A device for converting chemical energy into electrical energy. A group of voltaic cells connected in series.

Bichromate2 voltsDry cell1.5 volts
Bunsen1.9 voltsNickel Cadmium1.3 volts
Daniell1.08 voltsNickel Iron1.4 volts
Grove1.8 voltsZinc-silver oxide1.8 volts
Leclanche1.46 voltsClark cell1.4333 volts (absolute)
Weston cell1.0186 volts (absolute)

Standard Cell Voltage: The reversible voltage of an electrochemical cell with all active materials in their standard states.

Note: Weston and Clark cells are standard cells used as references, all others are approximate EMF's.

The main parameters considered when selecting batteries:
  1. ampere-hour capacity
  2. cost
  3. depth of discharge
  4. lifetime
  5. rechargeability
  6. ruggedness
  7. temperature environments
  8. weight


Permanent loss of capacity as a result of battery use and/or the passage of time.


In a discharging battery the anode is the negative terminal since that is where the current flows into the device. This inward current is carried externally by electrons moving outwards, negative charge moving one way constituting positive current flowing the other way. It is continued internally by positive ions flowing into the electrolyte from the anode.


The ability of a fully charged battery to deliver a specified quantity of electricity (AH) at a given rate (amps) over a definite period of time (hours).


In a discharging battery or a galvanic cell the cathode is the positive terminal since that is where the current flows out of the device.

Cell Reversal

Inversion of the polarity of the electrodes of the weakest cells in a battery, usually as a result of overdischarge.

Charge Acceptance

The ability of a battery to convert active material during charge into a form which can be subsequently discharged.

Coulombic Efficiency

For a rechargeable battery the fraction of the electrical charge stored during charging that is recoverable during discharge.

Cut Off Voltage

The selected voltage at which charge or discharge is terminated.

Cycle Depth

Fully discharging a battery often destroys the battery or, at a minimum, dramatically shortens its life. Deep-cycle lead-acid batteries can be routinely discharged down to 15-20% of its capacity - this represents a depth of discharge (DOD) of 85 to 80%.

Float Life

The number of years that a battery can keep its stated capacity when it is kept at float charge.

Float Voltage

The voltage at which the battery is floated, or just enough current is supplied to equal the self-discharge of the battery.

Local Action

A continuation of current flow within a battery cell when there is no external load.

Self Discharge

The loss of useful capacity of a cell or battery due to internal chemical action.

Shelf Life

The period over which a battery can be stored and still meet specified performance criteria.

Short Circuit

The direct connection of positive and negative electrodes either internal or external to the battery.

State of Charge

The charge state of a battery is often simplistically estimated from voltage. However, this can give errors as the voltage will change depending on the current demand, prior use, age, temperature etc. More sophisticated battery state monitors use temperature, impedance and history of use.


The external connection to a battery electrode.

Historical Notes

  1. 1800 Alessandro Volta develops the electric battery.
  2. 1839 Fuel Cell invented by William Grove.
  3. 1901 Thomas Edison invents the Nickel Iron battery.
  4. 1932 First successful fuel cell produced by Francis Bacon.

See also: Absorbed Glass Mat Battery, Accumulator, Alkaline Battery, Aqueous Battery, Batteries in Parallel, Battery Bank, Battery Capacity, Battery Cell Balancing, Battery Charger, Battery Conditioning, Battery Cycle Life, Battery Efficiency, Battery Holder, Battery Module, Battery Pack, Battery Rupture, Battery Separator, Battery String, Battery Testing, Battery Venting, Bipolar Battery, Button Cell, Carbon Zinc Battery, Cell Voltage, Charge Acceptance, Clark Cell, Coin Cell, Concentration Cell, Coulombic Efficiency, C Rate, Cylindrical Battery, Depth of Discharge, Dry Battery, Electrochemical Cell, Electrochemical Energy Storage, Electrochemistry, Electrolyte, Energy Density, Energy Storage, Flow Battery, Flywheel Battery, Fuel Cell, Galvanic Cell, Iron Air Battery, Lead Acid Battery, Leclanché Cell, Lithium Ion Battery, Lithium Iron Sulphide Battery, Lithium Polymer Battery, Nickel Cadmium Battery, Nickel Iron Battery, Nickel Metal Hydride Battery, Nickel Zinc Battery, Nominal System Voltage, Open Circuit Voltage, Pouch Cell Battery, Power Density, Primary Cell, Prismatic Battery, Ragone Plot, Rechargeable Battery, Secondary Cell, Self Discharge, Silver Oxide Battery, Silver Zinc Battery, Sodium Nickel Chloride Battery, Sodium Sulphur Battery, Standard Cell, Standard Electrode Potential, State of Charge, Traction Battery, Voltaic Efficiency, Voltaic Pile, Watt Hours per Kilogram, Weston Cell, Zinc Air Battery, Zinc Bromide Battery, Zinc Chloride Battery.

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Subjects: Electrochemistry Electronics Physics

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