i used a 12v adapter (standard one) for arduino uno. then i connected a relay with it (5V relay). In that relay, the desired voltage pin is connected to a separate 12v battery (finely working). Output pin(with desired signal when the relay gets signal from arduino) is connected to solenoid valve which gets actuated (make way for water to pass thru) when it receives 12v signal .
so total current consumption is less than 1A against 1~1.5 A which is supplied to arduino.
Current Consumption isnt important here!!! I already said that i tested this timer with onboard LED instead of relay and solenoid stuff and still got the problem.. So the problem is totally with the code and not with the current supply... please do understand that...thanks