The maintenance of uninterruptible power supply (UPS) directly affects its stability and service life. The following are detailed maintenance precautions, covering key aspects such as daily inspection, battery maintenance, environmental management, and fault handling:
1、 Daily operation inspection
1. Status monitoring
Panel indicator lights: Check daily whether the UPS panel indicator lights are normal (such as power input, battery status, load percentage, etc.), and be alert to warning lights (such as overload, battery failure, bypass power supply, etc.).
Display screen information: Confirm whether the input voltage, frequency, output voltage, load rate, battery remaining capacity (SOC), backup time, and other data are within the normal range.
Typical normal range: Input voltage fluctuation ≤ ± 10%, output voltage fluctuation ≤ ± 3%, recommended load rate ≤ 80% (avoid long-term full load).
Abnormal sound: Monitor whether the fan is running smoothly and whether there is any abnormal noise (such as friction or whistling), and whether there is any abnormal vibration or noise in the transformer or inductance components.
2. Environmental and Physical Inspection
Temperature and humidity: Ensure that the operating environment temperature of UPS is between 0 ℃ and 40 ℃ (ideally around 25 ℃), and the humidity is ≤ 90% (without condensation). High temperature can accelerate battery aging, while humidity can easily lead to short circuits.
Cleaning and dust removal: Regularly use a dry soft cloth or vacuum cleaner to remove dust from the body (especially from the air inlet and fan), to avoid dust accumulation affecting heat dissipation or causing short circuits.
Tightening connection: Check whether the input/output cables and battery connection wires are loose, and whether the terminals are oxidized or corroded (can be wiped with anhydrous alcohol) to avoid poor contact and malfunction.
2、 Battery pack maintenance (core components)
1. Lead acid batteries (most common)
Regular charging and discharging:
Floating charging state: When the UPS is powered by mains electricity for a long time, the battery is in a floating charging state. It is recommended to conduct an active discharge test every 3-6 months (simulate mains power interruption, let the UPS discharge with load to 30%~50% of the battery capacity, and then recharge) to prevent battery "passivation" (long-term floating charging leads to decreased activity).
Full discharge cycle: At least once a year, deep discharge (discharge until the backup time is less than 50% of the design value), then fully charge to activate the activity of the battery plates.
Appearance inspection:
Check whether the battery casing is bulging, leaking, or deformed, and whether the pole is corroded (the white powder is sulfated and needs to be cleaned or replaced in a timely manner).
Measure the voltage of a single battery (standard voltage: 12V battery is about 12.6V, 2V battery is about 2.25V), and if the voltage deviation exceeds ± 0.3V, check whether it has failed.
Balanced charging: For systems with multiple batteries connected in series, regular balanced charging (UPS built-in function or manually set) is performed to eliminate voltage differences between individual batteries and avoid "short board effects".
Service life: The design life of lead-acid batteries is usually 3-5 years (depending on ambient temperature and charging and discharging frequency). If the discharge time is significantly shortened (such as below 50% of the nominal value), the battery pack needs to be replaced as a whole.
2. Lithium batteries (such as lithium iron phosphate)
Avoid overcharging and overdischarging: rely on the built-in BMS (Battery Management System) protection of UPS, and strictly prohibit manual forced discharge to low voltage.
Temperature management: Lithium batteries are more sensitive to high temperatures, and the ambient temperature should be controlled at around 25 ℃, avoiding direct sunlight or proximity to heat sources.
Regular inspection: Check the battery module indicator lights (such as charging and discharging status, fault lights), and use UPS monitoring software to check whether the voltage and temperature of individual batteries are balanced.
3、 Regular professional maintenance
1. Functional testing
Switching test: Simulate a mains power interruption to test whether the UPS can quickly switch to battery mode (switching time should be less than 10ms, online UPS theory is 0ms), and check the stability of the output voltage.
Overload test: Within a safe range (such as gradually increasing the load rate to 125%), test whether the UPS triggers overload protection or switches to bypass, and whether it can switch back to inverter mode normally after recovery.
Bypass test: Manually switch to bypass mode and check if the bypass power supply voltage and frequency are consistent with the UPS output to avoid abnormal bypass power supply.
2. Performance calibration
Voltage/frequency calibration: Use a high-precision multimeter or oscilloscope to calibrate the accuracy of UPS output voltage and frequency (such as nominal 220V ± 1%, which needs to be verified through actual testing).
Battery capacity testing: Conduct full capacity discharge using a professional load tester, accurately calculate the actual capacity (Ah) of the battery pack, and evaluate the degree of aging by comparing it with the nominal value.
3. Component replacement
Fan replacement: The lifespan of the fan is about 5-7 years. If there is a decrease in speed, abnormal noise, or stoppage, it should be replaced in a timely manner to avoid UPS overheating and shutdown.
Capacitor inspection: Open the chassis (requires professional operation) to check whether the electrolytic capacitor is bulging or leaking. Aging capacitors may cause inverter failure.
4、 Environmental and Safety Management
1. Environmental optimization
Ventilation and heat dissipation: Ensure that there is at least 30cm of heat dissipation space around the UPS, avoid blocking the air inlet/outlet, and install air conditioning or heat dissipation fans if necessary.
Dustproof and moisture-proof: In dusty or humid environments, equip UPS with dust-proof nets (regularly cleaned) or install them in enclosed cabinets (with dehumidifiers).
Lightning protection measures: Install surge protectors (SPDs) at the input end of the mains power supply to prevent lightning strikes or grid surges from damaging the internal components of the UPS.
2. Safe operation
Power off maintenance: When performing internal cleaning or replacing components, be sure to turn off the UPS and disconnect the battery pack to avoid electric shock (there is residual charge in the high-voltage capacitor inside).
Corrosion prevention: The battery pack should be placed on an acid and alkali resistant tray or bracket. If there is a leakage, it should be immediately neutralized and cleaned with sodium bicarbonate solution to prevent corrosion of the floor or rack.
Identification and Recording: Post "High Voltage Danger" signs near UPS and battery packs, establish maintenance records (recording information such as inspection time, parameters, and replacement parts) for easy traceability of issues.
Through scientific and standardized maintenance, the reliability of UPS can be significantly improved, equipment lifespan can be extended, and the continuous and stable operation of critical loads such as servers, medical equipment, and industrial control systems can be guaranteed.
