salience

I would find it incredible if MPP Solar inverters and their clones were NOT compatible with the 2 major brands of solar panels available here in Europe, BENQ and QCELLS. I contacted a retailer of the Inverter WKS II 48V 5kVA - a re-brand or clone of MPP with the same installation instructions, a unit approved here in Europe, and they say the inverter and BENQ are definitely compatible and it is not necessary to ground one or the other pole of the PV array. I am assuming that the answer to all this is contained in the paragraph I posted above about non-isolated inverters: With a non-isolated inverter, the lack of isolation to the grounded ac service conductors requires that the dc PV array be ungrounded for the inverter to work. While this type of system is operating, the dc PV array actually becomes referenced to ground through the ac output conductors. The PV industry often refers to this system configuration as “ungrounded,” but in reality the PV array is only ungrounded when the inverter is not operating. As soon as the inverter begins producing power, the whole system becomes referenced to ground through the ac service conductors." It seems then that the instruction sheet for the BENQ panels assumes that they will be connected to an isolated inverter, and therefore one or the other pole must be grounded. I've not found a contact to write BENQ about this - their instruction manual should be changed to reflect the situation of there being both types of inverter on the market. SO, has anyone here who is using an MPP / Axpert / etc. inverter grounded a power output pole of their PV array?

Seems like some knowledgeable folks here, so here goes...my first question. I am setting up a new grid-assisted system using a MPP SOLAR - AXPERT - SYRIO VM III 5kW Inverter, and the manual states: "WARNING: Because this inverter is non-isolated, only three types of PV modules are acceptable: : single crystalline, poly crystalline with class A rated and CIGS modules. To avoid any malfunction, do not connect any PV modules with possible current leakage to the inverter. For example, grounded PV modules will cause current leakage to the inverter. When using CIGS modules, please be sure NO grounding." However, the manual for my solar panels, BENQ 320W, says: "To achieve optimal system performance, it is recommended to ground the negative (or positive according to model) pole of the solar photovoltaic system array. Failure to correctly ground the system will lower system performance and void the AUO Photovoltaic Module's limited warranty on output." BUT, I found these recommendations in "Bonding and Grounding PV Systems _ IAEI News magazine.htm" "a large percentage of new inverters being installed today have non-isolated ac output circuits. What this means is that the ac output of the inverter does not pass through an isolation transformer the way most grounded dc inverters do. PV systems with grounded dc PV arrays must have an isolation transformer to isolate the grounded dc array from the grounded ac service conductors that it is connected to on the output of the inverter. With a non-isolated inverter, the lack of isolation to the grounded ac service conductors requires that the dc PV array be ungrounded for the inverter to work. While this type of system is operating, the dc PV array actually becomes referenced to ground through the ac output conductors. The PV industry often refers to this system configuration as “ungrounded,” but in reality the PV array is only ungrounded when the inverter is not operating. As soon as the inverter begins producing power, the whole system becomes referenced to ground through the ac service conductors." So, there seems to be some disagreement whether or not to earth the negative or positive of the solar panel array - but I would give precedence to the Inverter Instructions, and NOT ground either side of the solar panel array. Any agreement, or dissenting opinions here? AND, I found this sort of odd statement in the installation manual for QCELLS Q.Peak DUO-G5.X : "Functional Grounding: For installations in tropic regions (between 23.5°N and 23.5°S) with a module of tilt <5°, functional grounding at the negative generator connection on the DC side must be implemented."... WEIRD? Thanks!