Originally Posted by waterjosh
Having an auto transfer EMS system is a great idea. It could be simple. It could be a little complicated. Usually they are used with bigger inverters and bigger battery banks.
You could use the 1500 watt inverter as you proposed. Previous posts have pointed out there may be many manual steps to switch over.
I have the 1000 watt version of that inverter. The 1500 watt version is a little more powerful of course. Mine severely taxes a 200 amp hour AGM battery bank when running a hair dryer on low setting. You would need 300 or 400 amp hours of deep draw batteries to use the full capability of the 1500 watt inverter.
Since my inverter is so limited, I installed dedicated 120 volt wiring keeping it separated from shore power wiring. The inverter provides circuit breaker protection. I can easily control what uses the 1000 watt inverter. I use the inverter for a massage vibrator and power bricks for computers. No microwave, hair dryer, or coffee pot.
The 1500 watt is a bit more powerful. It may run a microwave or coffee pot. You could use a second 120 volt sub panel and connect a limited set of existing circuits to the sub panel. Connect the sub panel to a transfer switch. It will switch the sub panel between house 120 volts and the inverter.
I would do the following for myself if I were doing it:
Connect the microwave outlet and one string of wall outlets to the new sub panel.
Add a new 30 amp branch breaker in the old main panel in place of a now disconnected circuit.
Use 10 gauge wire to the transfer switch.
Use 10 gauge wire from transfer switch to new sub panel.
Use 14 gauge wire from transfer switch to the inverter. The inverter will trip at around 12 amps so 14 gauge is OK.
Don't include the converter/charger as one of the inverter sub panel circuits.
Don't include water heater, refrig or other circuits in the inverter sub panel.
This way you are switching only one or two 15 amp circuits, not the whole 30 amp shore power system.
My advice is worth what you pay for it.
I wish you good luck and happy trails ahead.