All you need to know about batteries.


There are various types of battery based on different chemistries. To get the best out of them and to avoid problems you need a basic understanding of their advantages and disadvantages, as well as a little about purchasing, maintaining and disposing of them.


  • Old batteries often leak, causing corrosions of the battery contacts, so preventing new batteries from working.
  • Lithium batteries can catch fire and burn violently if over-charged, shorted, punctured, or physically damaged in any way.
  • Button cells must be kept away from small children. If swallowed, this is a medical emergency as death can result in just a few hours, as a result of electrochemical action in the stomach.

How batteries work

(You can skip this section if you like, though a little more knowledge than you actually need is always helpful.)

Non-rechargeable (primary) batteries

Type Advantages Disadvantages Comments
Zinc carbon and zinc chloride
  • Cheap.
  • Available in standard shapes and sizes.
  • Short life and slow death.

Zinc chloride is a heavier duty version of zinc carbon. Alkaline batteries are preferred in almost all applications.

  • Good life at a reasonable cost.
  • Available in standard shapes and sizes, and also as button cells as cheap alternatives to silver and mercury.
This is the most economic general purpose type.
Silver and Mercury
  • Long life
  • Relatively expensive
  • Can only deliver a small current

Normally only available as button cells for watches and calculators.

  • Very long shelf and service lives.
  • Relatively expensive.

Mainly used in smoke alarms and cameras.

Rechargeable (secondary) batteries

Lead Acid

Nickel Cadmium

Nickel Metal Hydride


External links

  • Battery University