View source for Battery room

{{Short description|Room that houses batteries for power systems}}
[[File:Fort «Furggels» - Battery Power Supply (5166616214).jpg|thumb|Battery room]]

A '''battery room''' is a room that houses [[Battery (electricity)|batteries]] for backup or uninterruptible [[power system]]s. The rooms are found in [[telecommunication]] [[Telephone exchange|central offices]], and provide standby power for computing equipment in [[datacenter]]s. Batteries provide [[direct current]] (DC) electricity, which may be used directly by some types of equipment, or which may be converted to [[alternating current]] (AC) by [[uninterruptible power supply]] (UPS) equipment. The batteries may provide power for minutes, hours or days, depending on each system's design, although they are most commonly activated during brief electric utility outages lasting only seconds.

Battery rooms were used to segregate the fumes and corrosive chemicals of [[wet cell]] batteries (often [[Lead–acid battery|lead–acid]]) from the operating equipment, and for better control of temperature and ventilation. In 1890, the [[Western Union]] central [[Western Union Telegraph Building (New York)|telegraph office in New York City]] had 20,000 wet cells, mostly of the primary zinc-copper type.<ref>{{cite web|url=https://books.google.com/books?id=N-pQAAAAYAAJ&dq=%22battery+room%22&pg=PA425|title=Electrical Engineer|author=|date=16 January 1890|publisher=Electrical Engineer.|access-date=16 January 2019|via=Google Books|page=425}}</ref>

== Telecommunications ==
Telephone system central offices contain large battery systems to provide power for customer telephones, telephone switches, and related apparatus.<ref name=NFPA18/> Terrestrial microwave links, cellular telephone sites, fibre optic apparatus and satellite communications facilities also have standby battery systems, which may be large enough to occupy a separate room in the building. In normal operation power from the local commercial utility operates telecommunication equipment, and batteries provide power if the normal supply is interrupted. These can be sized for the expected full duration of an interruption, or may be required only to provide power while a standby generator set or other emergency power supply is started.

Batteries often used in battery rooms are the flooded [[lead-acid battery]], the [[VRLA battery|valve regulated lead-acid battery]] or the [[nickel–cadmium battery]]. Batteries are installed in groups. Several batteries are wired together in a series circuit forming a group providing DC electric power at 12, 24, 48 or 60 volts (or higher). Usually there are two or more groups of series-connected batteries. These groups of batteries are connected in a parallel circuit. This arrangement allows an individual group of batteries to be taken offline for service or replacement without compromising the availability of uninterruptible power. Generally, the larger the battery room's electrical capacity, the larger the size of each individual battery and the higher the room's DC voltage.

==Electrical utilities==
Battery rooms are also found in electric [[power plant]]s and [[Electrical substation|substation]]s where reliable power is required for operation of [[switchgear]], critical standby systems, and possibly [[black start]] of the station.<ref name=BH06>Colin Bayliss, Brian Hardy ''Transmission and Distribution Electrical Engineering'' Elsevier, 2006, {{ISBN|0080468136}} pp. 121-124</ref>  Often batteries for large switchgear line-ups are 125 V or 250 V nominal systems, and feature redundant battery chargers with independent power sources. Separate battery rooms may be provided to protect against loss of the station due to a fire in a battery bank. For stations that are capable of black start, power from the battery system may be required for many purposes including switchgear operations.

Very large utility batteries may be used for [[grid energy storage]].

== Submarines and ocean-going vessels ==
[[File:USS_S-5_(SS-110)-_from_the_US_Navy_-_1920_.gif|thumb|right|Side view of S-class submarine, [[USS S-5 (SS-110)]], of the United States Navy]]
Battery rooms are found on diesel-electric [[submarine]]s, where they contain the lead-acid batteries used for undersea propulsion of the vessel. Even nuclear submarines contain large battery rooms as backups to provide maneuvering power if the nuclear reactor is shut down. Batteries in surface vessels may also be contained in a battery room.

Battery rooms on ocean-going vessels must prevent seawater from contacting battery acid, as this could produce toxic [[Chlorine|chlorine gas]].<ref>Norman Friedman ''U.S. Submarines Through 1945: An Illustrated Design History'', Naval Institute Press, 1995 {{ISBN|1-55750-263-3}}, p. 361</ref>
This is of particular concern on submarines.<ref>{{Cite report |author=National Research Council (U.S.) |date=2002 |title=Review of Submarine Escape Action Levels for Selected Chemicals |url=https://books.google.com/books?id=eUcWSXV02YQC&q=Review+of+Submarine+Escape+Action+Levels+for+Selected+Chemicals |publisher=National Academies Press |page=2 |isbn=0309082943}}</ref>

== Design issues ==
Since several types of [[Secondary battery|secondary batteries]] give off [[hydrogen]] if overcharged, ventilation of a battery room is critical to maintain the concentration below the lower [[explosive limit]]. The number of air changes per hour required to prevent unsafe accumulation can be calculated from the number of cells and the charging current, given the chemistry of the battery.<ref name=BH06/>

The life span of secondary batteries is reduced at high temperature and the energy storage capacity is reduced at low temperature, so a battery room must have heating or cooling to maintain the proper temperature.

Batteries may contain large quantities of corrosive [[electrolyte]]s such as [[sulfuric acid]] used in lead-acid batteries or caustic potash (aka [[potassium hydroxide]]) used in [[Nickel-cadmium battery|NiCd batteries]]. Materials of the battery room must resist corrosion and contain any accidental spills. Plant personnel must be protected from spilled electrolyte.  In some jurisdictions, large battery systems may contain reportable amounts of sulfuric acid, a concern for fire departments.<ref name=NFPA18>[[National Fire Protection Association]], ''Fire Protection Handbook Eighteenth Edition'', NFPA 1997 {{ISBN|0-87765-377-1}}; pp. 9-199 9-203</ref>  Battery rooms in industrial and utility installations typically have an eye-wash station or decontamination showers nearby, so that workers who are accidentally splashed with electrolyte can immediately wash it away from the eyes and skin.

== See also ==
* [[List of battery types]]
* [[Battery storage power station]]

== References ==
<references />

== Further reading ==
{{commons category}}
* Kusko, Alexander (1989). ''Emergency/Standby Power Systems'', pp.&nbsp;99–117. New York: McGraw-Hill Book Co., {{ISBN|0-07-035689-0}}.
* National Fire Protection Association (2005). 'NFPA 111: Standard on Stored Electrical Energy Emergency and Standby Power'

[[Category:Battery (electricity)|Room]]
[[Category:Electric power]]
[[Category:Rooms]]
[[Category:Telecommunications infrastructure]]