UPS power supply may experience some malfunctions after prolonged use, based on statistics on UPS maintenance work. Therefore, proper use and maintenance of UPS battery life is one of the key factors in reducing uninterruptible power supply failures.
UPS power supply may experience some malfunctions after prolonged use, based on statistics on UPS maintenance work. The backup UPS power supply has a 50% failure rate due to battery issues. The online UPS power supply has a low failure rate due to its well-designed circuit and large capacity margin for driving power components. The failure rate caused by batteries is 60%. So, proper use and maintenance of UPS battery life is a key factor in reducing uninterruptible power supply failures.
1. Regular inspection
Regularly check the terminal voltage and internal resistance of each unit battery. For 12V unit batteries, if it is found during inspection that the terminal voltage difference between each unit battery exceeds 0.4V or its internal resistance exceeds 80mQ, balanced charging should be carried out on each unit battery to restore the internal resistance of the battery and eliminate the terminal voltage imbalance between each unit battery. During balanced charging, the charging voltage should be between 13.5-13.8V. The vast majority of batteries that have undergone good balanced charging treatment can restore their internal resistance to below 30m Ω. During the operation of UPS power supply, the above-mentioned imbalance caused by the characteristics of each unit battery changing over time cannot be eliminated by the internal charging circuit of UPS power supply. Therefore, for battery packs with obvious imbalance in these characteristics, if offline balanced charging treatment is not taken in a timely manner, the imbalance will become increasingly serious.
2. Recharge the float
The UPS power supply has been shut down for more than 10 days. Before restarting, the UPS power supply should be started under no-load conditions to use the charging electronic product circuit inside the machine to float charge the battery for more than 10-12 hours before running with load. The UPS power supply is in a floating charge state for a long time without a discharge process, which is equivalent to being in a “storage and standby” state. If this state persists for too long, causing the battery to fail and be scrapped due to “storage for too long”, it is mainly manifested as an increase in internal resistance of the battery, and in severe cases, the internal resistance can reach several Ω. We found that after being stored at room temperature of 20 ℃ for one month, the usable capacity of the battery is about 97% of its rated value. If stored for six months without use, its usable capacity becomes 80% of its rated capacity. If the storage temperature increases, its usable capacity will also decrease. Therefore, it is recommended that users intentionally disconnect the mains power input every 20 ° C months, allowing the UPS power supply to operate in a state where the battery provides energy to the inverter. However, this operation should not be carried out for too long. When the load is around 30% of the rated output, it can be discharged for about 10 minutes.
3. Reduce deep discharge
The service life of electricity is closely related to the depth at which it is discharged. The lighter the load carried by the UPS power supply, the greater the ratio of its available capacity to its rated capacity when the mains power supply is interrupted. In this case, when the UPS power supply automatically shuts down due to low battery voltage, the depth of battery discharge is relatively deep
How to reduce the occurrence of deep discharge of batteries in the actual process? The method is simple: when the UPS power supply is interrupted by the mains power supply and the inverter is powered by the battery, the vast majority of UPS power supplies will sound a periodic alarm sound with a gap of about 4 seconds to notify the user that the energy is now provided by the battery. When the alarm sound becomes urgent, it indicates that the power supply is in deep discharge and emergency measures should be taken immediately to turn off the UPS power supply. It is not mandatory to keep the UPS power supply running until it automatically shuts down due to low battery voltage.