German energy storage company Sonnen has officially opened its new headquarters in Los Angeles, and is wasting no time in selling batteries to as many American customers as possible.

Sonnen announced today that it is teaming up with SolarWorld, the largest crystalline-silicon solar manufacturer in the U.S., and PetersenDean, a large California-based roofing and solar company, to offer a complete solar-plus-storage package for the U.S. residential market.

Partnerships are a key element of Sonnen’s expansion plans as it tries to edge out Tesla, its top competitor. The German energy storage company has already built a U.S. distribution network of more than 30 local solar installation companies, and plans to grow that network to 100 dealers by the end of the year.

Sonnen also announced today that it’s working with Spruce, the product of a recent merger between Clean Power Finance and Kilowatt Financial, to develop a financing product focused purely on energy storage.

The two companies plan to make financing available to Sonnen’s channel partners in the first quarter of 2016. They’re also working on a solar-plus-storage financing option for release later this year.

“We’re building a comprehensive product that allows our channel partners to provide their end customers with a solution that’s fully integrated in all aspects,” said Boris von Bormann, CEO of Sonnen North America, in an interview.

The battery system itself is an integrated solution that incorporates a Sony Fortelion lithium-iron phosphate battery, an inverter, and a control system that can be accessed via computer or smart phone, or through a user interface on the battery.

Sonnen offers a commercial battery product, but its core market is on the residential side. Today, the value proposition for residential storage is largely for resiliency, like in the Northeast, where customers have to cope with severe winter storms, and for self-consumption, typically in places with high electricity costs, like Hawaii. New mandatory time-of-use rates in California will also make residential storage more attractive as a way to arbitrage between peak and off-peak times.

Sonnen told Greentech Media in mid-December that it had shipped the first 1,000 U.S. storage system orders from its factory in San Jose, and expected some of those systems online before Christmas.

Tesla, meanwhile, confirmed it has started manufacturing its Powerwall batteries at the Gigafactory in Nevada, and is expected to make the first deliveries in Australia next month and soon begin making deliveries in North America. However, it's unclear when the systems will actually be installed.

A pricing comparison finds the Powerwall is likely cheaper than Sonnen's offering, but prices vary based on product type and location. Both firms would appear to be engaging in specsmanship in their claims, as well.

In the U.S., von Bormann said Sonnen’s recent deliveries give the company first-mover advantage. 

“The important point is not just that we’re first; it’s that we’re first in the market with a product that’s been tested in thousands of units in various markets around the world,” he said.

Sonnen is currently the leading battery system vendor in Europe. And in the coming weeks, the company will hit 10,000 battery sales worldwide. Since residential batteries live in the home, sometimes right next to where people sleep, there's a high value placed on a proven safety record, said von Bormann.

Sonnen’s partnership network could also give the German company a leg up in the U.S. over Tesla, which plans to work primarily through its partner SolarCity.

“There aren't many markets with an economic proposition for the residential segment, as a result of which we haven't seen many financing products catering to the residential segment,” said Ravi Manghani, senior energy storage analyst at GTM Research. “Residential storage vendors will have to rely on strong channel partners, and not financing packages alone to acquire customers. Sonnen's partnerships with SolarWorld and PetersenDean offer it such channels.”

PetersenDean is one of the largest roofing companies in the country, and the eighth-largest residential solar installer in the country, according to GTM Research's U.S. PV Leaderboard. By manufacturing in the U.S., Sonnen aligns itself with PetersenDean’s “Made in America” campaign.

“They’re right in our swim lane,” said Erin Clark, president of PetersenDean’s solar division, in a statement. “We are all resolved to offer complete solar solutions that include and promote the arrival of storage. We, SolarWorld and Sonnen are all best-in-class operators and employers right here on U.S. soil.”  

The grand opening of Sonnen’s new headquarters in L.A. today cements the company’s presence in America, building on the launch of its manufacturing plant in San Jose, and its research and development hub in Atlanta. With a major launch event planned for tonight, the company intends to make its presence known. The next step is translating that presence into sales.