SolarEdge SE K-AU I Series Quick Installation Manual page 6

Step 1
Check string polarity and measure each string's voltage to verify 1±0.1V per optimizer
Example: 8 optimizers = ~8V
To minimize electromagnetic interference (EMI), make sure to minimize
the distance between the positive and negative DC cables
1 2 3 4 5
8V
MAN-01-00695-1.1 5 5