Direct parallel connection of 2 EAST and WEST PV solar strings with (very) different panels and voltages?

[Christophe]

Which amounts to 2 inverters ... So I still don't have an answer to the question!

What are the MC4 parallel connectors for then?

For the strings of the same roof section and without a solar mask?

[Petrus]

The panels are dioded, so normally there is no return of current in the weakest string ... but I still ask myself the question: what happens when a string let's say made for nominal 150V receives 300V at its terminals?

If the diode is made to block the current on 150V max and you apply 300V to it, it will end badly.

[Christophe]

Hence my question !!

How to know simply the blocking capacity of the diode of the panels? I have multimeter with diode function!

[Petrus]

The diode function on multimeters is used to measure forward voltage, not reverse voltage.
To know the reverse voltage, you need the reference of the diode and look for the datasheet.

[izentrop]

Hence my question !!

How to know simply the blocking capacity of the diode of the panels? I have multimeter with diode function!

Must take the reference and consult their datasheet https://www.digikey.fr/fr/products/deta ... BgQAvD_BwE

Otherwise they do not have a reverse voltage of phew, but in the PV we find several in series https://www.researchgate.net/figure/Arr ... _272606392

Otherwise two panels with different output voltages must be connected to separate regulators or inverters

Panels connected in series or parallel should be sorted for the lowest possible mismatch losses.

[phil59]

You put a panel, a micro inverter, connected at worst to a 220V outlet, respecting the phase, it works.

You put 2 panels each with a micro inverter, they will each give the maximum of what they can give.

You put 10 panels on an inverter designed for, in different directions, you will not have the sum of the panels.

Risk of breakdown, yes. But a single inverter for 2 panels, one broken down, no more production ....

I only have 4 panels in production, each with a micro inverter, the maximum that anyone can do.

I recovered 2 inverters, including one to change the relay, but not put into production.

[Christophe]

So the correct answer is that it is not possible directly?

And the same question with 2 strings of identical panels with EAST / WEST orientation?

Morning: 100% EST
Noon: 50/50 (gradually from one to the other ...)
Evening: 100% WEST

The voltage of the panels at 100% would not exceed that of the nominal panels in "standby" mode, so a priori no risk of degradation ... but during the production imbalance what happens?

Would the panels in the sun be clamped by the thong in the shade?

For the moment I see it as 2 batteries in //: it always works better when the right battery is alone ...

[izentrop]

So the correct answer is that it is not possible directly?

And the same question with 2 strings of identical panels with EAST / WEST orientation?

Morning: 100% EST
Noon: 50/50 (gradually from one to the other ...)
Evening: 100% WEST

The voltage of the panels at 100% would not exceed that of the nominal panels in "standby" mode, so a priori no risk of degradation ... but during the production imbalance what happens?

Would the panels in the sun be clamped by the thong in the shade?

For the moment I see it as 2 batteries in //: it always works better when the right battery is alone ...

With a diode in series on each panel, there is only one that produces and not as well as if it were pointed at the sun.
At noon, there is a time when the two panels have the same sunshine, but very weak.
You really have to have the means to waste. For Total, it's a kind of greenwashing

[Christophe]

Your diagram is too small I do not understand ... all the PV panels are already dioded ...

[izentrop]

I enlarged it.
Ia + Ib only works when the voltages at the terminals of the 2 panels are identical, at the zenith. Otherwise only one side will produce.