PV upgrade decision

MrWizard wrote:

Sunpower used to require their panels be positive grounded. If I'm reading the spec. sheet right this one does not require that. However, I'd verify for sure because it would probably be really hard to have a positive ground solar system in a negative ground RV.

there are quite a few controllers that are 'common positive' and 'control the negative' side of charge circuit

i don't remember seeing anything about 'grounding' the positive of the panels

common and ground are NOT always the same thing, in electrical circuits
grounding in a vehicle is the chassis, which by USA standards is negative
grounding in buildings is earth ground for AC power

Common in DC circuits is the common power or common return, the part NOT controlled
in a vehicle this is the Negative aka chassis

IF Sun recommends Grounding the positive of the panels
this would be in a commercial install and would be an earth bond for the positive side of the panels before connecting to a grid tie inverter,
this is lighting protection
the earth is Positive with respect to the Clouds

and has nothing to do with the actual electrical operation of the panel OR with mounting it on an RV

I'm well aware of the difference between common and ground. Older Sun Power panels did indeed require the positive wire to be grounded. This worked fine with grid tie inverters that used an isolating transformer. It would NOT work if you were trying to charge a battery that had it's negative connected to ground like in an RV.
As I mentioned however, it appears that with these new Sun Power panels they have dropped the positive ground requirement, thankfully. But, I would verify with Sun Power before purchasing.