You might use ~13 diodes in series (.7v drop each) to reduce the battery voltage to a point where it can be input to an arduino analog input pin. There are a number of ways to display the arduino analog pin values in a web page.
You might use ~13 diodes in series (.7v drop each) to reduce the battery voltage to a point where it can be input to an arduino analog input pin. There are a number of ways to display the arduino analog pin values in a web page.