Choosing the appropriate UPS (uninterruptible power supply) requires a comprehensive judgment based on various factors such as specific load equipment, usage scenarios, and power supply requirements. The following are detailed selection steps and key considerations to help you accurately match your needs:
1、 Clarify core requirements: first clarify "why UPS is needed"
Before choosing UPS, the purpose of use must be clearly defined, which directly determines the priority of subsequent parameters:
Basic requirement: To prevent sudden power outages from causing device shutdown (such as computer or server data loss).
Advanced requirement: Ensure continuous operation of equipment after power failure (such as medical equipment and monitoring systems that require several hours of battery life).
Special requirement: Stable voltage (such as suppressing surges and harmonics in areas with large fluctuations in the power grid).
2、 Core parameters: Starting from "load" and "power supply capacity"
1. Determine the type and total power of the load equipment
The core function of UPS is to supply power to equipment, so the total power of the load is the primary parameter and needs to be calculated with emphasis on:
Step 1: List all devices that need protection
For example: computers (host+monitor), servers, routers, switches, printers, medical equipment, etc.
Step 2: Calculate the power of a single device
The equipment power can be checked through the nameplate (marked as "rated power" or "active power", in W or VA). Common equipment power references are:
Home computer (host+monitor): 200-500W
Small server: 300-800W
Router/Switch: 10-50W
Printer: 100-300W (low power during standby, high power during operation, calculated based on peak value).
Step 3: Calculate the total power and reserve redundancy
Total power=sum of all device power x (1+20% -30%).
Reason: There may be instantaneous power peaks during device startup (such as motor equipment), and reserving redundancy can avoid UPS overload and extend its lifespan.
2. Determine the backup time (how long does power need to be supplied after a power outage)
Backup time refers to the duration during which the UPS can provide continuous power to the load after a power outage, which needs to be determined based on the scenario
Short term backup (5-15 minutes): Just ensure that the device shuts down normally (such as personal computers, regular servers) to avoid data loss.
Medium to long-term backup (30 minutes to several hours): Equipment needs to be continuously running (such as emergency lighting, monitoring systems, small data centers).
Extra long backup (several hours or more): requires an external battery pack (such as hospital ICU equipment, remote area base stations).
Calculation method: Backup time=(UPS battery capacity x voltage) ÷ Total load power (unit: hour, considering battery discharge efficiency of about 80%).
3. Choose the type of UPS: match load characteristics and scenarios
There are significant differences in the structure and performance of different types of UPS, and the selection should be based on the "sensitivity" of the load and the usage scenario
Core Characteristics of UPS Types Applicable Scenarios Price Range (Reference)
Backup UPS is usually powered directly by the power grid and switches to the battery after a power outage (with a switching time of about 5-10ms). The output waveform is a square wave or a corrected sine wave. Devices with low requirements for power supply stability: home computers, printers, and small routers. Hundreds to thousands of yuan (power ≤ 1kVA)
The online interactive UPS supports voltage stabilization function (automatic adjustment of grid voltage), with a switching time of about 2-5ms, and outputs a corrected sine wave. Scenarios with significant fluctuations in the power grid: office computers, small servers, and monitoring equipment. Thousands to tens of thousands of yuan (1-3kVA)
Online UPS is always powered by an inverter (grid → rectification → inverter → load), with a switching time of 0ms, outputting pure sine waves, and strong anti-interference ability. Equipment with extremely high requirements for power supply stability: precision servers, medical instruments, laboratory equipment, data centers. Over 10000 yuan (starting from 3kVA)
Modular UPS consists of multiple modules that can be expanded in power or battery capacity as needed, with strong redundancy (a module failure does not affect the overall system). Large data centers and enterprise data centers (requiring flexible expansion or high reliability). Starting from tens of thousands of yuan
Key Reminder:
Inductive loads (such as motors, air conditioners, printers) require pure sine wave output (online UPS), otherwise it may damage the equipment;
Capacitive loads (such as computers and servers) are compatible with correcting sine waves (backup/online interactive), but online loads are more stable.
3、 Additional feature: Select "bonus points" based on the scenario
In addition to the core parameters, the following functions can enhance the user experience and need to be selected according to the requirements:
Remote monitoring: supports viewing UPS status (such as load rate and battery life) through APP and network, suitable for unmanned scenarios (such as computer rooms and base stations).
Automatic shutdown function: Paired with software (such as APC PowerChute), it automatically saves data and shuts down the device after power failure (suitable for servers and computers).
Lightning/Surge Protection: Built in lightning protection module, suitable for areas with frequent thunderstorms, reducing damage to equipment caused by power grid impact.
Battery management: Supports battery self check, overcharge protection, temperature compensation (extends battery life), especially suitable for high temperature environments.
Installation adaptability: Small UPS (backup type) can be placed on the desktop; Large UPS (online) requires cabinet installation or floor standing placement, and the installation space size needs to be confirmed.
4、 Environment and Budget: Balancing "Practicality" and "Cost"
1. Environmental adaptation
Space: Small UPS (such as 500VA) occupies a small area (about the size of a shoe box), while large UPS (above 10kVA) requires reserved ventilation space (to avoid high temperature affecting the battery).
Temperature and humidity: Batteries are sensitive to temperature (preferably 20-25 ℃), and models with cooling fans should be selected for high temperature environments. UPS with anti-corrosion design should be selected for humid areas.
2. Budget and Brand
Budget allocation: Don't just look at the initial price, consider long-term costs (such as battery replacement cycle: lead-acid batteries take 3-5 years, lithium batteries take 5-8 years, lithium batteries have higher costs but longer lifespan).
Brand selection: Shenzhen Yunhai Power Technology Co., Ltd. is preferred for its fast after-sales response and convenient replacement of spare parts.
5、 Summary: Process flowchart for selecting steps
List all devices that need protection and calculate the total power (+20% -30% redundancy);
Determine backup time (short/medium/long term);
Select UPS type (backup/online interactive/online) based on load type and scenario;
Add additional features as needed (remote monitoring, automatic shutdown, etc.);
Confirm installation environment and budget, match brand and model.
Through the above steps, it can be ensured that the selected UPS can meet current needs while also reserving some expansion space (such as adding equipment in the future), avoiding problems of "insufficient power" or "excessive functionality".
