The PROLINK PRO1201 1200VA Super-Fast Charging UPS AVR is designed to provide reliable backup power and voltage protection for computers, networking equipment, and home electronics. It helps keep connected devices running during short power interruptions. The UPS provides a 1200VA capacity and uses Automatic Voltage Regulation (AVR) technology. Additionally, it helps stabilize unstable voltage levels to protect connected equipment from power fluctuations. The PROLINK PRO1201 features super-fast charging technology that helps reduce battery recharge time. Moreover, it allows the UPS to recover power faster after an outage and prepares it for future use. The UPS includes multiple protection features to help protect connected devices. Furthermore, it provides protection against overload, short circuit, surge, and low battery conditions during operation. The PROLINK PRO1201 features LED indicators that display important operating status information. Therefore, users can easily check the UPS condition and power status. The compact design makes the UPS suitable for homes, offices, and small workspaces. In addition, it provides a practical backup solution for computers, routers, and other essential devices. The PROLINK PRO1201 1200VA Super-Fast Charging UPS AVR combines backup power, voltage regulation, fast charging, and safety features. As a result, it provides reliable power support for everyday electronic equipment. Specifications: Capacity: 1200VA / 720W Technology: Automatic Voltage Regulation (AVR) Charging: Super-Fast Charging Technology Protection: Overload, Short Circuit, Surge, Low Battery Protection Display: LED Status Indicators
Features • Advanced DSP and 3-level technology • Output power factor 1.0 • Active power factor correction (APFC), input power factor up to 0.99 • High efficiency 95% (up to 98% in ECO mode) • Advanced digital parallel technology • Wide input voltage range (11 0 – 288 Vac) and frequency range (40 -70Hz) • 50 I 60 Hz frequency auto sensing • Two modes of frequency conversion: 50 Hz input I 60 Hz output or 60 Hz input I 50 Hz output • Dual-input design, supporting independent bypass • Flexible battery configuration (settable 16-20 pes batteries) • Digitally controlled charger • High charging current available (Max. 12 A) • Charging voltage and current configured by demands • Linear derating in low voltage input reducing battery discharging times, extending the service life of battery • Intelligent battery management, automatic floating I equalizing charge control, charger dormancy control, increasing battery life by 50% • Ability to switch on the UPS with batteries • Settable delayed start time when mains power is restored, reducing the impact on power grid or generator • Fan speed varies intelligently with temperature, reducing noise and extending its service life • Equipped with self-aging function • Compact internal layout, miniaturized the complete unit for small footprint • LCD+LED display, multi-functional keys operation, friendly human-machine interface • Powerful background software for parameters configuration • Advanced multi-platform communications: RS232, USB, RS485, SNMP and dry contacts communication interfaces • Effective software and hardware protection function, robust self-diagnostic function, and abundant event log for check Available Options • RS232 and smart card slot included • Optional parallel function, battery temperature compensation, SNMP card, USB, RS485 card, dry contacts, EMD, and SMS alarms Specifications Voltage range OUTPUT Output wiring Rated voltage Voltage regulation Frequency Waveform Power factor Total harmonic distortion (THDv) Crest factor Overload BATTERIES DC voltage Number of battery lnbuilt battery (standard model) Charging current Recharge time EM Efficiency Transfer time Protections Max. number of parallel connections Communications Display OTHERS Operating temperature Storage temperature Relative humidity Altitude !Prating Noise level at 1 m Dimensions (W x D x H) (mm) Packaged dimensions (W x D x H) (mm) Net weight (kg) Gross weight (kg) 110- 176 Vac (linear derating between 50% and 100% load); 176- 288 Vac (no derating) Single-phase three-wire (1 Cll + N + PE) 208 (PF=0.9) 1220 1230 1240 Vac ± 1% Synchronized to bypass in mains mode; 50 160 Hz±0.1% Hz in battery mode Sinusoidal 1 s 1% (linear load); s 4% (non-linear load) 3:1 105%- 110% for 10 min, 110%- 125% for 1 min, 126%- 150% for 30 s 192 Vdc (192- 240 Vdc settable) 16 pes (16- 20 settable) 12VI7Ahx16 I 12VI9Ahx16 Standard model: 1 A; Long time model: 5A(default), 1 – 5Asettable, 12A (optional) Standard model: 90% capacity restored in 8 hours; Long time model: depend on the capacity of battery ~ 94% at 100% load, max. 95% at 60% load,~ 98% in ECO mode Oms Short-circuit, overload, overtemperature, battery low voltage, overvoltage, undervoltage and fan failure 4 RS232 (standard), USB I RS4851 dry contacts I SNMP I baltery temperature compensation (optional) LCD+ LED O”C – 40″C -25″C – 55″C (without battery) 0 – 95% (non-condensing) s 1 000 m, derating 1% for each additional 1 00 m IP20 S55dB S58dB 191 X 465 X 711 (S), 191 X 465 X 350 (H) 191 X 495 X 711 (S), 191 X 495 X 350 (H) 310 X 654 X 941 (S), 318 X 595 X 475 (H) 310 X 685 X 941 (S), 318 X 617 X 475 (H) 53 (S), 14.5 (H) 62 (S), 16.5 (H) 61 (S), 16 (H) 70 (S), 18 (H)
Specifications : GENERAL UPS Type : Tower Phase : Single phase with ground Rating (VA) : 2000 Nominal Power (W) : 1600 Standard Model Dimension (mm) : 397x 145 x 220 (D x W x H) Weight (kg) : 17 Long-run Model Dimension (mm) : 397 x 145 x 220 (D x W x H) Weight (kg) : 6.8 INPUT Connection Type : IEC 320-C14 Nominal Voltage : 200/208/220/230/240 VAC Voltage Range : 110-300 VAC (Load at 50%) 160-280 VAC (Load at 100%) Frequency Range : 45 ~ 70 Hz Power Factor : >= 0.99 OUTPUT Connection Type : 3 x Universal socket (PRO902WS) 2 x Universal socket (PRO902WL) Nominal Voltage : 200/208/220/230/240 VAC Voltage Regulation : ±1% Frequency Range (Synchronized Range) : 47 ~ 53 Hz or 57 ~ 63 Hz Frequency Range (Batt. Mode) : 50 Hz ± 0.25 Hz or 60 Hz ± 0.3 Hz Current Crest Ratio : 3:1 Harmonic Distortion ; ≤3% THD (Linear load) ≤6% THD (Non-linear load) ALARM & INDICATORS Battery Mode : Sounding every 4 seconds Low Battery : Sounding every second Overload : Sounding twice every second Fault : Continuously sounding LCD : Load level, Battery Level, AC mode, Battery mode, Bypass mode and Fault CONNECTIVITY, CONTROL & MONITORING Front panel : Status LED, Function keys, LCD display Communication : Smart RS232* USB : Port BATTERY Standard Model Type : 12V / 9Ah Numbers : 4 Typical Recharge Time : 4 hours recover to 90% capacity Long-run Model Type : Depending on the capacity of external batteries Number : 4/6/8 Charging Current (max) : 1A / 2A / 4A / 6A Adjustable REAR PANEL 1. AC Input 2. Input circuit breaker 3. USB Communication port 4. RS-232 communication port 5. Intelligent slot 6. External battery connection (Only available for L model) 7. Output receptacles
APC Easy UPS On-Line SRV 3000VA 230V SRV3KI is a high-performance uninterruptible power supply designed to provide continuous power protection for servers, network equipment, data centers, and critical business systems. It uses true online double-conversion technology to deliver clean and stable power in demanding environments. The UPS provides 3000VA / 2400W power capacity. Therefore, it can support critical equipment during power outages, voltage fluctuations, and electrical disturbances. In addition, it helps maintain business continuity and equipment reliability. It features online double-conversion technology that continuously conditions incoming power. As a result, connected devices receive consistent and clean power regardless of utility power quality. The unit includes an LCD display for real-time monitoring and system management. Meanwhile, automatic bypass functionality helps maintain power delivery during specific operating conditions and maintenance events. APC designs the Easy UPS On-Line series for dependable power protection and efficient operation. Therefore, this model is ideal for servers, network infrastructure, security systems, and mission-critical applications. manufacturer link Specifications: 3000VA / 2400W power capacity Online double-conversion technology Pure sine wave output LCD status and monitoring display Reliable backup for critical systems
Specifications : Le grand ups keor spx 2kva 2000va 1200w ups 2kva 1 year warranty
Original product name: UPS 5E1100iUSB Eaton Line Interactive UPS 1100VA / 660W, AVR, 6 IEC, USB port, software, Input / Output jacks included for Telephone / Modem / Internet Line surge protection | 2 Years Warranty 5E1100iUSB Eaton Line Interactive UPS 1100VA / 660W, AVR, 6 IEC, USB port, software, Input / Output jacks included for Telephone / Modem / Internet Line surge protection, 2 Years Warranty (Including Battery)
LiFePO4 BATTERY SYSTEM LPBF Series 48250-48300 48V 250ah Solar Panel Rechargeable Lithium Battery For Energy Storage System model LPBF48250 capacity 48V 12.5KWH Voltage 48V Rated Voltage 51.2V Charge Voltage 57.6V Discharge Voltage Range 48-57.6V MAX.Charge&Discharge Current 120A DOD 95% Modeles Connection 1-6 in parallel Ingress protection IP21 Cycle Life >6000, @25°C Working Temperature Range -10-50°C Net Weight(kg) 159KG Gross Weight(kg) 183KG Dimension(MM) 615*350*955MM 5 Years Warranty Specifications: LiFePO4 BATTERY SYSTEM LPBF Series 48250-48300 model LPBF48250 capacity 48V 12.5KWH Voltage 48V Rated Voltage 51.2V Charge Voltage 57.6V Discharge Voltage Range 48-57.6V 5 Years Warranty
INVO Online INH300 Centralized server center, mainframe, network control center, computing center Full Specifications : 3KVA 2100 W Half -Load 120 -300VAC, Full -Load 165V -300VAC 45.5Hz ~ 54.5Hz 220/230/240V ± 3% Waveform True Sine wave Frequency 50/60Hz ± 0.5 Distortion <3%(linear Load); <5%(Non -linear Load) Crest Factor 3:1 Efficiency 85% Overload Capacity 110%-150%:Switch to Bypass after 1min; >150%:Shutdown afte r 200ms Short Circuit UPS output turn off and alarm RS232 ;SNMP (Optional) LCD & LED Utility, Inverter, Bypass, Battery, Load ,Battery Mode ,Frequency , UPS Fault Indicator Audible Alarm -Battery Discharge Utility Failure, Beep/4s;Battery Low, Beep/1s UPS Abnornmal Continuous Beep and Red Led On Noise <55db (1Meter) Temperature 0°C~40°C Humidity 10%~90% Optional 19 inch Rack -mount Dimension (W * D * H) mm 357 x 144 x 215 439x190x341 514X262X455 (Long Time Mode) 514x262x710 (Standard Model) Specifications: Specifications : INVO Online UPS High Frequency 3000 VA, LCD Display Inbuilt Battery 6 x 12V/7Ah AC Input 2. Bypass 3. AC Output 4. Battery 5. Fault 6. Screen 9. LCD 1. AC Input 2. Bypass 3. AC Output 4. Battery 5. Fault 6. Screen 9. LCD 1 year warranty Manufacturer Link
APC UPS Accessories SRVRK1 APC Easy UPS RAIL KIT, 700MM, 1 – 10KVA (Rackable SRV models)
APC UPS Accessories APV9601 EASY UPS ON-LINE SNMP CARD, 1 – 10KVA (SRV models)
The PROLINK IPS5003 Inverter is designed to provide reliable backup power for homes, offices, and essential electronic devices. It helps users maintain power during outages and supports stable operation for different electrical equipment. The inverter provides a 5000VA capacity and delivers stable AC power output for compatible devices. Additionally, it supports backup power needs for appliances, computers, and other important electronics. The PROLINK IPS5003 features pure sine wave output to provide clean power for sensitive equipment. Moreover, this technology helps improve compatibility with devices that require stable electricity performance. The inverter includes an LCD display that allows users to monitor important system information. Furthermore, users can check battery status, input voltage, output voltage, and operating conditions easily. The PROLINK IPS5003 includes protection features against overload, short circuit, over-temperature, and low battery conditions. Therefore, it helps protect connected devices and improves system safety during operation. The inverter supports different backup power applications for homes and small offices. In addition, its practical design makes it suitable for users who need dependable energy support during power interruptions. The PROLINK IPS5003 Inverter combines high power capacity, pure sine wave technology, monitoring features, and protection functions. As a result, it provides a reliable backup power solution for everyday electrical needs. manufacturer link Specifications: Capacity: 5000VA Output Waveform: Pure Sine Wave Display: LCD Display Protection: Overload, Short Circuit, Over Temperature, Low Battery Protection Application: Backup Power for Home and Office Equipment
Specifications : Le grand ups keor spx 800va 310301 1year warranty ups 800va
General Topology Online double conversion Configuration Tower Part Number 9E1000I Rating (VA/Watts) 1000/800 Dimensions (H x W x D, mm) 356 x 228 x 144 Weight (kg) 9.5 Electrical Input Connection (1) IEC-320-C14 Input Voltage Range 176-300V without derating (up to 100-300V with derating) Nominal Voltage 208/220/230/240V Frequency 50/60 Hz autoselection Frequency Range 40-70 Hz Electrical Output Voltages 208V*/220V/230V/240V ±1% Voltage THD <2% for 100% linear load Outlets (4) IEC-320-C13 Overload Capacity 105%-130% : 60s, 130%-150% : 10s,>150% : ≥ 300ms Efficiency (Normal Mode) Up to 91% in Online mode Output Frequency 50/60 Hz autoselect Communications Communication Ports 1 USB port + 1 RS232 serial port (USB and RS232 ports cannot be used simultaneously) Communication Slot 1 slot for Network-M2, ModBus-MS or Relay-MS cards Power Management Software Intelligent Power Editions Environmental & Standards Audible Noise <37 dB @ typical load Operating Temperature 0 to 40°C Safety markings IEC/EN 62040-1 EMC Markings IEC/EN 62040 -2 Approvals CE, CB report (TUV) 2 Years Warranty manufacturer link
The Beco GP1200 1200VA 720W UPS delivers reliable power backup for home and office electronics. It keeps key devices running during outages. This helps prevent data loss and sudden shutdowns. Users gain peace of mind knowing devices stay protected. Moreover, the Beco GP1200 1200VA 720W UPS features 1200 VA capacity and 720 W output power for strong support. It handles computers, routers, modems, and monitors easily. Large systems stay powered long enough to save work. Performance stays stable and secure. In addition, the UPS includes built-in surge protection for reliable defense against voltage spikes. It guards appliances from unstable power conditions and electrical surges. This adds extra safety during storms or fluctuations. Protection stays consistent over time. Furthermore, the Beco GP1200 1200VA 720W UPS offers automatic voltage regulation without manual settings. It smooths voltage drops and spikes quickly. This helps connected devices run smoothly. Reliability increases in daily use. Also, the UPS provides battery backup when power fails. You can finish tasks and save important files before turning off systems. This reduces the risk of data corruption. Backup power feels dependable. In addition, the Beco GP1200 1200VA 720W UPS includes clear LED indicators for power and battery status. You can check performance at a glance. This helps monitor conditions with ease. Users stay informed during operation. Moreover, the UPS includes multiple output sockets for connecting more devices at once. This improves flexibility for busy workstations and entertainment setups. You can protect multiple electronics with one unit. Furthermore, the Beco GP1200 1200VA 720W UPS supports easy installation and quick setup. Users can connect devices without complicated steps. Setup remains simple for all users. Also, the compact design fits neatly on desks, shelves, or cabinets without taking much room. It blends well into home and office spaces. Portability stays practical. Overall, the Beco GP1200 1200VA 720W UPS delivers strong battery backup, surge protection, and smooth voltage regulation. It guards electronics and ensures uninterrupted use. This UPS is ideal for users seeking reliable, everyday power protection. Specifications: 1200VA, 720W, LED, Plastic Case Input: 140-290 VAC Output: 230VAC 50/60HZ 12V 7.5AH *2pcs, Universal Socket *4 + EU Plug With AVR, Bypass output Overload and short circuit protection
INVO online INH1000 NVO Online UPS High Frequency 10000 VA, LCD Display Inbuilt Battery 16 x 12V/9 Ah Specifications: Specifications : AC Input Bypass AC Output Battery Fault Screen LCD AC Input Bypass AC Output Battery Fault Screen LCD 1 year warranty Manufacturer Link
9E20Ki Eaton Online Double Conversion 9E 20KVA / 16000W Combo: 1:1 and 3:1, In-Built Automatic Relay Bypass, Intelligent Power Software, 1 USB port + 1 RS232 serial port (USB and RS232 ports cannot be used simultaneously), 1 slot for Network-MS, ModBus-MS or Relay-MS cards, 1 Year Warranty
The PCE Battery 12V 9Ah is a reliable and efficient power solution for various applications. Whether you need backup power for a UPS system or energy for your equipment, this battery ensures consistent performance. With a 12V output and 9Ah capacity, the PCE Battery delivers the power you need to keep your devices running smoothly. It’s ideal for use in security systems, emergency lighting, and other critical equipment. Designed for durability, the PCE Battery offers a long lifespan and requires minimal maintenance. Its sealed, lead-acid design ensures that it remains leak-proof and safe for use in different environments. The PCE Battery 12V 9Ah is compatible with a wide range of devices and systems. Whether you’re using it for home backup, industrial equipment, or a solar energy system, it provides dependable power when needed. This battery features advanced technology for efficient energy storage and reliable discharge. It also includes built-in safety features like overcharge and short-circuit protection, ensuring safe and stable operation. One of the key benefits of the PCE Battery is its easy installation. Whether you’re an expert or a beginner, this battery can be quickly installed and connected to your system with minimal effort. In conclusion, the PCE Battery 12V 9Ah is a perfect combination of reliability, performance, and safety. Choose this battery for a stable power supply and enjoy long-lasting energy for all your essential devices. Specifications: Voltage : 12V Capacity : 9Ah
Specifications : GENERAL Rated Power 5000VA / 5000W Communication Interface Removable USB / RS232 / RS485 / Bluetooth / Dry-contact Dimension D x W x H (mm) 115 x 300 x 400 Net Weight (kgs) 13 INPUT Voltage 230VAC Selectable Voltage Range 170 ~ 280 VAC (For Personal Computers)90 ~ 280 VAC (For Home Appliances) Frequency Range 50Hz / 60Hz (Auto sensing) OUTPUT AC Voltage Regulation (Batt. Mode) 230VAC ± 5% Surge Power 10000VA Efficiency (Peak) 90% ~ 93% Transfer Time 15 ms (For Personal Computers)20 ms (For Home Appliances) Waveform Pure sine wave BATTERY Battery Voltage 48VDC Floating Charge Voltage 54VDC Overcharge Protection 63VDC SOLAR & AC CHARGER Solar Charger Type MPPT Maximum PV Array Open Circuit Voltage 500VDC Maximum PV Array Power 5000W MPP Range @ Operating Voltage 120VDC~450VDC Maxmum Solar Charge Current 100A Maximum AC Charge Current 100A manufacturer link
Prolink PRO3000SFCU 3000VA is a line-interactive UPS designed to provide stable backup power for PCs, servers, networking devices, and sensitive electronics. It ensures continuous operation during power cuts and voltage fluctuations. In addition, Prolink PRO3000SFCU 3000VA supports a wide input voltage range of 140–300VAC. Therefore, it stabilizes unstable electricity using automatic voltage regulation (AVR). Moreover, it delivers a fast transfer time of around 2ms for seamless switching between mains and battery mode. Furthermore, Prolink PRO3000SFCU 3000VA includes four 12V/10Ah batteries for extended backup support. As a result, it provides reliable runtime for critical systems depending on load. It also supports simulated sine wave output for compatible devices. In addition, Prolink PRO3000SFCU 3000VA features intelligent microprocessor control. Therefore, it improves efficiency, protection, and battery management. Moreover, it includes indicators and alarms for battery, overload, and fault conditions. Overall, Prolink PRO3000SFCU 3000VA delivers strong backup performance, stable voltage regulation, and reliable protection for home and office power needs. Specifications: 3000VA capacity for PCs and office equipment Line-interactive UPS with AVR voltage regulation Wide input range 140–300VAC for unstable power Fast ~2ms transfer time for uninterrupted switching Four 12V/10Ah batteries for extended backup support
The Prolink Online UPS 10KVA with LCD and Internal Battery is designed to provide stable power protection for servers, networking equipment, and critical electronic systems. It helps maintain continuous operation during power failures and protects devices from unstable power conditions. The UPS provides a 10KVA capacity and uses online double conversion technology. Additionally, it delivers clean and stable power output to support sensitive equipment that requires reliable energy performance. The Prolink Online UPS features an LCD display that allows users to monitor important system information. Moreover, the screen shows details such as input voltage, output voltage, battery status, load level, and operating conditions for easier management. The UPS includes an internal battery system that provides backup power during outages. Furthermore, it supports protection features against overload, short circuit, over-temperature, and battery problems to help protect connected devices. The Prolink Online UPS is suitable for offices, data centers, and professional environments that need continuous power support. Therefore, it provides a practical backup solution for important equipment that requires stable electricity. The UPS combines high capacity, online power protection, battery backup, and monitoring features in one system. As a result, it helps users maintain reliable power performance during unexpected interruptions. Specifications: Capacity: 10KVA UPS Type: Online Double Conversion Display: LCD Display Battery: Internal Battery System Protection: Overload, Short Circuit, Over Temperature Protection
APC UPS Accessories SURTRK APC Smart-UPS RT 19″ Rail Kit 1 – 2.2KVA
Eaton 5S UPS, 1500 VA, 900 W, Input: C14, Outputs: (4) C13, (4) C13 surge only, Tower General Topology Line-Interactive (AVR with Booster + Fader) Configuration Tower or under monitor Part Number 5S1500i Color Black Rating (VA/Watts) 1500/900 Dimensions (H x W x D, mm) 250 x 87 x 382 Weight (kg) 11.08 Electrical Input Connection (1) IEC-320-C14 Input Voltage Range 175V-275 V Nominal Voltage 230 V Operating Frequency 50-60 Hz autoselect Electrical Output Nominal Voltage 230 VAC Output voltage regulation 230 V +/- 10% Outlets (4) IEC-320-C13 (4) IEC-320-C13 surge only Communications Communication Ports HID-compliant USB port for automatic integration with most common operating systems (Windows Vista, 7 & 8, Linux, Mac OS X), cable supplied Environmental & Standards Audible Noise < 40 dB at 1 Meter Operating Temperature 0 to 40°C Safety markings IEC/EN 62040-1, IEC/EN 62040 -5 Markings CB Report, CE mark Data Line Protection Tel/Fax/Modem/Internet and Ethernet 2 Years Warranty manufacturer link
The PROLINK PRO1501SFCU Super Fast Charging UPS is designed to provide reliable backup power and voltage protection for computers, networking equipment, gaming systems, and office electronics. It helps keep essential devices operating during power interruptions and unstable electrical conditions. The UPS provides a 1500VA capacity and uses line interactive technology with Automatic Voltage Regulation (AVR). Additionally, AVR helps stabilize input voltage fluctuations and delivers safer power to connected devices. The PROLINK PRO1501SFCU features super-fast charging technology that significantly reduces battery recharge time after a power outage. Moreover, this feature ensures the UPS becomes ready for the next interruption more quickly. The UPS includes multiple protection functions against overload, short circuit, surge, and battery discharge conditions. Furthermore, these protection features help improve the safety and reliability of connected equipment. The PROLINK PRO1501SFCU includes LED status indicators and audible alarms for easier system monitoring. Therefore, users can quickly check operating conditions and power status during daily use. The compact design makes the UPS suitable for homes, offices, and small business environments. In addition, it provides dependable backup support for desktop PCs, routers, NAS devices, and CCTV systems. The PROLINK PRO1501SFCU Super Fast Charging UPS combines backup power, rapid battery charging, AVR technology, and advanced protection features. As a result, it provides a practical and reliable power protection solution for everyday applications. Specifications: Capacity : 1500VA Input : 140-230VAC Output : 230VAC Transfer Time : 2ms Battery Type : 12V Backup Time : 40 Min (Depending on the load) Part Number : PRO1501SFCU
The APC 1600VA BX1600MI 900W UPS provides reliable backup power for home and office electronics. First, it delivers line-interactive output to protect devices from voltage fluctuations. In addition, it safeguards connected equipment from surges, spikes, and short outages. Moreover, the compact design allows easy placement near computers or servers. Finally, the LCD indicators display battery and load status for real-time monitoring. The BX1600MI-GR ensures uninterrupted operation and reliable protection for critical devices. manufacturer link Specifications: 900W / 1600VA line-interactive output for reliable device protection Protects electronics from power surges, spikes, and outages Compact design for easy placement near computers or servers LCD indicators for monitoring battery and load status Ensures uninterrupted operation during power interruptions