This is when Android starts to drain all the juice from the battery, as it will start searching for a wireless connection, and this process requires a lot of energy, it will continue until we manually turn off the Wireless connection, or we find a hotspot.
This is where Wifi Battery Saver Widget comes to save the day!!! Once activated, it will scan for active wireless connections, if it finds that the Android device have the Wifi turned ON, but is not connected to any Wireless network, it will just turn OFF the Wifi connection! That simple!! NO ROOT ACCESS REQUIRED!!!
Once you put the Widget in the homescreen, just tap it once to activate it, and tap it again to deactivate it. :)