The

The short answer is 3 (in other words 12 panels and 3 QS1 microinverters per string).

If you take a look at the

This is where the 80% rule comes in. To be code compliant and avoid overheating, the maximum total AC output needs to be 80% of the max trunk cable current.

This 16A is the code complaint maximum that the trunk cable current can handle safely.

Thus 4 microinverters that would amount to 20A would not fit the 80% rule.

Or another way to put it, for 4 QS1 microinverters, to be code compliant, the maximum AC trunk cable current has to be 24 (which they are not):

**APsystems QS1 microinverter**monitors 4 solar panels, but how many can you put per string? Here’s a short answer and longer explanation.The short answer is 3 (in other words 12 panels and 3 QS1 microinverters per string).

**Here’s the full explanation as to why this is:**

If you take a look at the

**APsystems QS1 Datasheet**you’ll note that each microinverter has a Nominal Output Current of 5A and the Max AC Trunk Cable Current is 20A. 5A x 4 = 20A, so why is the max number of micro inverters per string 3 and not 4?This is where the 80% rule comes in. To be code compliant and avoid overheating, the maximum total AC output needs to be 80% of the max trunk cable current.

20A x 80% = 16A

Thus 4 microinverters that would amount to 20A would not fit the 80% rule.

Or another way to put it, for 4 QS1 microinverters, to be code compliant, the maximum AC trunk cable current has to be 24 (which they are not):

5A x 4 = 20A

20A x 1.2 = 24A

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