Measuring forklift battery's voltage
It seems you want to measure a voltage that can be from 7 to 30 volts with a A/D converter with a full scale range of 0 to 1.2 V.  What you need is a "voltage divider".  This is just two resistors in the simplest case:



In this case, 30 V needs to be scaled down to 1.2 V, which is a factor of 25.  That means R1 needs to be 24 times R2.  For example, R2 could be 10 k&Omega; and R1 240 k&Omega;.  That is exactly on mathematically, which doesn't leave room for tolerance of the parts.  It would be best to make R1 a little higher, like the next higher up standard value 270 k&Omega;.  In that case the divider will divide by (R1 + R2)/R2 = 28, so the input voltage range the A/D can measure will be 0 to 33.6 V.

That's the basic answer to the question you asked, but a few things seem strange.  Are you really sure the A/D range is only 1.2 V?  That is possible, but surprisingly low.  Also, 7-30 V sounds like a very large range for a battery.  That implies the battery can be drained down to less than 1/4 of its maximum charging voltage, which is very low and can damage most types of batteries.  What kind of battery do you have?  Where did you get the 7 and 30 volt figures from?