I have no experience and don't know where to start. I would like to do a full off grid system.

[Hedges]

My A/C is small (so is house), and mild San Jose weather.
A 15A breaker powers the A/C.
I have about 15kW of panels, 10kW of GT PV inverter, 20kWh of battery (14kW usable).

It is a small battery slapped on a large net metering system.
Panels are mostly aimed at 2:00 PM, added some aimed 4:00 PM. Originally optimized for backfeeding grid back when Noon - 6:00 PM was peak rates, not ideal for off-grid where power all day is useful.

I suggest more PV of multiple orientation, before more battery.

 

[marksrig]

You said...

I am hoping to have at least 100 amps for the garage and run a 200 amp sub panel to the house once it is built. The garage will be where the inverters and batteries are located.

Did you mean you would need a 200A main panel and a 100A sub panel? You can't get 200A from a 100A panel.

My place has a 200A on the main house with a 100A sub panel in the garage where the inverters are. I would just have to run the A/C output of the inverters over to the Main panel to power the garage and the house.