Positive or negative controller???

[mudbunny]

It's time to add solar to my van and can't decide which type of controller to get. Right now I am charging my house battery with the alternator by way of a CD solenoid or with shore power and a charger. I have searched sites about this and have gotten different views. Some say you need a negative ground controller while some say to use a positive controller and only use the PV and battery terminals and not the load terminals. As far as negative ground the choices are limited. What are your views on this subject? While I've gotten your attention here's another question.  My van has a fiberglass hitop so the panels won't ground through it, does that mean I'll have to run a ground wire to the chassis?

 

[Optimistic Paranoid]

1:  Never seen a positive ground charge controller.  As far as I know, everybody here is successfully using negative ground controllers on our negative ground vehicles.

2:  The same controllers are also used for wind power systems, and also used to run water pumps on rangeland and such, where there is no battery in the system.  Ignore the "Load" terminals and just stick to the PV and Battery terminals.

3:  99% of solar panels are mounted on residential or commercial buildings.  The National Fire Code REQUIRES all these panels to be grounded to the same ground rod the buildings electrical system is grounded to.  We don't have grounding rods.  On vehicles, you only need to run positive and negative wires to the charge controller, there is no need to ground the panels to the chassis, although it won't hurt anything if you do.

Regards
John

 

[mudbunny]

1:  Never seen a positive ground charge controller.  As far as I know, everybody here is successfully using negative ground controllers on our negative ground vehicles.

2:  The same controllers are also used for wind power systems, and also used to run water pumps on rangeland and such, where there is no battery in the system.  Ignore the "Load" terminals and just stick to the PV and Battery terminals.

3:  99% of solar panels are mounted on residential or commercial buildings.  The National Fire Code REQUIRES all these panels to be grounded to the same ground rod the buildings electrical system is grounded to.  We don't have grounding rods.  On vehicles, you only need to run positive and negative wires to the charge controller, there is no need to ground the panels to the chassis, although it won't hurt anything if you do.

Regards
John

Thanks John but on ebay, Amazon, and solar websites, the majority of  the controllers are positive. Renogy sells both types but recommend negative ground models for rv use. I've read about doing it either way but just don't want the magic smoke.

 

[GotSmart]

Thanks John but on ebay, Amazon, and solar websites, the majority of  the controllers are positive. Renogy sells both types but recommend negative ground models for rv use. I've read about doing it either way but just don't want the magic smoke.

Negative ground.  It makes everything simple.  2 wires, no problems.  Just make sure you have a good ground.

 

[ccbreder]

If your vehicle is negative ground, go with that. If you can only get a positive ground controller, be very careful to have it isolated from the vehicle except at the battery connections.