The Tesla Powerwall's come in 2 different configurations. At launch in Australia, just the 7kW is available. However, the great advantage in using this system is its the way in which it can be scaled up. If you want more capacity to such up the spare solar power you have, just add another Powerwall with its 3.3kW continuous output capability, it can power most domestic air-conditioning units for at least an hour full throttle.
The next size up 10kW unit is aimed also at the off-grid market. Although it is unlikely to be large enough to run a modern creature comfort home it may just do the job in an energy efficient home.
Which one to choose? Answer: Wait.
The good news is that all the hybrid ready inverters are connected to the internet and log the solar system's energy generation. When we come back and compare your export to your generation we can, with much greater precision, size your hybrid solar system battery component. You might find you need one Tesla Powerwall compared to the 2 your though you might need and with just a little patience, you have saved yourself a whole lot of money!