To charge a fully discharged battery, you need to follow these steps: Connect the battery to the charger: Make sure the charger is appropriate for the battery and connect the battery to the charger. Turn on the charger: If the charger has a power button, turn it on. If the charger doesn't have a power button, plug it into an electrical outlet. Monitor the battery's charging progress: Some chargers have indicators that show how much the battery has charged, while others simply turn off when the battery is fully charged. Disconnect the battery from the charger: Once the battery is fully charged, unplug it from the charger. Avoid overcharging the battery, as this can reduce its overall lifespan. Note: The charging time for a fully discharged battery can vary depending on the battery's size, type, and charging rate, but most batteries take several hours to charge fully.