Suggestion/request: Solar PV strings in parallel, blocking diodes or not.

[SpeedyDave]

Dave,
Would it be possible to do a EEVblog video on the how and why of paralleling solar PV "strings" that would have different orientations (i.e. one string east and 1 west) connected to the same MPPT input on the inverter.

Some info states that the strings must be "exactly the same number and spec" panels, or on a roof angle less than 15 gerees, or exactly east and west etc etc.

I do not believe it!

Given that the inverters MPPT basically is a variable voltage sink, where it clamps its input voltage (the PV output voltage) and then just lets the amps flow, and given that the PV panels/strings have a relatively high impedance, i reckon that two strings of different open circuit voltages on different orientations can easily be paralleled into on MPPT if each string is fed via  suitable blocking diodes, as each string voltage will rise to the point of forward conduction of its blocking diode. Yea, the current flow will be different between each string, but I believe that each string would contribute to the total power in the same way that paralleled caps of different sizes do.

I would REALLY like your highly qualified technical opinion on this ! ( this could also be highly relevant to solar pv design / install people, as it would allow for more diverse installations )

Cheers
Speedy