UPS battery configuration calculation method
UPS battery configuration calculation method
Foreword: I haven’t figured out the calculation method of the battery configuration of the UPS.
First, you need to list all the devices that need to be protected. The voltage and current data of each device can be found on the back panel, and the VA value can be obtained by multiplying the two. Some devices use watts to indicate the power needs, and multiply the wattage by a factor of 1.4 to get an approximate VA value. For the power of the overall device, it is based on its rated number. Summarize the VA values of all devices, add the summed value to the total value. 30% expansion capacity for system upgrade.
In addition, the battery power supply time is mainly affected by factors such as load size, battery capacity, ambient temperature, battery discharge cut-off voltage, etc. According to the delay requirements, determine the required battery capacity, which is expressed by the ampere-hour AH value, with a given current ampere Calculate the number of hours of discharge time.
Precautions:
Because the output power factor of the UPS voltage is generally 0.7 (for example, the most supported load power of the Santak C1KS is: 1000VA*0.7=700W, and so on), the choice of the UPS head in the actual environment cannot make the UPS load too large, and the UPS power supply is the most A good load power is about 70-80% of its standard load, so that the service life of the UPS can be better extended.
The general UPS battery configuration formula is as follows:
UPS power (VA) * delay time (hours) / UPS power start DC = required battery ampere hours (AH)
Take the 4-hour delay of the Santak C3KS as an example: (The starting DC of the Santak C3KS is: 96V)
3000 VA*4 hours/96V=125AH
The result is that a 125AH battery is needed to meet the 4-hour power supply, but there is no ordinary battery with a capacity of 125AH in a group of 8 {because the starting DC of the C3KS is 96V (the standard DC voltage of the UPS when it leaves the factory), and the general battery is 12V DC, [ 96V/12V=8], so 8 batteries are a group.
We can choose 100AH battery to configure it; its delay time is: [100AH (battery capacity) * 96V (UPS starting DC voltage) / 3000VA (UPS power supply) = 3.2 hours
You can also choose 2 groups (16) of 65AH batteries in parallel configuration, the extension time is: (65AH2)96V/3000VA=4.16 hours
Santa
The online Castle series UPS power supply is the uninterruptible power supply product with the largest market share in the domestic market. Because of its good product stability and low price, it is very popular among users. Many users do not know how to equip the battery pack when purchasing Castle series UPS power supply. Here is a detailed calculation method in the industry for your reference.
learn
Take C3K as an example here, which is a UPS power supply with a power of 3KVA battery and an inverter voltage of 96V. These information are generally obtained from the company’s website or product information, and the battery pack voltage of different models of machines is different.
calculate
UPS power X 0.7 = actual output power,
3KVA X 0.7 = 2.1KW (actual output power), 2.1KW = 2100 W.
Calculate the total capacity of the battery pack
(actual output power / battery voltage) X delay time = total battery capacity (AH)
Of course, the customer knows the delay time best, for example, it needs to be delayed for 8 hours;
(2100W/96V) X 8H = 175AH (total battery capacity)
Battery selection
Here is only a reference to conventional batteries. The specifications of conventional 12V batteries are: 12V4AH, 12V7AH, 12V17AH, 12A24AH, 12V38AH, 12V65AH, 12V100AH. There is a problem here that needs to be explained. The capacity of batteries connected in series is equal to the capacity of one battery, but the voltage raised. For example: 12V24AH X 8 = 96V 24AH (series battery pack capacity)
According to the third calculation result, the total capacity of the battery is 96V 175AH. We compare the battery specifications and models. To achieve 175AH, two sets of 100AH batteries are required.
175AH / 100AH = 1.75 sets (take 2 sets of 100AH batteries)
There is another problem that needs to be explained here. The actual capacity of the battery is only 70%-90% of the nominal capacity, and the quality of the battery is only 60%.
2 groups of 100AH in parallel = 96V200AH,
96V200AH X 0.85 (average value) = 96V170AH (close to the calculation result of 175AH)
The battery model is determined to be 12V100AH.
Calculate the number of batteries per group
Battery pack voltage / each cell voltage = the number of cells per pack
96V / 12V = 8
Number of battery packs X number of batteries per pack = total number of batteries
2 sets X 8 (each set) = 16 100AH batteries (the number and capacity of batteries required)
Some people here will definitely ask the 2 groups of 100AH battery capacity is only 96V170AH and less than the requirements of 96V175AH, why choose 2 groups of 100AH? Because the UPS is rarely used at full load in the actual application process, and the general load is only 30%-70% of the total output power, the capacity of the UPS battery can generally be slightly smaller than the calculated value.
Of course, the capacity of the battery pack is gradually decreasing every year due to various reasons. Therefore, when the battery pack is equipped, it is up to the customer to decide whether to increase the capacity of the battery pack according to the calculation results and prolong the delay time normally required by the battery pack. time.