lithium 3400mah 3.7v 18650 battery.UPS battery maintenance status and solutions

　　In an uninterruptible power supply (UPS) system, it can be said that the battery is the backbone of the system. A UPS without a battery can only be called a regulated voltage and frequency (CVCF) power supply. UPS can achieve uninterrupted power supply because of the battery. When the mains power is abnormal, the inverter directly converts the chemical energy of the battery into AC power and transmits it, so that the electrical equipment can continue to operate.

　　At present, the maintenance-free sealed lead-acid batteries widely used in small and medium-sized UPS power supplies account for 1.4-1.2 of the total cost of UPS power supplies. Not only that, actual maintenance also shows that more than 50% of UPS power supplies fail. Related to UPS batteries. The main manifestations of UPS battery failure are insufficient terminal voltage, insufficient capacity or instantaneous discharge current that does not meet the load starting requirements.

　　Generally, the battery life of a UPS in normal use is about 5 years. However, currently a considerable number of UPS batteries in China begin to have problems less than one year after being put into use. What's more, some imported brands of domestic batteries have defects in the manufacturing process. Congenital defects, on the other hand, are caused by lack of necessary maintenance. It is worth noting that many users have no idea about the health status of their own system's UPS batteries due to the lack of necessary testing and maintenance methods, leaving hidden dangers for the normal operation of the UPS system.

　　1. Traditional UPS battery testing and maintenance methods

　　General UPS power supply requirements for batteries: meet a certain terminal voltage; the battery should have the characteristics of being able to output a large current at the moment of starting discharge; meet a certain capacity to ensure the time of inverter power supply.

　　1. Use a multimeter to measure the terminal voltage of the battery

　　Practice has proved that it is impossible to determine whether the old battery has expired by measuring the floating charge terminal voltage of the UPS battery with a multimeter. Therefore, it is generally necessary to measure the terminal voltage of the battery offline or online. The terminal voltage of the battery under test is about 12V (for a 12V battery), and the minimum cannot be lower than 10.5V. A battery with less than 10.5V is undervoltage or has expired. If the battery's terminal voltage still does not reach 12V after charging or activating charging, it is a failed battery.

　　2. Test whether the UPS battery has the characteristics of outputting large current at startup

　　The switching time of the backup UPS power supply from the mains power supply to the inverter power supply is required to be less than 7ms? The general design is about 4-5ms. This means that once the mains power supply is interrupted, the UPS battery must output the current required by the load in less than 4-5ms. Some failed batteries can meet the terminal voltage and capacity requirements, but if the discharge current cannot reach the high current requirement in less than 4-5ms, they are also unqualified batteries. The UPS battery's characteristic of instantaneously outputting large current can only be tested when the mains power is turned off. There are certain risks without knowing the battery performance, so it is generally not carried out. The UPS battery cannot output enough current in an instant. This is generally caused by the battery not being discharged for a long time. This problem basically does not exist for UPS batteries that are frequently discharged or discharged regularly.

　　3. Determine the capacity of UPS battery

　　The traditional method of judging UPS battery capacity is the same as the method of judging ordinary batteries. The entire battery pack is separated from the communication power supply system and a resistance wire is installed. It discharges at a constant current at a rate of eight or ten hours, and then discharges the battery at a certain rate that reaches the discharge end voltage first. The discharge time and current of a single battery are used to calculate its capacity.

　　Traditional capacity testing has the following disadvantages:

　　a. The battery pack needs to be disconnected from the system, which increases the risk of system crash;

　　b. The discharge time is long and requires manual testing and recording, which requires a lot of work. In addition, UPS batteries are generally installed in box-type cabinets, and the testing work is not very easy;

　　c. Resistance wire is bulky and red-hot, unsafe and requires a lot of work.

　　2. Current status of domestic UPS battery maintenance

　　The maintenance of UPS batteries is similar to the maintenance of batteries in general low-voltage systems. When a new battery is introduced, it requires project acceptance and deep discharge; when a new battery is put into use, it is required to maintain a suitable battery working environment temperature and regularly measure the terminal voltage of each battery. , when the voltage difference between each battery is too large, equal charging is required, and exploratory capacity tests or deep discharges of the batteries are required on a regular basis in order to check the performance of the battery pack and maintain the activity of the battery.

　　However, in actual use, due to various conditions, few people perform UPS battery maintenance exactly as described above. First, the acceptance of new batteries takes a long time and there are no convenient tools to use. Quite a few people do not have it at all. To do this work, the battery is put into use. According to statistics, more than 95% of UPS batteries in mainland China lack necessary maintenance, which lays hidden dangers for future UPS power supply failures. Secondly, after the new battery is put into use, due to the general UPS battery failure It is installed in a cabinet, making it inconvenient to measure and detach. The terminal voltage is rarely measured, and regular deep discharge is impossible. According to the existing conditions (more than 98% of UPS batteries are not equipped with monitoring equipment), the majority of maintenance personnel can Only every once in a while, turn off the mains power and let the UPS battery discharge the actual system for a period of time. At best, it just activates the battery pack to maintain the activity of the battery, but it is important for the performance of the battery and the remaining capacity of each battery. The data is still unknown.

　　3. Comprehensive solution for UPS battery maintenance

　　This solution consists of three products: BCSU-50HUPS battery pack capacity monitoring equipment, MBCT-2412UPS single battery online charge and discharge activator, and BDCT-5000UPS battery dedicated smart load.

　　1. BCSU-50HUPS battery pack capacity monitoring equipment

　　It can monitor and record the float voltage, current and charge and discharge voltage and current of the UPS battery online; BCSU can judge the performance of the battery pack, find out the lagging cells and provide information as long as the discharge data for more than 5 minutes is recorded online. The remaining capacity of each cell not only avoids the trouble and unsafety of offline capacity testing, but also achieves the purpose of capacity testing; when the voltage difference in a group of batteries is measured to be large, a signal for equalizing charging will also be given; BCSU can also cooperate with smart load BDCT to carry out engineering acceptance of new batteries or perform deep discharge regularly. Here BDCT provides discharge current, and BCSU mainly plays a monitoring and alarm role to avoid over-discharge of any single unit. In addition, BCSU will automatically generate a test report. Saves you a lot of work.

　　2. MBCT-2412UPS single battery online charge and discharge activation instrument

　　For backward single cells found by BCSU, charge and discharge online (without affecting the normal operation of other batteries in the entire group) to activate failed active materials, reduce internal resistance, compensate for voltage differences and replenish remaining capacity to avoid further damage to the backward single cells. Deterioration and affect other cells, that is, early treatment and prevention of the battery. In addition, MBCT can be used to conduct in-depth online capacity tests on lagging single cells (without affecting the normal operation of other batteries in the entire group), so that the cell can be accurately known The unit is the capacity of the entire battery pack (the smallest backward single unit determines the capacity of the entire battery pack).

　　3. BDCT-5000UPS battery-specific intelligent load

　　Newly introduced UPS batteries must be deeply discharged to check whether their capacity is qualified, whether there are process defects in the battery, etc. In addition, batteries with a long service life must also be deeply discharged to avoid phenomena such as system paralysis caused by insufficient instantaneous starting current. . Deep discharge can only be done by disconnecting the battery from the system and using a dummy load. The dummy load made of traditional resistance wire has obvious shortcomings; BDCT-5000UPS battery-specific smart load uses the latest patented material - high-efficiency electric heating element PTC, which is lightweight, portable, and has no red hot phenomenon. In addition, it has three shutdown thresholds: total voltage, discharge capacity, and discharge time. If used with BCSU, each unit can be controlled, and unattended discharge can be achieved, greatly reducing labor intensity. In this way, the problem of wanting to do deep discharge but being unable to do so is well solved.

　　These three products work together to solve the problem of the current lack of necessary maintenance methods and tools for UPS batteries. They can not only test battery performance for you and find outdated cells, but also help you activate outdated batteries and perform early treatment on batteries? Effectively? Prevent failures from occurring.

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