Q: re Combining Strings and MPPT

[burgerking]

Assume I have several Solar Panels Strings all having almost equal Vopen (difference caused by shade, bird poop, dust ...)
Assume I have multiple Inverters / SCC.

Question:
1. Can I combine several string's Negative into a single wire (PV- Bus) and shared among all Inverters/SCC?
2. Can I combine several string's Positive into a single wire (PV+ Bus) and shared among all Inverters/SCC?
Assume I am using Inverters (Growatt, Deye) with multiple MPPT inputs in a single package:
3. Can I feed each of the MPPT inputs from a shared Positive and Negative PV wire?


I plan to add more panels in the future, and would like to prepare the conduit right now.

 

[TomC4306]

No.
An MPPT SCC is not a passive device. Mean Power Point Tracking means that the charger is changing the output voltage of the solar panels connected to it. If more than one charger were connected to a particular string they would fight one another.

 

[DThames]

MPPT chargers adjust the load in the panels to get the max power from the panels. If you have two MPPTs on one PV source, neither of them can effectively seek the MPPT (Max power point load voltage). The exception (just an example) is you have 2, 50 amp MPPTs (on a 25v battery that would be 1250watts per charger) that will hit 50 amps and will self limit. This is normal, for them to self limit or they would fry themselves. If you connect two such chargers to a PV source that could deliver 5000 watts, then both could charge full capacity when more than 1250x2 watts were available. But when less than 1250x2 watts are available, both would be less effective than when they were working with their own PV source.

You would be better off running several wire runs inside the same conduit and run an extra run, or two runs for future growth.

 

[TomC4306]

Or, use a combiner box at the array location.
Before burying a conduit, you should probably acquire a better understanding of how all this works.
Inverters, scc, electrons...