Here is a schematic 300W power inverter with 12 volt batteries as a source. This inverter is controlled by 555 timer and CD4017 decade counter. You should try to build this inverter, because it can be used to power load 300W. With the power was sufficient to illuminate a few light bulbs at night for your camping needs.
This 300W power inverter is quite simple but powerful, efficient, and stable. The inverter is built using a 10V center tap transformer. A 555 Timer IC and a 4017 decade counter IC used to produce a modified sine wave of 50 Hz.
Timer 555 will produce a frequency of 200 Hz (see the schematic for more info) by adjusting the potentiometer value of 500K. CD4017 produces the pulse trains on pin 2 and pin 7 of CD4017 is connected to the gates of the MOSFET STP36NF06L. It then directed to the transformer primary side. There will be 220V AC at the transformer secondary side.
In order for the inverter system can run to efficiently use the cooling fan, even though the heatsink is still needed.