The transformer is 220V to 12V step down (12-0-12) 4 Amp transformer. And the battery is 12V 7 Ah Lead Acid battery.
First of all - the circuit doesn't work on Simulator. However, I found several blogs claiming that the circuit is valid and works. Could you please let me know why it doesn't work on simulators? And secondly, are the values of R1 - R4 correct in order to allow 2N3055 to oscillate? I am planning to use all the 4 resistances 10Watt rated.