Boat backup

[manchester2]

Boat in marina has shore AC to keep engine heater on in cold weather . I seek a backup device where device is normally connected to shore ac and runs the ac heater and charges batteries. If shore ac fails then device auto switches to battery and solar to run the ac heater. When shore ac returns, device switches back to shore ac and recharge the batteries

Do I need a :
Hybrid inverter charger ?
Solar power station ?
Something else ?

I can't see the difference except that the power station has battery inside and hybrid inverter charger has external battery.

Am I correct or am I missing something here

Much appreciated

 

[chrisski]

What is the total kWh requirement per day?

I guess the charging of batteries is not much but a heater powered on solar could be expensive.

 

[wme]

What type is the heater. Restive or a heat pump.

 

[mikefitz]

device switches back to shore ac and recharge the batteries

Does not sound practical unless the heater is very low power. Perhaps solar would be a solution.
What heater power and expected duration of loss of shore power?

 

[740GLE]

So the engine (coolant or oil) is heated 24/7?

Sounds luxurious!