Mary Barra and Elon Musk may be intense business rivals, but they sounded like old pals as they chatted on Twitter this month about a deal that could help remove one of the biggest barriers to electric vehicle ownership: not enough chargers.Ms. Barra, the chief executive of General Motors, had just agreed to follow Ford Motor in adopting the charging technology developed by Tesla, the carmaker led by Mr. Musk. The deals will allow G.M. and Ford customers to use some of Tesla’s fast chargers. Fear of not finding a charger is a main reason some people hesitate to buy electric cars, surveys show.Ms. Barra gushed about the “fantastic” team at Tesla. Mr. Musk said it was an “honor” to work with her.Beneath the surface of those pleasantries were probably some tough corporate calculations. G.M., Ford and numerous charging companies and equipment suppliers have agreed to work with Tesla because they desperately need the company’s help. In addition to selling more electric cars in the Uni …
