BMW's new rechargeable home battery could rival Tesla's Powerwall

BMW is making a line of at-home batteries that could rival Tesla's Powerwall if it pans out the way the company says it will.

Many home owners are buying at-home batteries so they can store energy collected from solar panels and use it at night or when utility rates are high. It's also a more convenient way to charge an electric car if you have one.

The most commonly known option is Tesla's Powerwall, a $3,000 lithium battery that offers 6.4 kWh of capacity. For reference, the average person in the US uses about 30 kWh of power a day.

But BMW is planning to offer two at-home battery options with far better capacity at 22 kWh or 33 kWh.

"You could power your home for a day, for 24 hours," Cliff Fietzek, manager of Connected eMobility at BMW, told Tech Insider.

That's a pretty major step up from other battery options on the market, as well. Sunverge offers an at-home battery with 23 kWh of capacity and ElectrIQ will offer one with 10 kWh of capacity at the end of 2016. Other automakers in the field, like Mercedes and Nissan, only offer 2.5 kWh and 4.2 kWh of capacity, respectively.

Since Tesla's Powerwall is modular, you can opt to stack nine batteries for 57.6 kWh of capacity. Doing so will cost $27,000, not factoring the price of installation, though.

BMW also plans on having a competitive edge by cutting down on the cost of installation.

The automaker will resuse the batteries in its BMW i3 for home energy storage. Reusing batteries instead of making entirely new ones means BMW doesn't have to build any kind of air conditioning unit for its system, cutting down on the cost of installation.

"One of the unique selling points of our system is we are literally taking the battery out of the car and unplugging it," Robert Healy, manager of BMW's electric vehicle infrastructure, told Tech Insider. "Our system is a plug-and-play ststem. We are the only OEM that can do that."

BMW declined to provide any kind of estimate for how much its at-home battery option will cost. That's a pretty key piece of information, since a really high cost may turn off homeowners even if it does have better energy capacity.

It's not clear when BMW's at-home battery will hit the market, but the automaker will launch a pilot program to test it soon, most likely in California, Healy said. BMW is partnering with Solar City to eventually sell its batteries, rather than appealing directly to customers.

"It doesnt make sense to scrap the battery at the end of the useful life of the car because it's still good for services like powering your home," Fietzek said. "The car battery may be over designed for a home storage system, but well suited."