The Dark Side of Electric Vehicle Charging

When is the appropriate time to disconnect an electric vehicle from its charger, especially when you really need a charge? Problems have erupted in some parking lots over this issue. While some employers have responded by requiring drivers to book their charging times, "a host of thorny etiquette issues have arisen," writes Dana Hull.

How many charging stations does a company need? One large Silicon Valley employer found that the 16 stations it installed in 2010 has created problems for the 61 employees (of the 1,800 member work force) who drive electric vehicles today. So how many chargers should an accommodating employer provide?

According to the operator of the world's largest network of electric vehicle charging stations, ChargePoint, "they need one charging port for every two of their employees' electric vehicles," writes Hull. But even in Silicon Valley, famous for the perks many companies lavish on their workers, adding charging stations may be difficult "as many companies lease their facilities instead of owning them outright, making them loath to install permanent infrastructure. In addition, the chargers themselves are expensive."

"If you don't maintain a 2-to-1 ratio, you are dead," said ChargePoint CEO Pat Romano. "Having two chargers and 20 electric cars is worse than having no chargers and 20 electric cars. If you are going to do this, you have to be willing to continue to scale it."