Circuit schematic for battery charge controller.

[Siddhat]

Hello,
Can anyone help me with the circuit diagram to make a 12V lead acid battery charger?What I need is it should cut off the the power  when the battery attains fully charged voltage(which is the upper threshhold voltage)and it should also auto recharge the battery when the battery reaches a certain lower threshhold voltage.But the charging should not be done between the upper threshhold and the lower threshhold.
i am planning to use a schmitt trigger as shown below but I cannot make a proper circuit diagram.
I have searched the internet and tried on a bread board but none of the circuits seem to work.
I have my presentation tomorrow and I dont have a circuit that works.So can somebody make a circuit diagram for the above explained works.
Appreciate your help