How Tesla Megapacks power xAI's Colossus: about $1 billion in batteries since 2024

One of the most concrete business links between Tesla and Elon Musk's AI venture is not software but hardware: big lithium-ion batteries. SpaceX's filings for its stock market listing showed that xAI, now SpaceX's AI division, has bought roughly $1 billion of Tesla Megapacks since 2024 for its Colossus data centres.

The numbers

According to the amended filing reported by Electrek in June 2026, xAI's Megapack purchases from Tesla were:

• 2024: about $191 million
• 2025: about $506 million
• January to March 2026: about $34 million
• April 2026 alone: about $269 million

The filing also showed that Tesla booked about $573 million of revenue from SpaceX and xAI in 2025, roughly 4.5% of its energy business. Separately, SpaceX bought about $131 million worth of Cybertrucks in 2025.

Why an AI supercomputer needs batteries

Colossus, xAI's first data centre in Memphis, Tennessee, was built in about four months and came online in December 2024. Training AI models draws huge amounts of power, and that demand swings sharply within seconds as thousands of chips start and stop work together. Local grids struggle with those spikes. A large battery bank sits between the grid and the computers: it smooths the swings, provides backup power and lets the data centre run while extra grid capacity is still being built. Megapacks are well suited because they come as ready-made units that can be installed quickly.

What it means for Tesla

For Tesla Energy, AI data centres have become one of the fastest-growing customer groups. On its third-quarter call this week, Tesla said demand for Megapacks is strong enough that production for 2027 is close to sold out, with data centres a major driver. xAI is one of the earliest and most visible of those customers.

There is a catch for shareholders: sales to a company controlled by Tesla's own CEO are related-party transactions. They have to be disclosed and should be made on normal market terms. Critics also point out that purchases like SpaceX's Cybertruck order make Tesla's sales figures look stronger than they would with outside customers alone.

The controversy around Colossus

The data centres themselves remain contested. Residents and the NAACP have sued over gas turbines used to power the sites, and in Southaven, Mississippi, a SpaceXAI subsidiary is offering to buy homes near its power plant. Batteries do not solve that problem, since they store power rather than generate it.

What to watch

SpaceX reported 1.7 gigawatts of computing capacity at the end of September and keeps expanding. Every new building is a potential Megapack order, which makes SpaceX's AI plans worth following for anyone interested in Tesla Energy.