Tesla is having a party, or so it seems. Tesla Energy has invited media and members of Australia’s “Teslarati” – those with Tesla electric vehicles and battery storage – to an event in Jamestown in South Australia next Friday for a major update on the company’s Big Battery installation.

The media have been given few details, apart from a location, time and date. But the invitation to the “Teslarati” is slightly more forthcoming, welcoming them to a “Powerpack Celebration” on the site of the Hornsdale wind farm, where the big battery is being built.

“You are invited to attend an exciting milestone event as part of the South Australia Tesla Powerpack Project. Join us to celebrate the world’s largest lithium-ion battery project at Neoen Hornsdale Wind Farm.”

Tesla founder and CEO Eon Musk will be in town to appear at the South Australian government’s international space conference being held next week, and so there is strong speculation – as yet unconfirmed – that he will host the Powerpack event.

RenewEconomy suspects the Powerpack celebration will be the formal announcement that a connection agreement has been reached for the project, and when the clock on the “we will build it in 100 days or it’s free” promise starts counting down.

Of course, that deadline is really for marketing purposes only, because the contract with the South Australian government actually calls for the storage to be in place by December 1, in time for the start of summer, and possible heatwaves. There are now 70 days till December 1.

The Tesla Powerpacks – which come in 100kWh units – are already being put in place, but there is still much work to ensure that the configuration is right to deliver the network services required by the government, and the load shifting for the wind farm. (Read this for a full explanation of how the Tesla big battery might work).

But while construction of the South Australia big battery gets into full swing, there are questions about what has happened to the Victoria version of the big battery.

It had held an auction for two different battery storage installations – each of 20MW of power but with a combined total capacity of more than 100MWh. That compares to the Tesla installation in South Australia of 100MW/129MWh.

The results of the auction had been due to be released in late August. This week, the government has been busy getting its VRET (Victoria renewable energy target) through the lower house of parliament, but the talk is that it will be announced soon.

It will need to be, because the government wants them in place by January 1, also to help meet a hot summer, this time without the Hazelwood coal generator.

Which invites more speculation: What if the announcement was timed for Musk to drop into western Victoria on his way to South Australia?

We know Tesla has bid and may well have bid once again with Neoen, the French developers who own Hornsdale, partnered in the South Australia tender and who have won just about every tender they have entered – including for wind, solar and battery storage.

Back in Jamestown, Tesla recently announced that its new Supercharger route in South Australia will soon allow Tesla owners to visit the world’s largest battery site. But they won’t be able to charge at Jamestown just yet, the invited Tesla EV drivers have been told.

Still, there are a bunch of Tesla drivers prepared to make the trip, as we discuss in the latest Solar Insiders podcast. We also discuss how a shortage of Tesla Powerwalls is slowing down the uptake of battery storage in Australian homes. Please click below.

Note: This story has been updated to reflect fact that “Teslarati” includes this with Powerwall battery storage, not just EVs.