Joel, The "positive ground" refers to the Load connection. I talked to the Renolgy folks and he re-assured me that this was a none-issue.
The controller can disconnect loads in order to maintain a battery, Ods are good, nobody would use that feature in an RV.
On cars, we control loads by turning the power on off. This controller controls loads by switching the ground on/off.
2001 Coachmen Mirada (Ford F53 6.8L V10) - Toad 2001 Civic
It won't do MACH 2, but I can get a sandwich and take a pee.