Installing more rooftop solar is a better investment than a Powerwall 2, so always rack up as much solar on your roof as you reasonably can first. Unlike this guy.

The Tesla Powerwall 2 is going to be big.  Really big.  I mean that literally and not figuratively.  It’s going to be big as in 13.5 kilowatt-hours of storage big.  From the point of view of most Australian households that is huge.

This large capacity presents households with two main problems:

1.  It is more than the average Australian household uses at night.
2. Those that do use that much electricity overnight may not have a rooftop solar system large enough to fully charge it.

So if the average Australian home buys a Powerwall 2 they will use it at less than its full capacity. As Tesla’s warranty is fixed at a maximum of 10 years, this increases the cost of each warranted kilowatt-hour substantially.

The obvious solutions are:

1. Don’t install a Powerwall 2 unless your household regularly uses 12+ kilowatt-hours of electricity overnight.
2. Don’t install a Powerwall 2 unless your solar system normally produces enough surplus electricity to fully charge it on a mostly clear day.  Normally this will require at least 5 kilowatts of solar panels.

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