How to reduce the failure rate of UPS battery

How to reduce the failure rate of UPS battery

Regularly check the terminal voltage and internal resistance of each cell battery. For 12V cell battery, if the terminal voltage difference between the cells exceeds 0.4V or the internal resistance exceeds 80m Ω, it is necessary to charge each cell evenly to restore the internal resistance and eliminate the terminal voltage imbalance between the cells. When equalizing charging, the charging voltage is 13.5-13.8v. The internal resistance of most of the batteries after well balanced charging can be restored to less than 30 m Ω. The following is an introduction:

1. Charging by peak power supply

In order to prevent the battery from premature damage due to long-term insufficient charging, it is necessary to make full use of the peak power supply to charge the battery to ensure that the battery has enough charging time after each discharge. Pay attention to the selection of charger during charging. It is better to choose a charger with both constant current and constant voltage to charge the battery.

2. Reduce deep discharge

Its service life is closely related to the depth of discharge. The lighter the load of UPS is, the greater the ratio of available capacity of battery to its rated capacity is when mains power supply is interrupted. In this case, when UPS power supply is automatically shut down due to low battery voltage, the depth of battery discharge is relatively deep. When the UPS power supply is in the state of power supply interruption and battery power supply is changed to inverter, the vast majority of UPS power supply will ring a periodic alarm sound with a gap of about 4S to inform the user that the battery is providing energy. When the alarm sound changes rapidly, it means that the power supply has been in deep discharge. Emergency treatment should be carried out immediately and the UPS power supply should be turned off. Generally, do not let ups work until the battery voltage is too low and automatically shut down.

3. Regular inspection

Regularly check the terminal voltage and internal resistance of each cell battery. For 12V cell battery, if the terminal voltage difference between the cells exceeds 0.4V or the internal resistance exceeds 80m Ω, it is necessary to charge each cell evenly to restore the internal resistance and eliminate the terminal voltage imbalance between the cells. When equalizing charging, the charging voltage is 13.5-13.8v. The internal resistance of most of the batteries after well balanced charging can be restored to less than 30 m Ω.

4. Re floating

UPS power supply is used to make use of the electronic product circuit in the machine to recharge the battery for more than 10-12h and then run with load. UPS power supply is in floating charge state for a long time without discharging process, which is equivalent to being in the state of "storage for use". If this state lasts for a long time, the battery will be invalid and scrapped due to "too long storage". It mainly shows that the internal resistance of the battery increases, and when it is serious, the internal resistance can reach several Ω. Therefore, it is suggested that the user should intentionally unplug the mains power input every few months, so that the UPS power supply can work in the state that the battery supplies energy to the inverter. When the load is about 30% of the rated output, it can be discharged for about 10 minutes.

5. Ensure the normal working environment temperature of power supply

The available capacity of the battery is closely related to the ambient temperature. In general, the performance parameters of the battery are calibrated at room temperature of 20 ℃. When the temperature is lower than 20 ℃, the available capacity of the battery will decrease, but when the temperature is higher than 20 ℃, the available capacity will increase slightly. Of course, in order to prolong the service life of battery pack, we should not only pay attention to the maintenance and use, but also fully consider the load characteristics (resistance, inductance, capacitance) and size when selecting. Do not let the battery run under excessive light load for a long time, so as to avoid battery scrapping due to too small discharge current.

During the operation of UPS power supply, the above-mentioned imbalance caused by the battery characteristics of each unit changes with time can not be eliminated by the internal charging circuit of UPS power supply. Therefore, if the off-line equalizing charging treatment is not taken in time, the imbalance degree will become more and more serious.

Its service life is closely related to the depth of discharge. The lighter the load of UPS is, the greater the ratio of available capacity to rated capacity is when the power supply is interrupted. In this case, when the UPS power supply is automatically shut down due to low battery voltage, the depth of battery discharge is relatively deep.