1-There are 2 relays in the cct. The 1st one is for charging and the 2nd one is for load. When charging v reached to 15.2 then they disconnect the batteries and below 15.2V they charge the batteries. And batteries also provide the voltages to the load in the night and when there voltage goes below 10V they disconnect the load.2- Temperature sensor lm35 reads the temperature of the batteries. For each 1degree rise in temp it shows 10mV. And when the temperature of batteries reaches to 45degree then they disconnect the charging too. (Optional) firstly design the cutoff on the basis of voltage then switch to temperature. Means dt/ DT means it tells the temperature wrt per time.If u cant understand this then just read this plz http://www.mpoweruk.com/chargers.htm#temprise(thanks) 3- Current sensor is used to read the current of batteries. The sensor for this is resistance of 0.1ohm in series. Display the current, voltage and temperature of the LCD. Firstly cutoff the charging and load on the basis of voltages and then temperature too. (Means on both basis but voltage 1 would have highest priority).The current is 0.34A so plz chk that it can easily reads in the ADC .Reference voltage is 5V for all sensors so plz chk that all sensors operate at the same reference voltage or we need different reference voltages.