The Necessity And Suggestion Of UPS Battery Maintenance

The Necessity And Suggestion Of UPS Battery Maintenance(2)

(2) Turn on the UPS, charge the battery pack, and stabilize the battery pack for more than 1 hour after being fully charged.

Perform a 10-hour rate discharge test on the battery that was found to be the worst when discharging in (1).

The terminal voltage, temperature, discharge time and room temperature of the battery were measured and recorded before and after discharge. Recording is measured every 1 hour.

(3) When the discharge reaches the end voltage, it should be measured and recorded at any time to accurately record the discharge time.

(4) The discharge current multiplied by the discharge time is the battery pack capacity. If the room temperature is not 25°C, it should be converted to the capacity at 25°C according to formula (1).

(5) After the discharge test is completed, charge the battery with a charger to restore its capacity.

(6) Draw a flow curve based on the measured and recorded data.

2.3 Inspection of discharge test method

In order to be able to grasp the approximate capacity of the battery pack at any time, it is necessary to verify the discharge test by the following methods:

(1) In the DC power supply system, adjust the UPS output voltage to the protection voltage, and the battery will supply power according to the actual load. Before and after the battery pack is discharged, measure and record the terminal voltage, temperature, room temperature and discharge time of each battery. Release 30% ~ 40% of rated capacity.

(2) After the discharging is completed, charge the battery, the charging capacity is more than 1.2 times of the discharged capacity.

(3) Draw a discharge curve based on the data recorded by the measurement and save it for comparison when measuring again.

Description:

(1) Offline measurement is not recommended for battery pack capacity test of UPS power supply system.

(2) When performing online measurement methods and verifying capacity tests, for UPS devices with battery discharge test functions, it is necessary to turn on the battery discharge detection function and perform a discharge test on the battery. For UPS that do not have this function, it is necessary to disconnect the AC input power and perform a discharge test.

2.4 Preventive measures

(1) During capacity testing, it is very important to ensure that the system is running. Therefore, when carrying out capacity tests, it is necessary to know in advance whether there is a planned outage of the mains, and the backup generator set should be in good condition.

(2) Before carrying out the battery capacity discharge test, a multimeter, internal resistance meter, and conductivity meter should be used to conduct a preventive test on the battery.

(3) To ensure the accuracy of the capacity test, a professional battery capacity online tester and virtual load should be used for testing.

3. Battery start instant output high current test

In the actual use process, the switching time of the standby UPS from the mains to the inverter is required to be less than 7ms, and it is generally designed to be 4~5ms. When the mains power supply is abnormal, the battery must output the current required by the load within 4 to 5 milliseconds. If there is a failed battery in the battery pack, it can meet the above-mentioned terminal voltage and capacity requirements, but it is not qualified when discharged at a large current. This situation is a hidden danger, and the battery is in an unqualified state. Because the battery's instantaneous high-current output can only be tested when the utility power is turned off, it is risky to test without knowing the battery performance, and such detection is generally not recommended.