Difference between revisions of "Mercury cells"

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'''Mercury cells''' (also referred to as mercury batteries) are batteries with a mercury oxide electrode. The manufacture, transport or sale of these batteries is banned or restricted in many jurisdictions, though some are still made in Russia. Before such bans, many cameras and lightmeters were designed to use them. Because mercury batteries produced a constant and reliable voltage, these devices were built without voltage regulation circuitry. Unless remedial measures are taken, use of other kinds of batteries gives inaccurate meter readings and therefore incorrect exposures.
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'''Mercury cells''' (also referred to as mercury batteries) are batteries with a mercury oxide electrode. Mercury batteries were discovered in the 19th century, and a practical method to make small button batteries was discovered by Ruben and Mallory.<ref>[https://www.electrochem.org/dl/interface/fal/fal06/fall06_p16-17.pdf Samuel Ruben: Inventor, Scholar, and Benefactor] Electrochemical Society Journal Fall 2006</ref>  These type of battery use the reaction between mercuric oxide and zinc electrodes in an alkaline electrolyte. The biggest advantage of these batteries is that the voltage during discharge remains practically constant at 1.35 volts.  
  
 
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After WWII these batteries were very popular, as they could deliver constant and reliable voltage in a small format (button) they were used for toys, cameras, and even pacemakers and hearing aids. 
==Devices requiring a PX625 battery==
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Research carried outin the 1970s proved that ingestion of batteries could cause severe illness in kids, and that the toxicity of Mercury was leaching off landfills into streams.  Mercury batteries were banned, except for medical and military use, in most countries. 
Many cameras and lightmeters where designed for and require a [[PX625|625 mercury cell]] (see a [[PX625_cameras|list of cameras]] and [[PX625_exposure_meters|list of exposure meters]]). Some cameras and exposure meters were designed for 625 sized cells but include voltage regulation circuitry and thus do not require a PX625 to function properly ([[non_Hg_devices|list of devices]]).
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In the 21st century, manufacture, transport or sale of these batteries is banned or restricted nearly worldwide, due to the metal's toxicity; although some are still made in Russia. Alkaline, lithium and other batteries have replaced mercury cells in most applications.  However, before such bans, many cameras and lightmeters were designed to use them. Because mercury batteries produced a constant and reliable voltage over the life of the battery (discharge curve), these devices were built without voltage regulation circuitry. Use of other kinds of batteries, that have different discharge curves over time, without regulation circuitry may lead to inaccurate meter readings and therefore incorrect exposures and must be taken into account.
  
 
==Cell names and sizes==
 
==Cell names and sizes==
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==Devices requiring mercury batteries==
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Many cameras and lightmeters where designed for and require a [[PX625|625 mercury cell]], PX675 or 400 cells (see a [[PX625_cameras|list of cameras]] and [[PX625_exposure_meters|list of exposure meters]]). Some cameras and exposure meters were designed for 625, 675, or 400 sized cells but include voltage regulation circuitry and thus do not require a Mercury Cell to function properly ([[non_Hg_devices|list of devices]]).
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==Mercury battery replacement==
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This is a problem that many owners of vintage equipment face. 
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* Zinc-air batteries used for hearing aids, produce 1.35V and have a similar discharge curve than mercury batteries but their life is short
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* Silver oxide or Alkaline batteries, produce 1.55V and might not be suitable for non-voltage regulated equipment
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* Adapter circuitry can be bought from several suppliers.  Some of the adapters use a Schottky diode to reduce the voltage <ref>[https://www.butkus.org/chinon/batt-adapt-us.pdf The mercury Battery problem by FP De Gruijter] page 8-10</ref>.
  
 
==External links==
 
==External links==
  
*[http://rick_oleson.tripod.com/index-111.html Suggestions] from Rick Oleson (based on ideas from <!-- http://topconcollection.home.att.net/index.html Dead link --> Leon Schoenfeld) to make classic cameras give acceptable meter readings using modern alkaline batteries.
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*[http://rick_oleson.tripod.com/index-111.html Suggestions] from Rick Oleson (based on ideas from <!-- http://topconcollection.home.att.net/index.html Dead link --> Leon Schoenfeld) to make classic cameras give acceptable meter readings using zinc-air hearing aid batteries.
*[http://rick_oleson.tripod.com/batt_adapt_us.pdf The mercury cell problem and its solutions] (PDF file) by F. de Gruijter. Also discusses PX675 and other mercury batteries.
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*[http://rick_oleson.tripod.com/batt_adapt_us.pdf The mercury cell problem and its solutions] (PDF file) by F. de Gruijter. Also discusses PX675 and other mercury batteries. [https://www.butkus.org/chinon/batt-adapt-us.pdf Available from Butkus's orphan camera as well]
 
*[http://www.buhla.de/Foto/eQuecksilber.html The mercury oxide battery problem], at [http://www.buhla.de/Foto/Konica/eKonicaStart.html Konica SLR system], providing information about the PX625 and PX675 battery that is not specific to Konica models
 
*[http://www.buhla.de/Foto/eQuecksilber.html The mercury oxide battery problem], at [http://www.buhla.de/Foto/Konica/eKonicaStart.html Konica SLR system], providing information about the PX625 and PX675 battery that is not specific to Konica models
*Notes on using zinc-air hearing aid batteries to replace mercury cells [http://silverbased.org/zinc-mercury-replacement/ part 1] and [http://silverbased.org/zinc-air-voltage/ part 2] from [http://silverbased.org/ Silverbased]
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*Quirks of using zinc-air hearing aid batteries to replace mercury cells [https://web.archive.org/web/20160406175042/http://silverbased.org/zinc-mercury-replacement/ part 1] and [https://web.archive.org/web/20160411045929/http://silverbased.org/zinc-air-voltage/ part 2] from [https://web.archive.org/web/20160408110648/http://silverbased.org/ Silverbased (Archived)]
 
*[http://data.energizer.com/ Energizer Battery Online Data]
 
*[http://data.energizer.com/ Energizer Battery Online Data]
*[http://www.myoldcamera.com/index.html My Old Camera]  Source for 1.35 volt zinc-air alternative to mercury cells 625, 675, 400
 
*[http://www.vintagebatteries.com/index.html VintageBatteries.com]  Seller of 1.35 volt zinc-air replacements to mercury cells PX625, PX400, PX27, PX640 etc.
 
 
*[http://www.px625.ru/index.html Russian mercury px625 battery] Seller of PX625 mercury batteries.
 
*[http://www.px625.ru/index.html Russian mercury px625 battery] Seller of PX625 mercury batteries.
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==Notes==
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<references/>
  
 
==References==  
 
==References==  
  
''Popular Photography'', October 1993, p. 130; January 1994, p. 144; September 1994, p. 144; and August 1995, p. 66.
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* ''Popular Photography'', October 1993, p. 130; January 1994, p. 144; September 1994, p. 144; and August 1995, p. 66.
 
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* Hintz, Eric S. 2009. "Portable Power: Inventor Samuel Ruben and the Birth of Duracell" Technology and Culture Vol. 50, No. 1 (Jan., 2009), pp. 24-57 (34 pages). Published By: The Johns Hopkins University Press Available at [https://www.jstor.org/stable/40061566 jstore.org]
 
[[Category: Batteries]]
 
[[Category: Batteries]]

Latest revision as of 21:38, 9 February 2023

Mercury cells (also referred to as mercury batteries) are batteries with a mercury oxide electrode. Mercury batteries were discovered in the 19th century, and a practical method to make small button batteries was discovered by Ruben and Mallory.[1] These type of battery use the reaction between mercuric oxide and zinc electrodes in an alkaline electrolyte. The biggest advantage of these batteries is that the voltage during discharge remains practically constant at 1.35 volts.

After WWII these batteries were very popular, as they could deliver constant and reliable voltage in a small format (button) they were used for toys, cameras, and even pacemakers and hearing aids. Research carried outin the 1970s proved that ingestion of batteries could cause severe illness in kids, and that the toxicity of Mercury was leaching off landfills into streams. Mercury batteries were banned, except for medical and military use, in most countries. In the 21st century, manufacture, transport or sale of these batteries is banned or restricted nearly worldwide, due to the metal's toxicity; although some are still made in Russia. Alkaline, lithium and other batteries have replaced mercury cells in most applications. However, before such bans, many cameras and lightmeters were designed to use them. Because mercury batteries produced a constant and reliable voltage over the life of the battery (discharge curve), these devices were built without voltage regulation circuitry. Use of other kinds of batteries, that have different discharge curves over time, without regulation circuitry may lead to inaccurate meter readings and therefore incorrect exposures and must be taken into account.

Cell names and sizes

Mercury batteries came in number of different sizes including the 32, 400, 625, 640, 675 and the like. Most of the mercury batteries are a single electrolytic cell - usually small and circular. However, the 32 is a set of 4 stacked 640 cells. The greatest number of cameras, finders and light meters were designed for the PX625.

Common number Alternative names Diameter (mm) Height (mm) Weight (g)
625 1124MP, MR9, PX625, PX13, EPX625, RPX625, KX625, HD625, PN625, RM625, 625, H1560, H-D, MR9 15.6 6.05 4.5
675 1128MP, MR44, PX675, HD675, KX675, RPX675, H-C 11.6 5.35 2.6
400 1116M, MR42, E400N, EPX400, KX400, PM400R, PX400, RM400, T400N, V400PX 11.6 3.6 1.4
640 1105M, NR52 16 11.2 8
32 1404M, 4NR52, PX32, E164, TR164, 4NR52, 1404M. HM-4N, V164PX, PX32A, PX32B 17 44.5 36


Devices requiring mercury batteries

Many cameras and lightmeters where designed for and require a 625 mercury cell, PX675 or 400 cells (see a list of cameras and list of exposure meters). Some cameras and exposure meters were designed for 625, 675, or 400 sized cells but include voltage regulation circuitry and thus do not require a Mercury Cell to function properly (list of devices).

Mercury battery replacement

This is a problem that many owners of vintage equipment face.

  • Zinc-air batteries used for hearing aids, produce 1.35V and have a similar discharge curve than mercury batteries but their life is short
  • Silver oxide or Alkaline batteries, produce 1.55V and might not be suitable for non-voltage regulated equipment
  • Adapter circuitry can be bought from several suppliers. Some of the adapters use a Schottky diode to reduce the voltage [2].

External links

Notes

References

  • Popular Photography, October 1993, p. 130; January 1994, p. 144; September 1994, p. 144; and August 1995, p. 66.
  • Hintz, Eric S. 2009. "Portable Power: Inventor Samuel Ruben and the Birth of Duracell" Technology and Culture Vol. 50, No. 1 (Jan., 2009), pp. 24-57 (34 pages). Published By: The Johns Hopkins University Press Available at jstore.org