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Battery Technology for Data Centers and Network Rooms P a g e | 1 
 
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Battery Technology for Data Centers and Network Rooms 
Transcript 
 
Slide 1 
Welcome to the course on Battery Technology for Data Centers and Network Rooms: An Overview. 
 
Slide 2: Welcome 
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allow you to navigate through the eLearning experience. Using your browser controls may disrupt the 
normal play of the course. Click the attachments link to download supplemental information for this course. 
Click the Notes tab to read a transcript of the narration. 
 
Slide 3: Learning Objectives 
At the completion of this course, you will be able to: 
• Describe how a battery works 
• Recognize how batteries support data center loads 
• Identify the major categories of data center batteries 
• Learn how to plan and prepare for battery installations and 
• Discuss battery lifecycle costs 
 
Slide 4: Introduction 
As a way of introduction, let’s discuss why batteries are used in the data center. 
 
Batteries ensure that, in the event of a power failure, critical systems will continue to run without interruption. 
Although energy reserve technologies such as fuel cells, flywheels, and Nickel Cadmium batteries are 
currently being explored, the lead-acid battery is the predominant choice for energy storage. Integrated 
within or connected to Uninterruptible Power Supply (UPS), batteries provide the backbone of most data 
center power backup solutions. Over 10 million UPSs are presently installed utilizing one of the three main 
types of batteries: Flooded, Valve Regulated Lead Acid (VRLA), and Modular Battery Cartridge (MBC) 
systems. Now let’s examine how a battery works. 
 
Slide 5: Introduction 
 
 
 
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A battery is designed to store electricity for later use. Inside the battery, a chemical reaction is created when 
positive and negative plates are immersed into an electrolyte (made up of sulfuric acid and water) resulting 
in the development of a voltage. Electricity flows from the battery once a circuit is introduced between the 
positive and negative terminals. Batteries are always either in a state of charge or recharge. Once a battery 
begins to discharge its electricity, the voltage drops and the battery will need to be recharged. In the event 
of a power outage, commercial data center batteries supply electrical power to feed critical systems. 
Examples of systems that require battery back up power are hospitals and telecommunications systems. 
 
Slide 6: Types of Batteries 
Three types of lead acid batteries are generally available in the marketplace today. The three categories 
include flooded batteries, Valve Regulated Lead Acid (VRLA) batteries and Modular Battery Cartridge (MBC) 
batteries. Flooded batteries are also referred to as vented or wet cell batteries. For the sake of consistency 
this course will refer to this battery type as flooded. 
 
The flooded battery is the oldest of the technologies. Commonly used in automotive and marine 
applications, this technology is predominantly used in UPS applications above 400kW. 
 
VRLA batteries have been utilized for approximately 20 years. This technology offers a higher power 
density and lower capital costs than traditional flooded cell solutions. VRLA batteries are typically deployed 
within power systems rated below 400kW. 
 
MBC battery technology was introduced several years ago. This solution utilizes modular, multi-cell VRLA 
cartridges arranged in a parallel-series architecture that allows for easy installation and replacement. 
Let’s take a more in depth look at each battery type. 
 
Slide 7: Flooded 
Flooded batteries share a number of common characteristics. 
 
They have a non-sealed system for ease of serviceability. Because of this, they continuously vent hydrogen 
and oxygen. Flooded batteries require periodic water replenishment. Electrolyte, which is a combination of 
sulfuric acid and water, is stored within the flooded battery in liquid form. Flooded batteries are usually too 
heavy to be lifted manually. They are housed in a transparent container to allow plate inspection and they 
operate at high currents. The batteries are connected by large bolted terminals. They are stored in open 
 
 
 
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frames or large cabinets. They require both spill containment and hydrogen detection. The typical lifespan of 
a flooded battery, if properly maintained, is 15-20 years. Finally, the flooded battery is usually considered 
part of the facility meaning that they are not intended to be moved from their original location 
 
Slide 8: VRLA 
Valve Regulated Acid Batteries, VRLA are built in a sealed system. They are housed in an opaque container. 
Because the system is enclosed, the electrolyte is immobilized. The process of hydrogen & oxygen 
recombining happens internally. This makes spillage much less likely if compared to flooded batteries. The 
“starved electrolyte” makes it weigh much less than flooded cells. 6- and 12-volt VRLA batteries are typical 
and are often utilized as part of small & medium UPS systems. They are connected by bolted terminals or 
quick-connects and stored in open frames or large cabinets. They feature built in pressure relief valves 
which open under fault conditions. The typical lifespan of a VRLA battery is about 5 years. This type of 
battery is usually considered part of the electronic equipment. 
 
Slide 9: MBC 
MBC batteries are built in a sealed system. The electrolyte is immobilized by absorbent glass mats. The 
battery contains thin lead plates for a high-rate of discharge. MBC batteries are typically used in multi-string 
(redundant) applications. They contain an enclosed modular cartridge. This type of battery can be easily 
attached to a Common DC bus. The batteries are plugged into pre-manufactured battery racks. The 
batteries contain both temperature and monitoring sensors. 
 
Slide 10: Planning Battery Installations 
Battery options are considered when a data center is being planned and designed. Once the data center 
power and runtime requirements have been determined, the proper battery technology can be chosen. 
 
Six main issues need to be considered when choosing a battery technology. Those six issues include 
battery engineering, weight, space, installation, security, and maintenance. 
 
Now that you have had a chance to review the attached table, let’s discuss the fire code considerations. 
 
Slide 11: Fire Code Considerations 
Proper interpretation of the fire codes is essential in the design and implementation of data centers, network 
rooms and battery rooms. In some cases, fire codes do not clearly recognize improvements in battery safety 
 
 
 
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resulting from recent changes in data center battery technology. VRLA and MBC batteries are frequently 
deployed within data centers and network rooms without the need for the elaborate safety systems that are 
required for flooded batteries. 
 
Slide 12: Fire Code Considerations 
The two main fire codes relating to battery systems are the Uniform Fire Code (UFC) and the International 
Fire Code (IFC). 
 
Model codes are written by organizations and publishedevery few years. A locality, town, county, or state, 
can choose which code (and which version of the code) to adopt and enforce. Checking with the local safety 
inspector is the best method for determining which code applies to a specific installation. Local authorities 
also have the jurisdiction to modify the codes. Under these codes, battery systems may be subject to 
special installation requirements, depending upon the amount of electrolyte and the nature of the battery 
technology. 
 
Before we move onto hazardous materials considerations, let’s take a moment to review what we have just 
covered. 
Slide 13: Hazardous Materials Considerations 
As with the fire codes, it is extremely important to identify any hazardous material codes that exist when 
deploying any type of battery installation. Most commercial applications of stationary lead-acid batteries will 
fall well below the reporting quantities required by the EPA. Flooded batteries are more likely than VRLA 
batteries to require reporting, whether for reporting inventory or for registering the presence of hazardous 
materials. Large battery farms can add significantly to a company’s compliance work. Although spills or 
releases of hazardous material (hazmat) from batteries at the reporting threshold are quite rare, one must 
nevertheless report the presence of battery inventories in the building to local and state authorities, and one 
must have an emergency preparedness plan in place. 
 
Slide 14: Hazardous Materials Consideration 
For lead acid batteries, environmental compliance focuses on the amount of sulfuric acid and lead at a 
particular location. Power ratings for VRLA batteries and MBCs are much higher than for flooded batteries 
at the same reporting threshold. For example, when two battery systems of approximately equal ampere-
hour batteries were compared, it took only 147 cells of the flooded battery to reach the 500 pound 
government reporting requirement threshold, whereas it took 746 cells of VRLA batteries to reach the same 
 
 
 
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threshold (i.e., five times as many VRLA batteries). It is important to understand the requirements of the 
Environmental Protection Agency (EPA) and the Occupational Safety and Health Agency (OSHA). These 
two agencies want to know the quantities of substances that could be dangerous to employees or neighbors. 
If a site has a few hundred battery containers full of lead and sulfuric acid, it is certainly a likely candidate for 
review. The Internet is a good source of information regarding battery regulations. Those who have had 
dealings with government agencies in the past already know that no single contact source can address all 
issues related to batteries. However, a good initial reservoir of information can be found at the website 
www.epa.gov. 
 
Slide 15: Hazardous Materials Considerations 
Every community in the United States must be part of a comprehensive plan to prepare for and respond to 
emergencies involving hazardous substances. The governor of each state designates a State Emergency 
Response Commission (SERC) that is responsible for implementing the Emergency Planning and 
Community Right-to-Know Act (EPCRA) provisions within the state. Under the supervision of the SERCs are 
some 3,500 emergency planning districts, and within each of those is a Local Emergency Planning 
Commission (LEPC). LEPC’s members usually include representatives of local fire department, police, civil 
defense, public health, transportation and environmental agencies, as well as representatives of affected 
large facilities, community groups and media. LEPC’s must develop an emergency plan, called an 
Emergency Response Plan, review it annually, and provide information about chemicals that are present in 
the community to its citizens. 
 
Slide 16: Hazardous Materials Considerations 
It is imperative to understand the Code of Federal Regulations prior to installing any batteries into your data 
center or network room. The regulations in place may impact the ultimate decision regarding which type of 
battery to utilize in the data center. The Environmental Protection Agency (EPA) Emergency Planning and 
Community Right-to-know Act (EPCRA) requires owners to inform local authorities when their facilities have 
large volumes, which are actually reported in weight, of hazardous materials such as sulfuric acid which is 
present in lead-acid battery electrolyte. For a more in depth look at these regulations please consult the 
Data Center University course entitled Battery Safety and Environmental Concerns. 
 
Let’s next take a look at site considerations. 
 
Slide 17: Site Preparation Work 
 
 
 
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Because every battery installation is unique, many factors need to be considered when preparing a site for 
battery installation. One factor to consider is the amount of engineering required to deploy the battery 
solution. New construction would require the most engineering, while upgrades usually involve less 
engineering. Flooded batteries, which must be in dedicated rooms with dedicated ventilation and spill 
containment, require the most engineering. VRLA batteries require moderate to no engineering, while MBC 
batteries require the least. 
 
 
 
Slide 18: Site Preparation Work 
Another site preparation consideration is the weight of the equipment that will be housed in the data center 
or network rooms. Lead acid batteries are very heavy. Floor loading and ease of handling should also be 
considered. As VLRA batteries and MBC batteries can be located in IT rooms, access floor loading must 
also be addressed. It is imperative to make sure that any flooring the equipment will be passing over can 
tolerate the weight of that equipment. 
 
Slide 19: Site Preparation Work 
Another site preparation consideration is the space necessary for the required equipment. Maximizing the 
use of space is a top priority for many data centers. Historically, a company would install a large mainframe 
and keep it in use for 15 years. Today faster and smaller equipment is installed daily in the data center. 
 
Space planning is difficult, as forecasts for data center space may be revised considerably over time. In 
many cases the actual space utilization falls short of forecasts and rigid designs have become a serious 
liability. Batteries are a large component of the infrastructure and the right technology chosen for the right 
situation can represent a substantial savings in space. 
 
Slide 20: Site Preparation Work 
It is also important to consider safety when preparing a site. All batteries represent a hazard and must be 
handled with care. The batteries for UPS operation are connected in series or parallel strings creating 
hazardous voltages and high levels of amp hour capacity. 
 
 
 
 
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Because of the presence of high DC voltage a serious potential electrical shock hazard exists. This hazard 
will always be present, even when the battery system is off-line. Another concern is that batteries have low 
internal impedances and are capable of very high levels of short circuit current. 
 
Because flooded cell batteries are located in open battery racks they should be in a secure area away from 
all untrained persons. The battery room should have restricted access to prevent any unauthorized entrance. 
VRLA batteriesare usually behind a cabinet door. Only authorized persons trained in the maintenance of 
batteries and the UPS should have access inside the cabinet. 
 
MBCs are packaged to reduce the risk of shock and are approved by independent testing laboratories for 
handling. 
 
Next, let’s discuss ventilation and safety regulations. 
 
Slide 21: Ventilation and Safety Regulations 
All battery types work on the principle of a chemical reaction between positive and negative plates. 
Because the battery technology types vary, they have different considerations for ventilation under the same 
operating mode. 
 
One important consideration is the storage of the different battery types. With shipping plugs removed, 
flooded batteries can give off minor amounts of hydrogen and oxygen due to normal evaporation of water 
depending upon the amount of ambient heat and air humidity. This evaporation does not occur with sealed 
VRLA and MBCs battery types. 
In back-up applications the batteries are kept at a constant state of maximum potential (called float voltage) 
in order to ensure maximum power reserve. The constant presence of voltage causes batteries to 
continuously create hydrogen and oxygen. With flooded batteries, some of the hydrogen gas is released into 
the room. Flooded lead acid batteries vent approximately 60 times more hydrogen than comparably rated 
VRLA batteries. With both VRLA and MBCs, hydrogen recombines into the water inside the battery. 
 
Slide 22: Ventilation and Safety Regulations 
Battery discharge is another consideration when discussing ventilation. High ambient temperature will 
cause more chemical reaction and longer run times, whereas low ambient temperature produces the 
opposite effect. The battery generates little heat. However, the power electronics supported by the battery 
 
 
 
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might run slightly hotter during a discharge. With all three battery types, flooded, VRLA, and MBC little or no 
gas is vented during discharge. 
Ventilation is also needed during battery recharge. Flooded batteries release the most hydrogen into a room 
during recharge while VRLA and MBCs are vulnerable to overheating if voltage and/or ambient temperature 
exceeds recommended levels. 
 
Next let’s discuss some code requirements of each battery technology. 
 
Slide 23: Ventilation and safety Regulations 
In a data center, or any facility in which electrical equipment and battery systems are installed, the 
ventilation system must address the following areas: 
• Health safety - The air must be free of pollutants that could be toxic, corrosive, poisonous, or 
carcinogenic. 
• Fire safety - The system must prevent and safely remove the accumulation of gasses or aerosols 
that could be flammable or explosive. 
• Equipment reliability and safety - The system must provide an environment that optimizes the 
performance of equipment (including both batteries and electronic equipment) and maximizes their 
life expectancy and finally 
• Human comfort 
• The ventilation system must also be coordinated with the requirements of a fire prevention and 
suppression system. 
 
Slide 24: Ventilation and Safety Regulations 
Cleanliness of Air is critical to ensuring a safe environment. According to the Institute of Electrical and 
Electronics Engineers (IEEE) all battery manufacturers as well as all best practices recommend that 
batteries be clean. Flooded batteries are more vulnerable than VRLA batteries to build-up of oils and dust. 
Air changes are necessary for the data center or network room. 
 
Hydrogen Accumulation is another important consideration. In any space, hydrogen should not be allowed 
to accumulate to greater than two percent concentration. Most regulations stipulate a maximum 
concentration of only one percent. VRLA batteries and MBCs do not vent unless they are forced into a 
failure mode. 
 
 
 
 
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Finally, monitoring & instrumentation are essential to the overall health of a data center or network room. 
Where mechanical ventilation is used, monitors are recommended to detect and sound an audible alarm 
upon loss of air movement, fan failure and/or closure of fire or smoke dampers. 
Now let’s take a look at an analysis of battery lifecycle costs. 
 
Slide 25: Analyzing Battery Lifecycle Costs 
The expense of compliance with safety codes limits the use of flooded batteries to larger installations, 
usually above 400kW. The cost of having a controlled access room, spill containment, and the space 
required for maintenance, represent a large, immovable, fixed cost. 
 
VLRA batteries offer a more flexible solution. The lower level of electrolyte usually eliminates the need for 
expensive regulatory compliance. These batteries can require smaller service clearances, can be moved 
because they don’t spill, and can be contained within a locked cabinet. These benefits allow for greater 
flexibility and reduced cost. Design considerations must be made for replacement, as their life expectancy 
is only about 5 years. 
 
MBCs have all the advantages of VRLA with even more flexibility. The service clearances, while still 
required, can be incorporated more efficiently. The “plug in” nature of the design reduces wiring and 
connection clearances. The MBC and its cabinets can be easily moved and replaced. 
 
 
 
 
 
 
As shown in this table, flooded cells have approximately 3 times the expected life of VRLA or MBC battery 
systems. This is contingent upon the flooded batteries receiving proper maintenance over their lifetime with 
 
 
 
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the assumption that all batteries are from a quality manufacturer. 
 
Another consideration that needs to be addressed is purchase costs. 
 
Slide 26: Purchase Costs 
A number of factors should be considered prior to purchasing the battery solution. These factors include the 
cost of the battery itself, the cost of the battery frame, and the cost of installation. 
 
Let’s consider the costs for an 80kW scenario. The initial battery cost for a flooded battery system is 
approximately $20,000 which is substantially more than the cost of a VRLA system of $10,000 and an MBC 
system of $12,000. The cost of the battery frame for the 80 kW units would be $4,000 for a flooded battery 
system and $3,000 for either the VRLA or the MBC system. 
 
The next factor to consider would be installation and start up costs. The flooded battery installation cost 
would be approximately $4,000, the VRLA would run about $2,000 and the MBC would be about $1,000. 
 
For a more in depth look at these and other factors you may want to take our course on options and lifecycle 
costs titled: Data Center Backup Batteries: Options and Lifecycle Costs. 
 
Now let’s take a look at maintenance costs as well as the costs associated with spill containment. 
Slide 27: Maintenance Costs 
The maintenance costs for a flooded battery option can be substantially greater than that of the VRLA 
battery option. If we look at the 80kW ten minute solution we see that the maintenance costs for the flooded 
battery are approximately $30,000 over the lifetime of that battery as compared to the VRLA battery costs 
which are approximately $15,000. Looking at the MBC lifetime maintenance costs we see an even more 
substantial savings. The estimated maintenance costs for the MBC battery are $0.Battery Technology for Data Centers and Network Rooms P a g e | 11 
 
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It is evident from this data that, when considering lifetime maintenance costs for different battery types, the 
cheapest option would be the MBC battery solution. 
 
Another item to consider along with maintenance costs is the cost of spill containment in the event of 
leakage. With the 80kW solution the cost of spill containment for the flooded battery is $3,000. There is no 
cost associated with spill containment in either the VRLA or MBC batteries as they are enclosed. 
 
It is also important to consider battery replacement costs. There are no replacement costs for the flooded 
battery due to the fact that the life expectancy for a flooded battery is approximately 10-15 years. As 
discussed previously, because of the fact that both VRLA and MBC batteries have an estimated lifecycle of 
5-7 years it is imperative to consider the replacement costs for those solutions when looking at overall 
lifecycle costs. The replacement costs for the VRLA battery are $20,000 and the MBC is $24,000. 
 
Slide 28: Disposal Costs 
Another consideration when looking at the battery lifecycle costs is the cost of battery disposal. 
 
Again as we look at the 80kW solution, the cost for disposal for both the flooded and VRLA batteries would 
be approximately $6,000. The MBC disposal cost is approximately $4,000. 
 
Disposal of batteries must be carefully controlled. Some battery manufacturers will pick up expired batteries 
free of charge just so they can recycle the lead and plastics for use in new batteries. It is important to obtain 
and save complete documentation certifying that the batteries have been properly recycled. Even if 
someone has a good-faith document showing that the batteries were picked up and properly disposed of, 
they are still designated as a Potentially Responsible Party (PRP) and may be liable for substantial clean-up 
fees if the batteries later turn up in a toxic waste site. 
 
Slide 29: Usage Rates 
It is important to understand the nature of battery usage rates in order to ensure the longest life and highest 
performance possible from each battery type. Anytime a battery is in use, whether during a power outage or 
for any other reason, the batteries expected lifecycle will be shortened. Therefore, it is extremely important 
to make sure that the battery output is monitored to ensure that enough stored power capacity exists to 
manage a future outage. 
 
 
 
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Slide 30: Summary 
• A thorough review of the three main battery types reveals that MBC battery solutions can offer 
more than a 50% savings over VRLA and flooded batteries. When the infrastructure costs and the 
traditional battery purchase costs are factored in, the differences in lifecycle savings that can be 
accrued is dramatic. This is why over 99% of UPSs sold each year worldwide utilize either VRLA or 
MBC batteries. 
• Factors relating to system availability have driven some installations to deploy flooded cells despite 
the lower life cycle cost of VRLA or MBC batteries. The technology of the MBC battery system 
specifically addresses many of these issues. 
• When compared with flooded cell battery systems, the MBC can save over 90% in life cycle costs 
in a real-world situation. Most of this cost advantage results from the ability to size the battery 
system to the current requirement and add as needed to meet changing requirements. 
• In cases where the ultimate load value is pre-determined and full utilization is achieved at the first 
commissioning of the system, much of the advantage of the MBC battery system is lost. However, 
the engineering, installation, and maintenance cost advantages still provide a savings of up to 60% 
when compared with flooded cells. 
Slide 31: Thank You! 
Thank you for participating in this Data Center University™ course.