Simple Hack if you ever find yourself missing one battery.
Items Required: Aluminum Foil
This hack works on many items requiring batteries.
In this example I will demonstrate what to do if you have one battery and your flashlight requires at least two batteries.
To replace the 2nd battery you can use aluminum foil rolled up to similar size of actual battery.
Next step is to place the aluminum foil in the flashlight followed by regular battery.
If you did steps above correctly you should be able to use your flashlight with only one battery when 2 batteries are required.