Panels and generation · Faisalabad, Lahore, Punjab

Huawei SUN2000 shows String Current Backfeed (2012)

Short answer

Alarm 2012 means current is flowing back into one string. Huawei lists the causes as fewer panels in that string than in the strings it is paralleled with, shade on that string, or an abnormal open-circuit voltage. It often follows adding or replacing panels.

What you will see

2012 after panel changes
Lower generation than before

Why it happens

A shorter or shaded string has lower voltage, so the others push current back into it.

Diagram

Mismatched strings push current backwards

Matched

Same panel count and no heavy shade. Current flows forward.

Shorter or shaded string

Lower voltage, so others push current back: 2012.

Huawei SUN2000 inverters; read the alarm ID and cause ID in FusionSolar.

What you can check yourself

Note which input from the cause ID
Check for new shade on that part of the roof

What not to do

Do not rearrange strings yourself

When to call us

Count panels per string
Re-string so parallel strings match

Adding panels later

We redesign strings when Faisalabad and Lahore homes add panels to an existing Huawei system.

Send us

the alarm and roof layout photos