Last year Tesla announced a revolutionary breakthrough in home battery systems called the Powerwall. The Powerwall is a stand-alone Lithium-Ion battery designed to power your house.

They announced a 7kWh and 10kWh version of their Powerwall slated to come to market this year (for reference, the average US home uses 30kWh/day). But just a few weeks ago Tesla quietly removed the 10kWh model from their website and press kit. A Tesla spokesman confirmed the removal by saying,

“We have seen enormous interest in the Daily Powerwall worldwide,” according to an emailed statement to GTM. “The Daily Powerwall supports daily use applications like solar self-consumption plus backup power applications, and can offer backup simply by modifying the way it is installed in a home. Due to the interest, we have decided to focus entirely on building and deploying the 7-kilowatt-hour Daily Powerwall at this time.”

The reason behind the drop had to do with the economics of the Lithium-Ion battery. While the 7kWh is marketed as a daily-use battery, the 10kWh was intended to act as more of an emergency backup solution. The problem is that traditional lead-acid batteries have twice the battery life, and cost half as much. For that reason the 10kWh just didn’t make sense in the lineup.

However, Tesla continues to focus on the Powerwall product line. In January, Tesla CEO, Elon Musk said,

“We’ve got the Tesla Powerwall and Powerpack, which we have a lot of trials underway right now around the world. We’ve seen very good results,” said Musk during a talk to Tesla car owners in Paris, The Verge reports. “We’ll be coming out with version two of the Powerwall probably around July, August this year, which will see further step-change in capabilities.”

So it appears that Tesla will continue to innovate the Lithium-Ion battery market, they’ll just do so without the 10kWh model for the foreseeable future.

Read more about why Tesla dropped the 10kWh LI battery.