3kw inverter in a Diesel

Ive been wanting to put an inverter in my truck to run a 3/4 hp electric pump. I will need a 2.5-3kw inverter.

Thats a pretty big one. I figured i would need 2 batteries and being a diesel my truck already has 2 batteries. How would I wire this properly. I already have an alternator to support it at 250 amp w/ 160amp at idle.

Run cable from the main battery to a fuse block. Then run cable from the fuse block to a battery isolation relay. Hook one wire of the control terminal on the relay to a switched "hot" on your ignition switch and the second wire to ground. Then run a cable from the isolation relay to another fuse block. Cable from the fuse block to a Valve regulated sealed AGM type battery located right next to the inverter. Then add a third fuse block between that battery and the inverter.

See a complete article on this site: http://www.ricksfreeautorepairadvice.com/repair-topics/electrical/generate-ac-power-from-your-car-or-truck