The most common type of rechargeable battery available is the lead-acid cell. These types are used in household electrical appliances as well as cars. A simplified working version can be made in the science lab using acid and lead sheet. This ‘rechargeable battery’ can then be used to investigate how we can charge and discharge these devices.
Equipment required (per set):
- Labpack (4-6V)
- Connecting wires
- Small beaker
- Low voltage bulb in holder (1.5V)
- Crocodile clips
- Thin strips of lead (3x10cm)
- 0.5 mol Sulfuric acid
The equipment should be set up as in Fig 1. The strips of lead can be bent over the edge of the beaker so they remain in position and clipped securely using the crocodile clips.
The ‘cell’ is charged using the labpack for a few minutes. The labpack can then be disconnected from the circuit and the small low voltage lamp clipped in place (see Fig 2). The lamp should light briefly, effectively discharging the ‘cell’
Pupils can investigate the relationship between charging time and the time the lamp remains lit for. The longer the ‘cell’ stays charging, the longer the lamp should remain lit, up to a point.