Portable solar generators are so useful that you increasingly see them at the beach, campground, job site, or anywhere without access to grid power. But they’re also an expensive luxury if shoved into storage as soon as you return home.

EcoFlow’s $200-ish PowerStream box can help maximize the year-round usefulness of the company’s own solar generators. It’s pitched as a plug-in “balcony solar system” that anyone can install, even if you’re renting an apartment.

These DIY systems…