Designing DC Coupled Off-grid Solar System

Hello all

I have sizing an off-grid solar system to power a house appliances and it would be greet if solar systems experts check my design and leave their valuable notes.
I will appreciate your comments and notes.

Thank you.

Using 20kwh at night, it beats me why you are only considering one battery.
I would have thought 20~30kw battery would be more suitable to obtain a long term savings.

Look at the solar trackers on here, apparently 8 panels will harvest 35kwh per sunny day.

Lithium-ion batteries price is high as you may know, so I try to reduce the battery bank capacity.
20KWh at night is the worst scenario.
Yes we have panels that will produce about 35kwh per day witch some of that energy will be wasted but it’s possible that during the day time the owner my run all devices so the battery bank will be charged two times in one single day.

I am sure cycling most batteries twice a day, will/may greatly shorten the lifespan of your batteries.

We purchased 10.24kwh lifepo4 battery for 5'150 from www.powergrids.com.au when the AU was lower than it is now.
An off-grid mate west of Mackay QLD, just ordered three 10kw batteries for some $11’700 I recall that included delivery.
Each battery is 110kg crated, so two people needed to carry them.
Good luck with your project.