In 2015, Tesla unveiled the Powerwall — a rechargeable lithium ion battery weighing roughly 200 pounds that you can mount on your wall. Panasonic makes the cells for the Powerwall, while Tesla builds the battery module and pack.
When it was released, there were two versions of the Powerwall: a 6.4 kilowatt-hour model that cost $3,000 and a 10 kWh option priced at $3,500. To help put that into perspective, the average person in the US uses about 30 kWh of power a day.
The Powerwall can store electricity generated by solar panels and draw electricity from the utility grid when rates are low to store for later use. It also provides homeowners with backup power in the event of an outage. All Powerwall installations must done by a trained electrician.
The Powerwall is also modular, so you can install up to nine batteries side by side to store more power. When it was introduced, Tesla received 38,000 preorders for the Powerwall, selling out through the first half of 2016.
Tesla had already made several changes to its battery since its initial release. In March, Tesla discontinued its 10 kWh battery option, making its 6.4 kWh battery its only option.
"Due to the interest, we have decided to focus entirely on building and deploying the 7 kWh Daily Powerwall at this time," a Tesla spokesperson told Greentech Media at the time.
Tesla then said it would introduce a new version of the Powerwall over the summer, but instead released small improvements that made it easier to install and be compatible with a new inverter. The first version of Tesla's Powerwall didn't come with an inverter, requiring homeowners to purchase one separately.
The inverter converts the electricity generated from the solar panels to an alternating current that can be used for power.