FreeWire Technologies went to market with a rolling battery that charges cars. After a recently closed $15 million Series A, the Bay Area startup plans to tackle a bigger challenge.

Electric vehicle range gets better with each new model, but charging time remains an impediment to mass adoption. At the same time, the power flows needed for faster charging create a stress on the local distribution grid, adding cost and time to the process of charger deployment.

FreeWire’s next product will be an “infrastructure-light” charger that uses lithium-ion batteries to minimize stress on the grid, said CEO Arcady Sosinov. That vision won over BP Ventures, which led the round, joined by Volvo Cars Tech Fund, Stanley Ventures, Blue Bear Capital, Oski Clean Energy Partners and others. Macquarie Capital Venture Studio contributed a separate $1 million last week.