The analog input will have a voltage input and will return a result between 0 and 1023.
So if your input voltage is 1 volt and your reference voltage is 5V, the result of the analog input read
operation would be a number around 200.
If you try reading the voltage of a 1.5V battery, your number in the arduino would be about 300.
Is that what you get when you try measuring the voltage of a battery ?