Nickel-cadmium (Ni-Cd) batteries are a type of rechargeable battery that can be identified by several characteristics.
1. Labeling
- Markings: Most Ni-Cd batteries are labeled with “Ni-Cd” or “Nickel-Cadmium” on the packaging or directly on the battery.
- Voltage: They typically have a nominal voltage of 1.2 volts per cell.
2. Physical Appearance
- Cylindrical Cells: Common sizes include AA, AAA, C, D, and 9V.
- Color: The outer casing of Ni-Cd batteries is often yellow, but can vary depending on the manufacturer. The terminals may also have specific colors or designs.
3. Performance Characteristics
- Memory Effect: Ni-Cd batteries are known for their “memory effect,” which can cause the battery to hold less charge if it is repeatedly recharged before being fully discharged.
- Weight: They are heavier than similar-sized alkaline or lithium batteries.
- Self-Discharge Rate: Ni-Cd batteries have a relatively high self-discharge rate, losing about 10% of their charge per month when not in use.
4. Applications
- Common Uses: Ni-Cd batteries are often used in cordless power tools, emergency lighting, and some types of portable electronics, although they are being phased out in favor of more environmentally friendly options.
5. Recycling Symbols
- Recycling Information: Ni-Cd batteries are marked with a recycling symbol and may include the chemical symbol “Cd” (for cadmium) to indicate that they must be recycled due to the toxic nature of cadmium.
6. Testing
- Voltage Measurement: If you have access to a multimeter, you can measure the voltage. Fully charged Ni-Cd cells will show around 1.2 to 1.4 volts.
- Specific Gravity: Advanced methods like measuring specific gravity of the electrolyte are not common for regular users but can distinguish them from other battery types.
7. Environmental Considerations
- Regulation: Because cadmium is a toxic heavy metal, Ni-Cd batteries are subject to strict regulations for disposal and recycling.
By checking for these characteristics, you can effectively distinguish nickel-cadmium batteries from other types.
