positive ground controllers????

[karl]

So I bought one of those $149. -100 w renogy panels with a 30a controller kits.... to my surprise, on the controller is a label stating that "These are Positive Ground Controllers. .......if the vehicle has negative ground on the chassis, loads connected to the controller must not have an electrical connection to the vehicle body".
So, do I now have to have a disconnect(solenoid?) for the negative on my house battery?
Or, a different controller?
Why would it be designed with + ground?

 

[karl]

Thanks, I'll call the tech.
Probably should have mentioned that I am charging the house batt off the alt too.