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In the field of industrial logistics, forklifts, as the core equipment for goods handling, the performance and lifespan of their power source - lead-acid batteries - directly affect the production efficiency and operating costs of enterprises. Adding water for maintenance is an important part of the daily care of lead-acid batteries. Mastering the correct timing and method is the key to ensuring the stable operation of the battery and extending its service life. This article will deeply analyze the key points of water maintenance for forklift lead-acid batteries from multiple dimensions such as principles, judgment methods, and operation procedures.

1. Working Principle of Lead-Acid Batteries and Causes of Water Shortage

The working principle of lead-acid batteries is based on chemical reactions. During the discharge process, lead dioxide at the positive electrode and lead at the negative electrode undergo oxidation-reduction reactions under the action of sulfuric acid solution (electrolyte), generating electrical energy. During the charging process, electrical energy prompts the reaction to proceed in reverse, restoring the battery to its energy storage state. During this charge-discharge cycle, the water in the electrolyte will gradually decrease due to electrolysis and evaporation.

During the electrolysis process, water decomposes into hydrogen and oxygen under the action of electric current and escapes from the battery. At the end of charging, if the current is too large or the temperature is too high, it will also accelerate the decomposition and evaporation of water. In addition, improper usage methods such as frequent deep discharges, overly long charging times, and excessive charging currents will all accelerate the consumption of water. Therefore, regular inspection and replenishment of moisture are necessary operations to maintain the normal operation of lead-acid batteries.

2. Scientific Methods for Judging the Timing of Adding Water

(1) Observe the liquid level of the electrolyte

The lead-acid battery is equipped with a transparent electrolyte observation window or liquid level scale line inside, which is the most intuitive way to judge. Under normal circumstances, the electrolyte level should be maintained between the upper and lower scale lines. When the liquid level is below the lower scale line, it is necessary to replenish water. However, it should be noted that the liquid level scale markings of batteries from different brands and models may vary. Before observation, be sure to consult the battery user manual to understand the accurate liquid level standard.

In addition, some old batteries may not have liquid level scale lines. At this time, the condition of the plates can be observed to make a judgment. If the top of the plate shows the electrolyte and appears grayish-white, it indicates that the electrolyte is seriously insufficient and needs to be replenished immediately.

(2) Test the density of the electrolyte

The density of the electrolyte is closely related to the charging and discharging states of the battery, and it can also reflect the consumption of water. Using a hydrometer to detect the density of the electrolyte is a scientific and precise method. Under normal circumstances, the density of the electrolyte in a fully charged lead-acid battery is approximately 1.28g/cm³ (at 25℃). As water is consumed and the discharge process progresses, the density will gradually decrease. When the density of the electrolyte drops to 1.20g/cm³ - 1.22g/cm³ (with slight variations among different battery models), and combined with the liquid level observation, if the liquid level is also low, water needs to be replenished.

When detecting density, attention should be paid to the influence of temperature. For every 1℃ increase in temperature, the density decreases by approximately 0.0007g/cm³. For every 1℃ decrease in temperature, the density increases by approximately 0.0007g/cm³. Therefore, when conducting the detection, the actual measured density value needs to be converted to the standard density value at 25℃ to ensure the accuracy of the judgment.

(3) Based on the charging time and battery usage frequency

For forklifts with a high usage frequency, such as those that operate continuously for more than 8 hours a day, it is recommended to check the electrolyte level and density once a week. If the usage frequency is low, it can be checked once every two weeks or once a month. At the same time, if it is found that the battery charging time is significantly shortened or a large number of bubbles appear prematurely during the charging process (i.e., the "boiling" phenomenon), this may be due to insufficient electrolyte causing an increase in internal resistance. It is also necessary to check in time and replenish water.

3. The correct water addition operation process

(1) Preparatory work

Before carrying out the operation of adding water, adequate preparations must be made. First of all, it is necessary to ensure that the forklift is in a stopped state, disconnect the battery from the forklift, and prevent short circuits or electric shock accidents during operation. Secondly, prepare appropriate tools and materials, including dedicated distilled water or deionized water (tap water is strictly prohibited as it contains various impurities that can affect battery performance), rubber gloves, protective glasses, funnels, syringes, etc. In addition, rags should also be prepared to clean up the spilled electrolyte in time.

(2) Water addition step

Open the battery cover: The opening methods of the cover vary for different battery models. Some are snap-on, while others are fixed with screws. When opening the upper cover, operate carefully to avoid damaging the upper cover or the internal structure.

Determine the water addition position: Each battery cell has a corresponding liquid addition hole. Make sure to add water to the correct cell.

Slowly add water: Use a funnel or syringe to slowly inject distilled water into each cell of the battery to avoid the electrolyte splashing out due to rapid water flow. During the process of adding water, constantly observe the changes in the water level. When the water level reaches the appropriate position between the upper and lower scale lines, stop adding water. For batteries without liquid level scale lines, it is advisable to add water until it just covers the top of the plates by 2-3mm.

Cleaning and inspection: After adding water, use a cloth to clean the remaining electrolyte on the battery surface and around the liquid filling holes to prevent the electrolyte from corroding the battery casing and other components. Then, carefully check whether the sealing gasket of the upper cover is intact, ensuring that the upper cover is installed properly and sealed well to prevent water evaporation and electrolyte leakage.

(3) Precautions

It is strictly prohibited to add water when the battery is in a high-temperature state. During charging or use, batteries will generate heat. At this time, adding water will cause a sharp change in the temperature of the electrolyte, which may damage the plates and separators and affect the performance of the battery. Water addition should be carried out only after the battery has cooled to room temperature (around 25℃).

After each water addition, the time of water addition, the amount of water added to each cell and the status of the battery should be recorded in a timely manner for subsequent tracking and analysis. If it is found that the water addition in a certain cell is significantly more than that in other cells, it may indicate that there is an internal fault in that cell, such as a short circuit of the plates, and further inspection and repair are required.

Regularly conduct charge and discharge tests on the battery after adding water to observe the performance changes of the battery. If the battery capacity does not increase significantly after adding water, or if abnormal phenomena still occur during charging, professional personnel should be contacted in time for inspection and repair.

4. Handling of Special Circumstances

(1) Electrolyte leakage

If electrolyte leakage is found during inspection or water addition, emergency measures should be taken immediately. First, put on protective equipment, use materials with strong adsorption (such as sand, rags, etc.) to adsorb the leaked electrolyte completely, and then place it in a dedicated container for disposal in accordance with the standards for hazardous waste treatment. It is strictly forbidden to dump it at will. Then, neutralize the leakage area with baking soda or sodium carbonate solution (in a ratio of approximately 1:10). After neutralization, rinse with a large amount of clean water to ensure that the remaining electrolyte is thoroughly removed.

(2) The battery is severely dry

When the electrolyte of a battery dries up severely and sulfation occurs on the plates, simply adding water may not restore the battery's performance. At this point, you can try to adopt the method of "restorative hydration". First, fully charge the battery, then discard the remaining electrolyte. Rinse the interior of the battery repeatedly with distilled water 2 to 3 times to remove sulfides and impurities on the surface of the plates. Finally, add an appropriate amount of distilled water or a dedicated lead-acid battery repair solution, and then charge with a small current (about 1/10 of the battery capacity). The charging time can be appropriately extended to 12-24 hours. After the restorative treatment, observe the performance recovery of the battery. If the effect is not good, it is recommended to replace it with a new battery.

5. Comprehensive Maintenance Suggestions for Extending the Lifespan of Lead-Acid Batteries

In addition to the correct water addition maintenance, taking comprehensive maintenance measures is crucial for extending the service life of forklift lead-acid batteries.

Use batteries reasonably: Avoid over-discharging. When the battery power remains at 20% - 30%, it should be charged in time. Try to minimize operations such as sudden acceleration and sudden braking to reduce the instantaneous high-current discharge of the battery. Avoid using the battery for a long time in high or low temperature environments. When the ambient temperature is too high, you can appropriately increase the charging interval and reduce the charging current. When the ambient temperature is too low, insulation measures can be taken or a charger with low-temperature charging function can be used.

Standard charging operation: Use a charger that matches the battery specifications and charge strictly in accordance with the charger's instructions. Avoid overcharging and undercharging. The charging time should not be too long. Once fully charged, stop charging in time. Regularly inspect and maintain the charger to ensure its stable performance.

Regular inspection and maintenance: In addition to checking the electrolyte level and density, it is also necessary to regularly inspect whether the battery connection wires are loose or oxidized. If poor contact or severe oxidation of the connection wires is found, they should be cleaned and tightened in time. Check if the battery casing is damaged or deformed. If there are any problems, repair or replace it in time.

To sum up, the water addition maintenance of lead-acid batteries in forklifts may seem simple, but it involves many scientific principles and operational skills. Only by accurately grasping the timing of adding water, strictly following the correct operation methods, and combining with comprehensive maintenance measures, can the service life of the battery be effectively prolonged, the working efficiency of the forklift be improved, and the operating costs of the enterprise be reduced. In actual work, forklift operators and maintenance personnel should constantly learn and accumulate experience, combine theoretical knowledge with practical operation, and provide reliable power guarantee for the logistics transportation of enterprises.