* Battery firm rolls out car chargers to online community
* Solar panel owners can step up power sharing, adding cars
* Looking for partners in car, transmission grid sectors
By Vera Eckert
FRANKFURT, Feb 22 (Reuters) - German solar battery maker sonnen is giving away electric car plugs to new household customers, seeking to attract drivers frustrated by the slow roll-out of shared charging points and link them up to better manage power demand.
The venture capital-backed start-up unveiled its 22 kilowatt sonnenCharger on Thursday for ordering by members of its online energy sharing platform in Germany, with first deliveries expected by the end of June.
Philipp Schroeder, one of its managing directors, told Reuters the company hoped to create a network of electric vehicle (EV) owners to help manage the charging process and minimise disruption for power grids.
"Automotive and power network companies will have to solve these problems anyway and we are hoping for partners," he said.
"There will have to be solutions for mass charging, otherwise the move to EVs will not work," he added.
Worldwide, sonnen has sold 30,000 batteries for storing solar power, mostly to rooftop solar panel owners. Its customers have the capacity to generate a combined 210 megawatts of solar power.
In its core German market, some 80 to 90 percent of customers are signed up to the sonnenCommunity, which shares power production, consumption and storage via data apps.
Customers that opt for a flat tariff get a guaranteed 8,000 kilowatt hours (kWh) of power per year - more than enough for a typical four person household, which uses around 5,000 kWh per year. That potentially leaves them with around 3,000 kWh to charge an EV, equating to a driving range of 15,000-17,000 km.
With the EV plug, customers can choose between slow and fast charging and adjust the required volume, helping to reduce the potential run on power during peak loading times that developers of EV infrastructure say could be a problem.
Sonnen also aims to market unused electricity from community members' panels to the national power grid to help stabilise supply, and to market their battery capacity to absorb wind power whenever grids are unable to transport it to consumers.
"Access to car batteries would give us additional storage capacity," Schroeder said, adding this would cut down on the amount of wind power currently left unused at times of grid bottlenecks.
Sonnen, which sells to foreign markets including Italy, the United States and Australia, saw a 24 million euro increase in turnover last year to around 65 million euros ($80 million), Schroeder said.
$1 = 0.8121 euros Reporting by Vera Eckert; Editing by Mark Potter