Got a friend with an F150 with the 2kw pro power onboard inverter system trying to charge a Anker 767. It's not working. The ANKER is rated to pull in 1000w AC continuous and it's not getting an overload alert. It's acting like nothing is plugged in at all. The Anker charges from a home outlet no problem. Is this a "floating ground" issue? Or something we're missing?