In many devices that use batteries -- such as portable radios and flashlights -- you don't use just one cell at a time. You normally group them together in a serial arrangement to increase the voltage or in a parallel arrangement to increase current. The diagram shows these two arrangements.
The upper diagram shows a parallel arrangement. The four batteries in parallel will together produce the voltage of one cell, but the current they supply will be four times that of a single cell. Current is the rate at which electric charge passes through a circuit, and is measured in amperes. Batteries are rated in amp-hours, or, in the case of smaller household batteries, milliamp-hours (mAH). A typical household cell rated at 500 milliamp-hours should be able to supply 500 milliamps of current to the load for one hour. You can slice and dice the milliamp-hour rating in lots of different ways. A 500 milliamp-hour battery could also produce 5 milliamps for 100 hours, 10 milliamps for 50 hours, or, theoretically, 1,000 milliamps for 30 minutes. Generally speaking, batteries with higher amp-hour ratings have greater capacities.
The lower diagram depicts a serial arrangement. The four batteries in series will together produce the current of one cell, but the voltage they supply will be four times that of a single cell. Voltage is a measure of energy per unit charge and is measured in volts. In a battery, voltage determines how strongly electrons are pushed through a circuit, much like pressure determines how strongly water is pushed through a hose. Most AAA, AA, C and D batteries are around 1.5 volts.
Imagine the batteries shown in the diagram are rated at 1.5 volts and 500 milliamp-hours. The four batteries in parallel arrangement will produce 1.5 volts at 2,000 milliamp-hours. The four batteries arranged in a series will produce 6 volts at 500 milliamp-hours.
Battery technology has advanced dramatically since the days of the Voltaic pile. These developments are clearly reflected in our fast-paced, portable world, which is more dependent than ever on the portable power source that batteries provide. One can only imagine what the next generation of smaller, more powerful and longer-lasting batteries will bring.
For more information on batteries and related topics, check out the links below.
- Quiz Corner: Batteries Quiz
- How Lithium-ion Batteries Work
- How Circuits Work
- How Electricity Works
- How Solar Cells Work
- How Fuel Cells Work
- Could blood be used to power batteries?
- Can my laptop battery be overcharged?
- How do the battery testers on battery packages work?
- Why do batteries seem to go dead and then come back to life if you let them rest?
- What are all the different ways to store energy besides using rechargeable batteries?
More Great Links
- BBC: How Do Batteries Work?
- The Official Lemon-Power Website (It's about using lemons to power stuff!)
- Deep Cycle Battery FAQ
- Georgia Tech Center for Fuel Cell and Battery Technologies
- American Chemical Society. "History of the Battery." National Historic Chemical Landmarks. 2005. (June 23, 2011) http://acswebcontent.acs.org/landmarks/drycell/history.html
- "Batteries." Intro to Physical Computing, New York University. April 19, 2011. (June 23, 2011) http://itp.nyu.edu/physcomp/Notes/Batteries
- Brand, Mike, Shannon Neaves, and Emily Smith. "Museum of Electricity and Magnetism." National High Magnetic Field Laboratory. 2011. (June 25, 2011) http://www.magnet.fsu.edu/education/tutorials/museum/index.html
- Buckle, Kenneth. "How Do Batteries Store and Discharge Electricity?" Scientific American. May 29, 2006. (June 23, 2011) http://www.scientificamerican.com/article.cfm?id=how-do-batteries-store-an
- CalRecycle. "Rechargeable Batteries and Chargers: A Personal Perspective." Sept. 9, 2009. (June 25, 2011) http://www.calrecycle.ca.gov/ReduceWaste/power/rechbattinfo.htm
- California Energy Commission. "Lemon Power." 2006. (June 22, 2011) http://www.energyquest.ca.gov/projects/lemon.html
- Coyne, Kristen Eliza. "Interactive Tutorials." National High Magnetic Field Laboratory. 2011. (June 23, 2011) http://www.magnet.fsu.edu/education/tutorials/java/index.html
- Davidson, Michael W. "Electricity and Magnetism: Batteries." Jan. 28, 2003. (June 22, 2011) http://micro.magnet.fsu.edu/electromag/electricity/batteries/index.html
- Decker, Franco. "Volta and the 'Pile.'" Electrochemistry Encyclopedia. January 2005. (June 23, 2011) http://electrochem.cwru.edu/encycl/art-v01-volta.htm
- Duracell. "Power Education." 2010. (June 23, 2011) http://www.duracell.com.au/en-AU/power-education/index.jspx
- Energizer. "Learning Center." 2011. (June 22, 2011) http://www.energizer.com/learning-center/Pages/facts-history-care.aspx
- Environmental Protection Agency. "Batteries." Dec. 1, 2010. (June 22, 2011) http://www.epa.gov/osw/conserve/materials/battery.htm
- Frood, Arran. "Riddle of 'Baghdad's Batteries.'" BBC News. Feb. 27, 2003. (June 23, 2011) http://news.bbc.co.uk/2/hi/science/nature/2804257.stm
- GreenBatteries. "Information on Environmentally Friendly Rechargeable Batteries." 2011. (June 25, 2011) http://www.greenbatteries.com/faqs.html
- Idaho Public Television. "Electricity Facts." 2011. (June 25, 2011) http://idahoptv.org/dialogue4kids/season6/electricity/facts.cfm
- Iggulden, Hal. "The Dangerous Book for Boys." New York: HarperCollins Publishers, Inc., 2007.
- Komando, Kim. "Learn How to Maximize Battery Performance." USA Today. Aug. 7, 2005. (June 25, 2011) http://www.usatoday.com/tech/columnist/kimkomando/2005-08-07-battery-life_x.htm
- Manjoo, Farhad. "Better Batteries Will Save the World." Slate. June 21, 2011. (June 23, 2011) http://www.slate.com/id/2297125/
- Rahim, Saqib. "Will Lithium-Air Battery Rescue Electric Car Drivers from 'Range Anxiety?'" The New York Times. May 7, 2010. (June 22, 2011) http://www.nytimes.com/cwire/2010/05/07/07climatewire-will-lithium-air-battery-rescue-electric-car-37498.html?pagewanted=1
- Savage, Neil. "Batteries That Breathe." DiscoveryNews. Feb. 8, 2011. (June 22, 2011) http://news.discovery.com/tech/batteries-that-breathe-110208.html
- University of Hawaii HAM Club. "Batteries in Fact and Fiction." August 1999. (June 22, 2011) http://www.chem.hawaii.edu/uham/bat.html