US retail giant Walmart is suing Tesla over fires it says were caused by solar panels on the roofs of its stores.

Walmart claims the electric vehicle, storage and PV group “engaged in widespread, systemic negligence” over installation and maintenance of its solar systems at stores, say papers lodged with the New York State Supreme Court.

Walmart, which has 244 rooftop solar contracts with Tesla, sent in experts to investigate after a series of fires at its sites in 2018.

The court papers claim the problems stem from “chaotic installation practices” adopted by SolarCity, the US PV group that Tesla bought in 2016 and which the latter failed to correct, according to Walmart.

Tesla has not yet commented on the lawsuit, which seeks to force it to remove the PV installations from Walmart’s rooftops.

The legal action comes days after a relaunch by Tesla CEO Elon Musk of the Tesla Solar business, which has seen installations decline this year.

Tesla Solar hopes offering homeowners the chance to rent what Musk called “a money printer on your roof” will revive its fortunes.