Solar Power

Parallel versus Serial connection of Solar Panels

Depending on how much shading you expect and what controller type you use can the Serial connection provide extra power with an MPPT controller. But serial connection can also be very bad when shading occur.
This is tested with 2 x Hightec 200 Watt Solar Panels, 75 Feet of 10 Gauge Solar Wire, MorningStar TS-MPPT-60 solar controller.
Serial full sun 265 Watt
Parallel full sun 250 Watt (6% loss)
Serial half shaded 130 Watt (50% loss)
Parallel half shaded (200 Watt (25% loss)
The parallel connection is losing power based on the total current. In overcast conditions is the Parallel production very similar to Serial when the current is lower.