UPS battery replacement and maintenance

Hello everyone, I’m Mr. Lin. There is a set of Emerson NXa series 80KVA UPS uninterruptible power supply system in the central computer room of a certain unit. The backup battery is a valve-regulated maintenance-free lead-acid battery, a total of 40 (12V-150AH battery.
At present, the UPS host and battery are running normally, but since the battery pack was put into use in X year X month, the service life has exceeded 3 years. In order to avoid the influence of battery aging on the operation of the UPS host power supply system and the guarantee of UPS backup time, Party A has decided to replace the original 40-section valve-controlled maintenance-free lead-acid battery of the UPS uninterruptible system.
The backup battery of the newly purchased UPS uninterruptible power supply is XX brand and model XX. The technical parameters and specification structure of the new battery fully meet the requirements of the battery in the bidding documents.
On the premise that the mains input of the UPS in the computer room is uninterrupted, disconnect the switch of the UPS host and the battery pack, and then the battery pack can be replaced safely, correctly and efficiently. After the replacement is completed and checked, close the switch of the battery pack to effectively connect the UPS host and the battery pack, and finally carry out UPS debugging and testing to ensure the normal operation of the UPS uninterruptible power system.

Considering that the replacement of UPS backup battery has strict technical, safety and related standards, we must take relevant safety protection measures. The specific implementation process is as follows:

UPS battery replacement and maintenance

2.1 Preparation before implementation

  1. The technicians who implement the battery replacement should go to the computer room for on-site inspection in advance, and communicate with the user’s management personnel about the relevant work: battery arrival, acceptance status, battery placement and other related conditions.
  2. Investigate the location of the UPS host and battery pack in the computer room, and perform technical data registration on the UPS uninterruptible power supply host, battery pack, and UPS host power distribution system. Understanding the relevant technical data of the UPS uninterruptible power supply system will help the battery replacement work.
  3. According to the situation of the survey site, arrange the work of the battery replacement implementation engineers and assistants, and prepare the tools required for the construction such as screw sets, adjustable wrenches, quick wrenches, electrical insulating tapes, transport trailers, multimeters and other related tools .

2.2 Implement battery replacement

  1. After receiving the notification that the battery can be replaced, the battery replacement implementation engineer will go to the site to make preparations: ensure the input power supply of the UPS host, the registration and inspection of the new and old batteries, the sealing of the smoke detectors of the fire protection system in the computer room, and the preparation of carbon dioxide fire extinguishers, etc. related work. Before replacing the battery, make relevant registration records for the UPS host, old battery pack, battery monitor and other equipment, especially the placement of batteries on each layer and the wiring of the battery monitor. Mark and draw connection diagrams. Ensure that the effect of the battery pack after replacement is consistent with the original condition.
  2. After everything is ready, replace the battery, disconnect the connection switch between the UPS host and the battery pack, disconnect the UPS host and the battery pack, and ensure the safety of the staff when replacing the battery. The battery of the original battery pack is disassembled, the battery replacement implementation engineer is responsible for the battery disassembly work, and the relevant auxiliary technicians carry out the transportation of the new and old batteries. When removing the old battery, place the removed battery cable and battery terminal screws neatly in a box to ensure the cleanliness of the equipment room. After removing the old battery, place the old battery and the old battery holder neatly in the position specified by Party A. Place the new battery holder assembly in the designated position, and start to install the new battery at the same time. Place the new battery on the battery holder so that the position and direction of the new battery on the battery holder are adjusted best. After connecting a group of batteries, check whether the connecting wires of the battery terminals are firm; check whether the total voltage of the battery pack is normal, etc., and the positive and negative poles of the battery should be connected correctly.
  3. After replacing the battery, use a multimeter to check the total voltage of the battery pack, the positive and negative poles of the battery pack and the wiring of the neutral wire. After ensuring that the battery pack and the UPS host are normal, turn off the switch of the battery pack to make the UPS uninterruptible power supply system work normally. Then check the working voltage, current, charging voltage, working status of the UPS and make records. One person observes whether the parameters in the LCD screen of the host are consistent with the actual ones, and the battery time parameters are debugged and set to ensure that there will be no wrong alarm prompts during the normal life of the battery. After the UPS host is debugged normally, disconnect the input power switch of the UPS host, simulate the interruption of the mains power failure, and test whether the UPS system can normally switch from the mains power to the battery backup power supply to ensure the normal operation of the equipment in the cabinet of the computer room.
  4. After the battery replacement work is completed, clean the UPS room and clean up the sundries to ensure a good environment for the UPS room. Preparatory work in the equipment room before resuming the battery replacement. Also, the new battery pack should be charged for about 24 hours to ensure that the new battery is fully charged.
  5. Implementation time

Due to the large number of batteries to be replaced, the weight of the batteries is also relatively heavy; and considering the construction conditions on site, the replacement work is difficult to a certain extent, plus the preparation work before installation and the debugging work after installation, it is estimated that the total construction time is about 8 Hour. During the replacement process, the power supply of the UPS host will not be interrupted, and it will not affect the power consumption of other equipment such as the user’s computer room.

  1. Matters needing attention during construction

Be sure to observe the following when installing UPS batteries:

Do not install the UPS battery in a sealed space or near fire, otherwise there is a danger of explosion and fire;

Do not cover the UPS battery with vinyl films that may cause static electricity, as static electricity may sometimes cause an explosion;

Do not install UPS batteries in places where water may enter, otherwise there is a danger of electric shock and fire;

Please do not install the UPS battery in an environment exceeding -40°C~60°C;

Do not use the battery in a dusty place, otherwise it may cause a short circuit of the UPS battery;

When putting the battery into the box, pay attention to the ventilation;

Do not press the top cover with sticky or sticker objects, because there is an exhaust valve under the top cover, the gas generated in the battery will not escape;

The number of parallel connections – during floating charging, the plug-in terminal batteries can only be associated with three columns at most, and there is no special limit for bolt-on terminals, but the reliability is increased when the number of parallel connections is small. In addition, when connecting in parallel, it is necessary to consider equalizing the wiring conductors and contact resistances between each column. In order to keep the charge and discharge batteries of each column balanced, please do not exceed three columns in actual use.

The ups battery is the main component of the entire ups power supply. Once the ups battery stops working, the entire ups power supply can no longer work normally. Therefore, we should pay attention to the precautions for the use of the ups battery during the use of the ups power supply. The precautions for the use of ups batteries are summarized as follows:

  1. Confirm that the conditions of use meet the manufacturer’s specifications.
  2. Be sure to charge it after initial use or long-term use.
  3. The battery used in the UPS is used for floating charge. If the battery is used frequently (similar to cyclic use), the trickle life of the battery will be seriously affected.
  4. Regularly check the battery.
  5. If it is found that the battery is deformed and leaks, please do not use it and replace it.
  6. If the connection at the terminal is not tight, there is a risk of fire.
  7. It is recommended to discharge once every 3 to 6 months if there is no power failure. If the charging voltage or discharge characteristics of the battery are found to be abnormal, please replace the battery.
  8. When the battery capacity is lower than 50% of the initial capacity, the battery should be replaced in time.

Five, the old battery matters needing attention

The replaced old battery should be recycled in time (if there is a leaking battery, special attention should be paid) to avoid the pollution of the human body, equipment and environment caused by the chemical substance of the battery.

  1. Inspection work after battery replacement

Mainly check the following aspects:

  1. On-site environment of UPS main room, battery placement and connection.
  2. The UPS manufacturer’s engineer uses the special software of Emerson UPS equipment to debug and set the battery time parameters of the host to ensure that the battery will not have false alarms during its normal life.
  3. Detect the voltage and current of the input and output of the UPS host; the charging voltage;
  4. Confirm that the UPS host and the battery are in normal operation, and then carry out the mains power failure test to detect the automatic switching of the battery and the battery power supply time.

Through this battery replacement, the safety and reliability of the UPS system have been improved, which are mainly reflected in the following points:

  1. The old battery was replaced, which avoided the potential hidden dangers of the old battery and reduced the failure rate of the UPS host due to battery problems.
  2. When the mains power is interrupted, there will be no power failure of the UPS host. The high performance of the new battery ensures the power supply time of the backup battery of the UPS system.
  3. A good battery pack ensures the normal operation and backup time of the UPS system, and ensures the safe operation of important equipment such as the computer room.
  4. Maintenance after battery replacement
  5. Maintain a suitable ambient temperature. An important factor affecting the battery life is the ambient temperature. Generally, the best ambient temperature required by battery manufacturers is between 20-25 °C. Although the increase in temperature has improved the discharge capacity of the battery, the price paid is that the life of the battery is greatly shortened. According to the test, once the ambient temperature exceeds 25 °C, the life of the battery will be shortened by half for every 10 °C increase.

At present, the batteries used in UPS are generally maintenance-free sealed lead-acid batteries, and the design life is generally 5 years, which can only be achieved in the environment required by the battery manufacturer. If it fails to meet the specified environmental requirements, the length of its life is very different. In addition, the increase of the ambient temperature will lead to an increase in the chemical activity inside the battery, thereby generating a large amount of heat energy, which in turn will increase the ambient temperature. This vicious circle will accelerate the shortening of the battery life.

Second, regular charging and discharging. The float voltage and discharge voltage in the UPS power supply have been debugged to the rated value before leaving the factory, and the size of the discharge current increases with the increase of the load. The load should be adjusted reasonably during use, such as controlling electronic equipment such as microcomputers. number of units used. In general, the load should not exceed 60% of the rated load of the UPS. Within this range, the discharge current of the battery will not be overdischarged.

Because UPS is connected to the mains for a long time, in the environment of high power supply quality and few mains power outages, the battery will be in a floating charge state for a long time, which will lead to a decrease in the activity of the mutual conversion of chemical energy and electrical energy of the battery and accelerated aging. and shorten the service life. Therefore, it should be fully discharged once every 2-3 months, and the discharge time can be determined according to the capacity and load of the battery. After a full-load discharge is completed, recharge for more than 8 hours according to regulations.

  1. Use the communication function. At present, the vast majority of large and medium-sized UPS have operational performance such as communication with microcomputer and program control. Install the corresponding software on the microcomputer, connect the UPS through the serial/parallel port, run the program, and then use the microcomputer to communicate with the UPS. Generally, it has the functions of information query, parameter setting, timing setting, automatic shutdown and alarm.

Through information query, you can obtain information such as mains input voltage, UPS output voltage, load utilization, battery capacity utilization, internal temperature and mains frequency; through parameter settings, you can set the basic characteristics of the UPS, battery maintenance time and Battery run out alarm, etc. Through these intelligent operations, the use and management of the UPS power supply and its batteries are greatly facilitated.

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