I. Introduction

In today's highly digital world, whether it is home computers, routers, enterprise servers, precision medical equipment, or automated equipment on industrial production lines, all are highly dependent on stable power supply. Once there is a power anomaly, such as a brief power outage or voltage fluctuation, it may lead to equipment shutdown, data loss, or even serious production accidents or threats to life safety. UPS power supply, as a device that can provide continuous and stable power when the mains power is abnormal, has become a "power bodyguard" for many critical equipment. It is widely used in data centers, medical care, finance, industry, communications, and family sectors, playing an indispensable role in ensuring the normal operation of equipment and data security.

However, the stable operation of UPS power supply is inseparable from scientific and reasonable maintenance, among which discharge maintenance is an extremely critical part. It not only relates to the stable performance of the UPS power supply itself but also directly affects whether the equipment it protects can operate normally at critical moments. But many people still have a vague concept of UPS power supply discharge maintenance and are not clear about the specific operation methods. Next, we will deeply discuss the relevant knowledge of UPS power supply discharge maintenance.

II. What is UPS Power Supply Discharge Maintenance?

UPS power supply discharge maintenance refers to a maintenance measure in the normal operation of UPS power supply, through a specific operation mode, allowing the battery in the UPS power supply to release stored electrical energy, so as to maintain battery performance and ensure the overall operation stability of the UPS power supply. Simply put, it is like giving the battery an "exercise" to keep it in good working condition.

For UPS power supply, the battery is a core component, just like the human heart, providing continuous power support for the entire system when the mains power is abnormal. And discharge maintenance is of great significance for the maintenance and improvement of battery performance. If the battery in a long-term float state is not discharged regularly, the active substances on the battery plates will gradually passivate, and the actual capacity of the battery will gradually decrease, just like people who do not exercise for a long time, their physical functions will slowly decline. Through regular discharge maintenance, the active substances on the battery plates can be activated, so that the battery maintains a high capacity, so that when the mains power is cut off, it can provide more lasting and stable power output.

In addition, discharge maintenance can also help detect the health status of the battery. In the discharge process, we can intuitively observe the battery's discharge time, discharge curve and other parameters to determine whether the battery has problems such as insufficient capacity and excessive performance differences between individual batteries. If problems are found, measures can be taken in time for repair or replacement, avoiding the UPS power supply from failing to work normally due to battery failure at critical moments, ensuring the stability and reliability of power supply, and providing a solid "power backing" for equipment relying on UPS power supply.

III. Why is UPS Power Supply Discharge Maintenance Needed?

(1) Extend Battery Life

The battery in the UPS power supply is in a charged state for a long time, just like a person keeping still, which will cause various problems. Among them, plate sulfation is one of the common problems. When the battery is undercharged for a long time or in a half-discharged state, a layer of white and hard lead sulfate crystals will gradually form on the plates, which is plate sulfation. These crystals will block the micropores of the plates, making it difficult for the electrolyte to penetrate, resulting in an increase in the internal resistance of the battery, a decrease in the utilization rate of active substances, and a subsequent decrease in battery capacity. It is like a person's blood vessels being blocked, poor blood circulation, and physical functions will be affected.

In addition, long-term charging may also lead to the shedding of active substances. During the charging and discharging process of the battery, the plates will continue to expand and contract. Over time, the active substances on the plates may gradually fall off and accumulate at the bottom of the battery. This will not only reduce the effective reaction area of the battery, reduce the battery capacity, but also may cause internal short circuits of the battery and cause more serious faults.

Regular discharge maintenance is like doing exercise for the battery, which can effectively alleviate these problems. During the discharge process, the lead sulfate on the battery plates will be reduced to active substances, thereby reducing the degree of plate sulfation; at the same time, reasonable discharge can make the expansion and contraction of the plates more uniform, reduce the shedding of active substances, and then extend the service life of the battery, ensuring that the UPS power supply can supply power normally at critical moments.

(2) Maintain Stable Power Output

The "memory effect" of the battery will also affect the stability of power output. The "memory effect" usually occurs in rechargeable batteries such as nickel-cadmium batteries. Although most of the current UPS power supplies use valve-regulated sealed lead-acid batteries, the "memory effect" is relatively weak, but it may also have similar problems under long-term irregular use. When the battery is often charged without being fully discharged, the battery will "remember" this incomplete charge-discharge mode, resulting in a gradual decrease in its actual available capacity, just like a person with poor memory always can't remember complete information. With the intensification of the "memory effect", the voltage drop rate of the battery during discharge will accelerate, and the stability of the output power will also be affected, which may not be able to provide continuous and stable power for the equipment.

Through discharge maintenance, the "memory effect" of the battery can be effectively eliminated or reduced. Discharging the battery completely regularly and then fully charging it can make the battery "forget" the previous irregular charge-discharge mode and return to a better working state, thus ensuring that the UPS power supply can stably output power when the mains power is cut off, ensuring the normal operation of the equipment, and avoiding damage to the equipment due to power fluctuations.

(3) Discover Potential Problems in Time

The discharge process is a process of comprehensively testing the performance of the UPS power supply, which can timely find potential problems of components such as the inverter and battery capacity. During discharge, the inverter needs to convert the direct current of the battery into alternating current for output. In this process, if the inverter has potential faults, such as component aging and poor heat dissipation, there may be problems such as abnormal output voltage and waveform distortion. By detecting these parameters, the problems of the inverter can be found in time and repaired or replaced.

At the same time, the discharge process is also an effective means to detect battery capacity. By recording parameters such as the discharge time, discharge current, and voltage at the end of discharge of the battery, the actual capacity of the battery can be accurately calculated. If it is found that the actual capacity of the battery is significantly lower than the nominal capacity, it indicates that the battery may have problems such as aging and damage, which need further inspection and treatment. For example, when a data center performed discharge maintenance on the UPS power supply, it found that the discharge time of a group of batteries was nearly half shorter than the normal situation. After detailed testing, it was found that several of the batteries had serious problems of plate sulfation and active material shedding. After replacing these batteries in time, the performance of the UPS power supply returned to normal, avoiding the data center paralysis caused by battery failure when the mains power was cut off.

IV. How to Perform UPS Power Supply Discharge Maintenance?

(1) Preparation Before Discharge

1. Understand UPS power supply parameters: Different models of UPS power supplies have different parameters such as rated capacity and backup time, which are important bases for formulating discharge plans. Take a UPS power supply with a rated capacity of 10KVA as an example, its backup time may vary due to the number and type of configured batteries. Only by clearly understanding these parameters can we accurately judge the performance and state of the battery during the discharge process and ensure the safety and effectiveness of the discharge operation.

2. Check equipment status: Before discharge, it is crucial to carefully check the appearance of the battery. Check whether the battery case is deformed, bulging, cracked, etc. If these problems are found, it indicates that the battery may have internal faults and needs further inspection or replacement. For example, when obvious bulging is found on the battery case, it is likely that gas accumulates inside the battery, which will affect the normal performance and safety of the battery.

At the same time, use a professional battery tester to detect the battery voltage to ensure that it is within the normal range. Generally speaking, a common 12V lead-acid battery should have a voltage of about 13.5V - 13.8V when fully charged; if the voltage is significantly low, it may mean that the battery is undercharged or damaged.

It is also necessary to check whether the connecting lines are firm and whether there are problems such as looseness and oxidation. Loose lines may lead to an increase in contact resistance, which may cause heat, sparking and other dangerous situations during discharge; oxidized lines will affect current transmission and reduce the performance of the UPS power supply. In addition, check the load equipment connected to the UPS power supply to ensure that it is running normally, so as to avoid affecting the discharge operation or damaging the equipment due to the failure of the load equipment.

1. Formulate a discharge plan: Reasonably formulate a discharge interval (such as once every 1 - 3 months) according to factors such as the use environment of the UPS power supply, and control the discharge amount to 20% - 30% of the rated capacity. If the use environment of the UPS power supply is relatively harsh, such as places with high temperature, high humidity or much dust, the discharge interval should be appropriately shortened to ensure the performance of the battery; for UPS power supplies that are used frequently, more frequent discharge maintenance is also required. Controlling the discharge amount within this range can not only achieve the purpose of maintaining the battery but also avoid damage to the battery due to over-discharge.

(2) Discharge Operation Steps

1. Safely cut off the load: Before performing the discharge operation, be sure to turn off all electronic equipment connected to the UPS power supply and unplug the equipment plug. This is because during the discharge process, the output voltage and current of the UPS power supply may fluctuate. If the load equipment is not powered off, these fluctuations may damage the equipment, leading to equipment failure or data loss. For example, if a computer suddenly loses power during the discharge process, it may cause hard disk damage, file loss and other problems.

2. Switch to discharge mode: Different brands and models of UPS power supplies have different operation methods to enter the discharge mode. Some small UPS power supplies may only need to press the "test" button on the machine to enter the discharge mode; while large UPS power supplies may need to operate the control panel, select the "discharge test" option in the menu, and then confirm the operation according to the prompts to start discharge. Before operation, be sure to carefully read the user manual of the UPS power supply to ensure correct operation.

3. Monitor the discharge process: During the discharge process, the discharge status can be monitored in real-time through the LED indicator, LCD display or monitoring software of the UPS power supply. Pay close attention to changes in parameters such as voltage, current and remaining power. Under normal circumstances, as the discharge proceeds, the battery voltage will gradually decrease and the current will remain relatively stable. If it is found that the voltage drops too fast or the current increases abnormally, it may mean that there is a problem with the battery, and it is necessary to stop the discharge immediately and conduct an inspection. For example, when it is found that the battery voltage drops sharply in a short time, it may be that there is a short-circuit fault inside the battery.

4. Control the depth of discharge: It is very critical to strictly control the discharge amount to about 20% - 30% of the rated capacity. Over-discharge will aggravate the sulfation of the battery plates, shorten the battery life, and even make the battery irreparable. When it is monitored that the remaining power of the UPS power supply reaches the predetermined discharge depth, the discharge operation should be stopped immediately, and the UPS power supply should be switched back to the mains charging mode. The monitoring software of the UPS power supply or the discharge termination parameters on the control panel can be set. When the power reaches the set value, the system will automatically issue an alarm and stop the discharge.

(3) Post-Discharge Processing Work

1. Restore mains power supply: After the discharge is completed, switch the UPS power supply back to mains power supply. First, ensure that the mains power is normal and stable, then switch it from the discharge mode to the normal working mode according to the operation instructions of the UPS power supply, which is generally done by operating the corresponding buttons or menu options on the control panel. During the switching process, pay attention to observe the working status of the UPS power supply to ensure that the switching is successful and that the mains power can normally supply power to the UPS power supply and load equipment.

2. Check the equipment status: Check the status of the battery, UPS power supply and load equipment again. Check whether there are abnormal changes in the appearance of the battery, measure the battery voltage, and confirm whether it is within the normal charging range; check the operating parameters of the UPS power supply, such as output voltage and current, to see if they are normal and stable; perform power-on tests on the load equipment to ensure that it can work normally after the mains power is restored. If any abnormal situation is found, the cause should be analyzed and dealt with in time.

3. Record discharge information: Record in detail the discharge time, discharge amount, equipment status and other information. These records are very important for subsequent maintenance work, which can help technicians analyze the performance change trend of the UPS power supply and battery and find potential problems in time. For example, by comparing discharge records in different periods, if it is found that the discharge time of the battery is gradually shortened, it may mean that the battery performance is declining, and further inspection and maintenance are required. The recorded information can be in the form of paper forms or electronic documents for easy storage and review.

V. Precautions for UPS Power Supply Discharge Maintenance

(1) Environmental Requirements

UPS power supply discharge maintenance has strict requirements on environmental conditions. In terms of temperature, generally, the suitable working environment temperature for the UPS power supply host is in the range of 0 - 30℃, and there may be slight differences among different brands. Some small UPS power supply heads require a temperature of 0 - 40℃, and some large UPS power supplies are 0 - 35℃, while the optimal operating temperature for storage batteries is 25℃, and it is recommended to keep it at 15 - 30℃. If the ambient temperature is too high, it will accelerate the aging of the battery plates, intensify the chemical reaction inside the battery, generate excessive heat, further affect the battery performance, and even cause the inverter to stop working and alarm; too low temperature will increase the viscosity of the battery electrolyte, increase the internal resistance, reduce the output capacity, and make the actual discharge capacity far lower than the nominal capacity, which cannot provide stable and sufficient power for the equipment. For example, in hot summer, if the UPS power supply is placed in a room without air conditioning and poor ventilation, the battery temperature may rise rapidly during discharge maintenance, affecting its service life and performance.

Humidity is also a key factor. Take the storage battery commonly used in UPS power supply as an example, it is suitable to work in an environment with humidity of 5% - 95% without frost. If the environmental humidity is too high, reaching more than 80%, the surface of the storage battery is easy to condense, which may cause serious faults such as short circuit and damage the equipment; if the humidity is too low, less than 30%, it is easy to generate static electricity, which may interfere with the normal operation of the UPS power supply and cause damage to electronic components. For example, in a humid basement or coastal area, the high humidity environment will have an adverse impact on the discharge maintenance of the UPS power supply, and dehumidification measures need to be taken to ensure the safety of the equipment.

Ventilation is also not to be ignored. The UPS power supply uses a fan for forced air cooling, so it is necessary to ensure that there is enough space reserved around the cabinet to ensure good ventilation and heat dissipation. At the same time, the storage battery will produce a small amount of hydrogen and oxygen at the end of charging. If the ventilation is not smooth, these gases may accumulate and cause an explosion and other dangers. Therefore, the UPS power supply should be placed in a well-ventilated place, away from closed and narrow spaces and ventilation dead corners, to create safe environmental conditions for discharge maintenance.

(2) Operation Specifications

It is crucial to strictly carry out the discharge operation in accordance with the operation manual, which is directly related to the safety and normal operation of the equipment, and avoids equipment damage or safety accidents caused by misoperation. Before carrying out the discharge operation, the operator must carefully read and be familiar with the operation manual of the UPS power supply, and understand the various functions, operation procedures and precautions of the equipment. Different brands and models of UPS power supplies have different operation methods and steps, such as entering the discharge mode, setting parameters, monitoring status and other operations. For example, a certain brand of UPS power supply needs to press a specific combination of keys on the control panel in turn and enter the password to confirm to enter the discharge mode; while another brand operates and sets through the software interface. Failure to operate in the correct way may lead to failure to discharge normally or put the equipment in an abnormal working state, damaging the battery or other components.

During the operation, ensure that the actions are standardized and accurate to avoid problems caused by misoperation. For example, when switching loads or setting parameters, be careful to prevent accidental touching of other buttons or selecting wrong options. At the same time, it is strictly forbidden to carry out dangerous operations such as live plugging and short circuit on the equipment during the discharge process, so as to avoid electric shock, fire and other safety accidents, and cause serious harm to personnel and equipment.

(3) Emergency Treatment

During the discharge process, various emergencies may be encountered, such as UPS power supply failure, power outage, etc. It is crucial to master the correct emergency treatment measures. In case of UPS power supply failure, first keep calm and quickly judge the type and severity of the failure. If it is a general failure, such as abnormal individual indicators, slight alarm, etc., you can gradually check each part of the equipment according to the fault troubleshooting guide in the operation manual, such as whether the battery connection is loose, whether the line is damaged, whether the module is overheated, etc., and try to find the cause of the fault and repair it. If the fault is serious, such as the UPS power supply stops working completely, gives a strong alarm, etc., the discharge operation should be stopped immediately, and the connection between the load and the UPS power supply should be disconnected to prevent the fault from expanding and affecting the load equipment. At the same time, contact professional maintenance personnel in time and describe the fault phenomenon and operation process in detail to them, so as to quickly locate and solve the problem.

When a power outage occurs during the discharge process, corresponding measures should be taken according to the specific situation. If the UPS power supply is in a normal discharge state and the battery power is sufficient, you can continue to observe the operation of the equipment to ensure that it can normally supply power to the load. But pay close attention to the change of battery power. When the power is close to the discharge termination value, non-critical loads should be turned off in time to give priority to ensuring the operation of important equipment. If the UPS power supply has failed or the battery power is insufficient during the power outage, the backup power supply, such as a generator set, should be started immediately, and the key equipment should be switched to the backup power supply to ensure the normal operation of the equipment. At the same time, do a good job in data backup to prevent data loss due to power interruption. In the process of emergency treatment, keep the communication unblocked, report the situation to superiors and relevant personnel in time, and solve the problem together to ensure the stability of power supply and the safety of equipment.

VI. Summary

UPS power supply discharge maintenance is a key maintenance measure to ensure the performance of UPS power supply and extend the battery life, and occupies a pivotal position in the entire UPS power supply maintenance system. Through regular discharge maintenance, it can effectively extend the battery life and avoid problems such as plate sulfation and active material shedding caused by long-term charging; maintain stable power output, eliminate or reduce the "memory effect" of the battery, and ensure stable power supply for equipment when the mains power is cut off; it can also timely find potential problems in the inverter and battery capacity of the UPS power supply, repair or replace them in advance, and ensure the reliability of power supply.

When carrying out discharge maintenance, strictly follow the standardized operation process. Before discharge, fully understand the UPS power supply parameters, carefully check the equipment status, and carefully formulate a scientific and reasonable discharge plan; during the discharge process, safely cut off the load, correctly switch to the discharge mode, closely monitor the discharge status, and accurately control the discharge depth; after the discharge, timely restore the mains power supply, check the equipment status again, and record the discharge information in detail.

At the same time, the precautions in the discharge maintenance process cannot be ignored. It is necessary to create suitable environmental conditions for the UPS power supply, strictly control the temperature, humidity and ventilation; operators must strictly follow the operation manual to avoid misoperation; and master the emergency treatment methods in advance, so that they can quickly and properly deal with emergencies such as UPS power supply failure and power outage.

Only by fully understanding the importance of UPS power supply discharge maintenance, effectively mastering the correct operation methods and precautions, and carrying out discharge maintenance regularly and standardizedly, can we ensure that the UPS power supply is always in good operating condition, provide continuous, stable and reliable power guarantee for key equipment in data centers, medical care, finance, industry, communications, and families, and effectively avoid serious consequences such as data loss, equipment damage, and production accidents caused by power abnormalities.