BATTERIES
As many small-scale methods of electricity generation are available only intermittently, some form of electricity storage, or battery, is needed if people want to have electricity available at all times.
Overview of Battery Types[edit | edit source]
There are a wide range of batteries available. This Technical Brief aims to introduce the advantages and disadvantages of different types of batteries. The central point is that there is no such thing as a universal battery; a single type of battery cannot cover all applications.
Detailed Description[edit | edit source]
You can find a more in-depth description of how batteries work, the terms and definitions used to specify rechargeable batteries, and details about charging battery systems in Chapter 7 of Rural Lighting, published by ITDG Publishing.
Classification of Batteries[edit | edit source]
Batteries can be sub-divided into the following types:
- Primary Cells or Dry Batteries
Standard zinc-carbon Alkaline or heavy duty
- Secondary Cells or Rechargeable Batteries
Lead-acid battery:
- Vented lead-acid
- Automotive (car)
- Deep-discharge or traction
- Stationary
- Low-antimony solar battery
- Sealed or valve-regulated
Nickel-Cadmium batteries:
- Vented
- Sealed
Common Applications[edit | edit source]
The familiar flashlight battery is perhaps the most commonly used battery, particularly in the South. This type of battery comes in standard sizes of AAA, AA, C, and D. Although the purchase or first cost of dry cells is relatively low, it is one of the least cost-effective electrical power sources in terms of the cost per unit of useful energy delivered. Furthermore, only a limited energy yield can be obtained before the battery has to be thrown away. Dry batteries are used in especially large numbers by the poor, as they are convenient, just about affordable, and generally all that is available. Their high cost makes them only suitable for powering small appliances that can only be used economically for short periods or emergencies.
Battery Configurations[edit | edit source]
- Series Connection
If cells or batteries are connected + to -, so that their voltage adds up to the required value for the application, they are said to be series connected.
- Parallel Connection
If two or more cells or batteries are connected + to + and - to -, then they are said to be parallel connected.
Technical Definitions[edit | edit source]
A packaged combination of cells is technically known as a battery. In most cases, a number of cells packaged in a single container or sleeve, typically three or six 2V lead-acid cells to give a 6 or 12V battery.
Environmental and Safety Considerations[edit | edit source]
Primary cells are stable in terms of self-discharge. Some of the alkaline 'heavy duty' types can be kept for several years with no more than a few percent loss of capacity. Care is needed as, apart from the battery acid being extremely corrosive, hydrogen gas is produced, which is highly flammable and potentially explosive when mixed with air. Thus care should also be taken to avoid naked flames or sparks in the battery enclosure, especially if the battery is housed in a confined space. Never check the electrolyte levels with a naked flame such as a kerosene lamp or a candle. For the same reason, battery storage areas should be well ventilated.
References and Further Reading[edit | edit source]
For more information about Appropriate Technology contact: Research Information Ltd., 222 Maylands Avenue, Hemel Hempstead, Herts, HP2 7TD, United Kingdom. Tel: +44 (0)20 8328 2470, Fax: +44 (0)1442 259395, E-mail: info@researchinformation.co.uk, Website: www.researchinformation.co.uk
