The lifespan of a fully charged battery can vary significantly depending on various factors, such as the type of battery, usage pattern, load, and environmental conditions. Here are some general guidelines for the lifespan of different types of batteries:

1. Lead-acid batteries: In the case of lead-acid batteries, which are commonly used in cars, the lifespan can range from 3 to 5 years. However, this can vary depending on maintenance, load, and usage pattern. Regular maintenance, such as checking the electrolyte level and keeping the terminals clean, can extend the battery's lifespan.

2. Lithium-ion batteries: Lithium-ion batteries are widely used in portable electronic devices, electric vehicles, and other applications. These batteries typically have a lifespan of 2 to 3 years, but this can vary depending on usage and battery quality. Deep discharge and exposure to extreme temperatures can negatively affect the lifespan.

3. Nickel-metal hydride (NiMH) and nickel-cadmium (NiCd) batteries: NiMH and NiCd batteries are less commonly used than lead-acid and lithium-ion batteries. These batteries usually have a lifespan of 2 to 5 years, depending on usage and load. The memory effect, which can affect the battery's capacity, can occur in NiCd batteries if they are not charged and discharged properly.

It is important to note that these estimates are averages, and individual batteries can vary significantly. Maintenance and handling of the battery, such as avoiding overcharging or deep discharging, can help extend the lifespan. Also, the battery's performance may gradually decline over time, reducing the total usable capacity.