Shulou(Shulou.com)05/31 Report--

How to carry out UPS power selection and battery capacity calculation, in view of this problem, this article introduces the corresponding analysis and solution in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

First, determine the power section first.

In short, the first step is to confirm the power of the device we want the UPS to carry, and then we can confirm the power of the UPS. In general, we recommend that the load power account for 30% to 80% of the UPS power. If the load is too large, such as starting at the same time may cause UPS power overload, the load is too small, not only a waste, but also bad for the performance of the battery.

II. The way UPS works

At present, there are three common working methods in the market: backup, online interactive and online double transformation (online pure online). The details are as follows:

(1) backup UPS, without voltage regulator, has conversion time when switching between electricity and battery, and is generally used for personal computer protection, or for use when the performance of UPS power supply is not high. This type of UPS power segment is generally small.

(2) online interactive, without voltage regulation, there is a conversion time when switching between electricity and battery, but it has voltage regulation function, it is generally used in wiring closet or micro-computer room, protection of servers and network equipment, etc., this type of UPS power segment is generally below 5KVA.

(3) online dual-conversion UPS, there is no conversion time between electricity and battery, and no switching time is generally used to protect server or network equipment and other devices in the computer room. This type of UPS power range is available from small to large, with a large span of 1KVA~1000KVA, which is more common in the market.

The performance of the above several UPS power supplies from high to low is in the following order: online double conversion, online interactive, backup. The price is generally proportional to the performance. Do we have to choose the expensive UPS? The answer is no. As our title, we have to choose the UPS that suits us. If it is for a personal computer, then you can choose a backup UPS. If it is for a server, you should choose between online interactive and online double transformation. The selection should be made according to the following conditions:

1. Equipment requirements

To see if your equipment needs high-precision power supply, you can check the logo on the nameplate of the load device or ask the equipment manufacturer. If you need high-precision power supply, you need to choose on-line double-conversion UPS. The second is to look at the load type, some loads do not allow power supply flash, such as: relay equipment or switch signal equipment, if you are equipped with online interactive UPS for this type of equipment, then it is possible that when the UPS city power and battery switch, the load has power outage or misoperation, so for this kind of equipment should choose online double conversion UPS. If your device does not have the above two requirements, you can continue with the following steps.

2. Local power grid

If the quality of the local power grid is relatively good, that is to say, the usual voltage fluctuation is small, you can consider choosing online interactive UPS at this time. However, if the quality of the local power grid is poor and the voltage fluctuates greatly, then we recommend using online double-conversion UPS, because this type of UPS has better adaptability to municipal power than online interaction.

3. Follow-up flight time from UPS to battery

If you require a long time delay, you can consider choosing a dual-purpose machine or buying a UPS without a built-in battery, both of which can be equipped with an original battery or a third-party battery to achieve a longer time delay.

4. Installation mode

Generally speaking, there are two installation modes of UPS power supply, one is tower installation, the other is rack installation, which can be selected according to your computer room environment or site environment, and it should be noted that not all UPS power supplies support these two installation methods at the same time. In most cases, rack UPS can also do tower installation, but tower UPS may not necessarily do rack installation. Because the tower UPS may not be able to install the rails. Therefore, after confirming the UPS power segment and working mode, be sure to confirm whether the UPS power supply can meet your installation requirements.

III. Advantages and disadvantages of different types of UPS batteries

First: the types of batteries commonly used in UPS, the factors that affect battery life, and the advantages and disadvantages of different types of batteries:

There are three types of batteries in UPS applications: open liquid lead-acid battery, maintenance-free battery and nickel-chromium battery. At present, the batteries provided by UPS manufacturers are generally maintenance-free, so the following are mainly about the characteristics of three types of batteries:

1: open liquid lead-acid battery: this kind of battery can be divided into 8-10 years and 15-20 years according to its structure. Because this battery produces corrosive gas by sulfuric acid electrolysis, such batteries must be installed in rooms that are ventilated and away from precision electronic equipment, and the battery room should be paved with anti-corrosion tiles.

Due to evaporation, the specific gravity of the open battery needs to be measured regularly, adding acid and water. This battery can withstand high temperature, high pressure and deep discharge. The battery room should be smoke-free and use an open battery rack.

This battery cannot be transported after charging, so it usually takes 55-90 hours for the battery to be charged after it is installed on site. The normal voltage per section is 2V, and the initial charging voltage is 2.6-2.7v.

2: maintenance-free battery: also known as valve-controlled sealed lead-acid battery, the following principles should be followed in use and maintenance:

A: the allowable operating range of sealed battery is 15-50 degrees, but using within 5-35 degrees can prolong battery life. Below 15 degrees below zero, the chemical composition of the battery will change and cannot be recharged. If you use it in the range of 20 to 25 degrees, you will have a lifetime. The battery will have a long life but low capacity when running at low temperature, and a higher capacity but short life at high temperature.

B: the relationship between battery life and temperature can refer to the following rule: when the temperature exceeds 25 degrees Celsius, the battery life will be halved for every 8.3 degrees Celsius.

C: the design floating charge voltage of maintenance-free battery is 2.3V/ section. The battery of 12V is 13.8V. CSB recommends 2.25V-2.3V per session. In the case of 120 batteries in series, when the temperature is higher than 25 degrees Celsius, the floating charge voltage should be reduced by 3MV for every degree of temperature increase. In order to avoid undercharging voltage, the 3MV should be increased for each degree increase of temperature. The discharge termination voltage is at full load (

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