Hope this makes sense. I have a 110v ac well pump. I have a 2000/4000 watt inverter that should run the pump no problem. I have the solar panels and charge controller wired to 3 deep cycle batteries then to the inverter. The inverter is not automatic so it runs fans and all when switched on. The pump is wired to a pressure switch that starts at 20 psig and shuts off at 40 psig. I do not want the inverter to constantly run so I would like to hook up the inverter either to the pressure switch or to some type of load sensor. The pressure switch has no unused relays so I am unsure how to wire the 12v inverter power switch through it if even possible. I could install another matching pressure switch for the 12v circuit only but may have trouble adjusting them both to match on/off cycles. Is there an easier way to do this. I can easily break the on/off switch circuit to the inverter and wire it through some type of switch. But what type? I know they make automatic inverters but unfortunately I already had this one. Is there a load sensing switch I can install on it?