 10 hours.
In addition, check the electrolyte level every month. During the storage of batteries, a small amount of moisture will evaporate. If the electrolyte level is too low, the plates will be exposed to the air, leading to oxidation and sulfation of the plates. When the electrolyte level is found to be below the lowest mark, distilled water or dedicated lead-acid battery replenishment fluid should be added to restore the level to the normal range. When adding liquid, handle it carefully to avoid splashing and corroding your skin and clothing.
Frequently Asked Questions and Answers
Question 1: Can lead-acid batteries of forklifts be stored without charging maintenance?
No. Even when lead-acid batteries are idle, self-discharge occurs. Long-term non-charging can cause sulfation of the battery plates, seriously affecting the battery's performance and lifespan. During the self-discharge process, the active substances inside the battery gradually undergo chemical reactions and transform into lead sulfate crystals that are difficult to recover and adhere to the plates. Over time, these crystals will accumulate more and more, blocking the micropores of the plates and preventing the electrolyte from fully contacting the plates, thereby reducing the battery's capacity and charge-discharge performance. Therefore, the stored batteries must be recharged at the prescribed time intervals to maintain their activity.
Question 2: When storing lead-acid batteries for forklifts, does the density of the electrolyte need to be adjusted?
Before long-term storage, if the density of the electrolyte does not meet the standard, it needs to be adjusted. For most lead-acid batteries, the density of the electrolyte should be adjusted to 1.28g/cm³ during storage at 25℃. If the density of the electrolyte is too high, it will accelerate the corrosion of the plates. If the density is too low, it may cause the electrolyte of the battery to freeze in a low-temperature environment. When adjusting the density of the electrolyte, a dedicated hydrometer should be used for measurement. Then, based on the measurement results, distilled water or a denser sulfuric acid solution should be added for adjustment. However, it should be noted that the adjustment process must be carried out in a well-ventilated place, and the operators should take protective measures to avoid injury caused by the splashing of sulfuric acid solution.
Question 3: How can batteries that have been stored for a long time be reused?
Batteries that have been stored for a long time should undergo a comprehensive inspection and maintenance before being put back into use. First, check whether the battery casing is intact and whether the terminals are severely oxidized. Then, perform a complete charge and discharge cycle on the battery. When charging, use the normal charging current and charging time to fully charge the battery. When discharging, a dedicated discharge device can be used to discharge the battery according to its rated capacity. Discharge should be stopped when the battery voltage drops to the specified terminal voltage. Through the charge and discharge cycle, the active substances on the battery plates can be activated to restore part of the battery's capacity. If the battery performance remains poor after charging and discharging cycles, further testing and repair of the battery may be necessary, and even battery replacement may be considered.
In conclusion, the long-term storage of lead-acid batteries for forklifts requires adequate preparations, the selection of an appropriate storage environment, and regular maintenance during the storage period. Only in this way can the service life of the battery be effectively prolonged, ensuring that the forklift can operate normally when it is put back into use and reducing the equipment maintenance costs of the enterprise.