15 solar panels might produce 5,000 watts on a sunny day .So If...

15 solar panels might produce 5,000 watts on a sunny day .
So If half of the above days are sunny you would be topping up your ATC container with 250,000 watts. (Aussie might get 60% sunny days)
So that will fill your your one million watt container by 25%.
I'm not too smart but I guess that One container would last you about 1/2 the winter in an efficient enough house with 15 solar panels cranking on 50% sunny days.
Saving you about $500
I guess if you live in a warmer climate the one container should last you all year long, But not really get you off the grid (with your 15 solar panels on your roof)
If you have a cheaper off peak power source there would be no problem topping up so it could be a great option there!
So if you are saving $1000 to $1500 per year you would need to calculate the the number of years to payback based on what the prices of the product will be / and the price of your solar panel installation would cost. (carbon credits obtained also)

I'm not sure about other battery product comparisons.
DYOR