How can you fix a 1800w inverter for your car and will you need another battery and also what breaker will you use?

If you dont understand the how to wire things into a dc system such as "do i need another battery", don't attempt to install this, there is very little reason you could need 1800 watts AC in a car anyway

There is a world of difference between putting batteries in series or parallel (not going to explain this here) and if you chose the wrong option, not only can you get hurt, but say goodbye to all the electronics in your vehicle to include the ECM, Stereo, etc.