I went serial for 3 reasons:
1. Less expensive wiring and connections.
2. Less wiring loss for a given wire size.
3. Better shaded power output due to bypass diodes.
My 3 series panels have 61' (including pigtails) of 10ga wire resulting in a voltage drop of 0.55%.
My 3 panels with 7 of the 9 bypass diodes conducting (ie shade on 7 panel sections) produce 20V and hence the CC will charge. I've posted graphs showing the charging variations in leafy shade from 20V to 90V. The changes occur at 20V, 30V, etc up to 90V. There is no question from posted information and my checking that serial with bypass diodes has better shade power.
The differences aren't gigantic however. As the saying goes just add another panel which is especially true at today,s lower prices.
