Solar installers are struggling to find Tesla Powerwall battery systems

Tesla CEO Elon Musk unveils the Powerwall in April 2015. (Luis Sinco / Los Angeles Times) There’s plenty of demand for Tesla Inc.’s Powerwall home battery systems. The trick is finding installers that have them. Only 12% of U.S. companies that install solar panels and residential batteries carry the Powerwall. Meanwhile, about 55% of customers