Greetings all. I have a vertamax 1500 pure sine wave inverter which came with a 150amp in-line fuse on the connection to the battery. My entire house however uses only 21 amps total. Want to know if I change the 150amp fuse to a 30 or 40 amp fuse without causing any damage to the inverter and my system?
It's all in the watts !
12V at 125A = 1500w Add a little bit more for the internal losses, and your inverter needs 140A @ 12VDC to fully power a 120V AC load.
So no need to mess with the fuse. And remember - the cables going to the inverter need to last longer then the fuse, so your cables ought to at least handle 170A or they risk becoming the fuse themselves.