The only real time experience I did once was with a 1500 PSW INVERTER running about 1400WATTS of HP Test Equipment on a field trip once. We hoked it up to the renatl car battery which was probably about 105AH capacity.
The Test equipment ran for about 8 minutes before discharging the battery. We also had the rental car running at the time and it all went dead.
Called the rental car company and they brought a different rental car for us. We went to town and purchased a 2KW Honda generator...
Told the rental car company we had no idea what happened to their car haha...
With this true story in mind I suspect your 250AH battery bank capacity you will see maybe 45 minutes total run time once you change out your 30AMP fuse to a 150AMP fuse. Just a guess on my part...
You will most likely have to order your fuse and holder from a company called BLUE SEA to get a FUSE ASSY that will work with 4AWG cables and ring terminals.... This can be ordered through AMAZON as well just type in the right part number.

Roy Ken