Electric-vehicle charging stations are becoming more powerful in order to serve the next generation of plug-in cars, outfitted with bigger batteries that allow them to travel longer distances. Widespread availability of affordable, long-range EVs, coupled with convenient charging options, is considered essential if these vehicles are to reach mainstream consumers.

The problem is that high-powered fast chargers put a strain on the electric grid, which can be difficult for a utility to manage and hit EV customers with high rates.

Enter the Bay Area startup FreeWire Technologies.

FreeWire offers mobile distributed energy systems that are roughly the size of a washing machine and packed with second-life EV batteries. The benefit of using second-life batteries is that they’re more affordable than new ones, while still high-performing. Lithium-ion battery costs have dropped precipitously in recent years, but CEO Arcady Sosinov maintains that the used EV batteries in FreeWire’s Mobi systems are still six times cheaper.