The lead acid battery is a kind of energy storage device that stores electrical power in chemical form and converts it back to electricity when needed. It can be used as an alternative source of electric current or stored temporarily until the need arises. Lithium-ion batteries are another type of effective and attractive energy storage solution for telecom applications.
Battery enclosure is to protect batteries from damage and prevent them from being damaged by external factors such as impact or vibration. It also prevents leakage of electrolyte in case of overcharge or short circuit. In addition, it has control and monitoring battery function and can be used to store spare parts and tools.
The design of the battery enclosure is very important to ensure that it last in a long time and has good performance. The design of the battery enclosure is based on a series of requirements and technical conditions. It can be divided into two parts: One is to ensure that the battery has enough space to expand, another part is to prevent water from entering the battery through the ventilation holes in order to avoid short circuit caused by corrosion or electrolysis. In addition, it should also have good heat dissipation performance so as not to affect the normal operation of the battery. there are two types of battery enclosures: one type has a fixed size; another type with adjustable volume.
In this article we will discuss some tips on how to design the best battery enclosure.
How to Determine the Battery Backup Capacity in the Battery Enclosure
The outdoor battery enclosure usually does not supply power, just be used as an emergency power source when the city power is disconnected. Before we know the battery capacity, there are 2 factors have to be calculated:
- The total power load per hour of the telecom active equipment in the enclosure
Most of the internal transmission equipment is powered by 48VDC, based on their electrical parameters like voltage, current, etc. we should know the total power load.
- Battery backup time needs to be defined by project requirement.
Some enclosures are installed in urban area, the battery back up time may be 90minutes even longer. Some battery cabinets are installed in the city, transportation is convenient and the battery back up time is 30minutes.
The total battery capacity is calculated as:
Battery Capacity (in Ah) needed= Total Load (In Watts)* Backup Time (in hours)*Efficiency %(n)/ Input Voltage (V)
How to Determine the Size of the Battery Enclosure? What Kind of Structure Should It Adopt?
Battery enclosure size is based on the application requirements, and the batteries type is chosen. For example, if your battery enclosure needs more power than normal, then you need to increase battery quantities or use larger-capacity batteries.
The common-used batteries for the battery enclosure:
Based on the total power load required, select right type of batteries and battery quantities.
For example:
Quantity of 190AH 12V VRLA batteries = Watt (batteries capacity needed) AH/190AH*4
Quantity of 100AH 48V LiFePO4 battery = Watt (batteries capacity needed) AH/100AH
Battery enclosure dimension can be calculated based on the battery type and quantity, take 16units of 190AH Lead Acid battery as example)
Battery Enclosure Height
The space required for each 190AH battery is 8U, and every four batteries are a string. The required height of the battery = quantity of batteries/4*8U.
On top of the battery enclosure and at the bottom of the battery cabinet, should have 1U each space, which is used to have air circulation
Battery management system (BMS) space requires 3U.
With 16units batteries as 4strings, the height of the battery cabinet should be 37U (4*8U+1U+1U+3U), each U size is 1.75″, the cabinet height is 64.75″.
Battery Enclosure Width: The battery is installed on a 23inch rack, and both VRLA batteries and lithium batteries can be installed. Then there are 4Inch cable installation spaces on enclosure left and right sides to install glands of different specifications. The minimum width dimension of the battery cabinet is 31” (23” + 4” + 4”)
Battery Enclosure Depth: The depth of the 190AH VRLA battery is about 22”. The cold air flow space and cable installation space are 4 inches in the front of the cabinet and 3 inches in the back. The minimum depth of the battery cabinet is 29” (22” + 4” +3”)
The minimum dimensions of the battery enclosure are determined based on the battery type and it’s quantity, it could be adjusted according to other application requirement.
How to Determine the Cooling Solution of the Battery Enclosure?
The battery enclosure is placed outdoors, exposed to the sun, snow and freezing, and the climate is alternately hot and cold, which will cause great damage to the internal batteries. In order to extend batteries life, a suitable climate solution must be designed for the battery enclosure.
There are some commonly used climate solutions: forced ventilation by fans, heat transfer by heat exchangers, direct cooling by air conditioners, heating. Each solution has its own advantages and disadvantages and are applicable to different regions.
Which climate solution to choose depends on the environment and conditions of the battery enclosure. In areas where the climate is mild and the environment is clean and less dusty, forced fan ventilation is applied, and the operating cost of the enclosure is the lowest. In areas with hotter climates and complex environments, heat exchangers are a better choice, and the outdoor enclosures are not susceptible to wind and dust. In hot climate areas, it is necessary to use air conditioners for forced cooling to ensure that the internal temperature of the outdoor enclosure runs in an appropriate range. Relatively speaking, the operating cost is relatively high.
While in winter, some area the temperature is very low, should consider to have heater to warm up the battery enclosure to prevent the battery temperature from being too low and reducing the running efficiency. This is suitable for severe cold areas in the north, where the temperature is below -10℃, but not in warm areas in the south.
How to Determine the Power Management Solution of the Battery Enclosure? How Important of the BMS System?
The batteries are placed in the battery enclosure to provide power to the equipment, and it is also necessary to charge the battery to save enough power. As a part of the overall circuit, the battery needs to be equipped with corresponding circuit breakers, fuse protectors and connecting cables to ensure that the battery can work normally. The selection of these circuit breakers, protectors and cable specifications must match the current intensity of the corresponding battery charging and discharging. In addition, the internal temperature changes, voltage changes, and power changes of the battery during operation need to be detected in time, and a BMS battery management system needs to be equipped to prevent excessive discharge, full, or excessive internal temperature.
When requesting a quote, please indicate as many of the options you desire. Our marketing team is committed to working with you to build-out a battery enclosure solution that meets all your requirements.