Panel groups & orientations
Last updated · how we source this
Most roofs aren’t one flat surface — they’re several faces pointing different directions, at different pitches, with different shade. How you group panels across those faces is the first real design decision, and getting it wrong quietly throws away energy. This module is about laying out orientations the right way.
Tilt and azimuth, defined
- Tilt (pitch) — how steeply the panels are angled from flat (0° = flat, 90° = vertical). Fixed rooftop systems usually sit near the roof’s slope.
- Azimuth — the compass direction the panels face. In Texas (northern hemisphere), south is the production sweet spot; east/west splits trade a little total output for a better match to morning/evening use; north-facing is weakest.
An orientation is simply a group of panels that share the same tilt and azimuth — i.e. panels on the same roof face.
Why you group by roof face
Here’s the key idea: panels wired in series into a string all run at the same current, and that current is set by the weakest panel in the chain. Put a strong south-facing panel and a weak north-facing panel on the same string and the south panel is dragged down to the north panel’s level. So you keep each roof face on its own group — and ideally its own MPPT (Module 5) — so each produces its best independently.
Shading hurts more than you’d think
Because of that same “weakest link” effect, even partial shade — a vent pipe, a chimney, a tree branch at 4 p.m. — can cut a whole string disproportionately, not just the shaded panel. Panels have bypass diodes that limit the damage, and grouping shaded areas separately (or using microinverters/optimizers) helps. The simulator estimates this from your roof’s shade and reports it as a near-shading loss.
Sizing the groups to the roof
Each face also has a usable area — after setbacks and obstructions — which caps how many panels fit there. Part of design is balancing “put the most panels on the best (south) face” against “use the east/west faces to add capacity and spread production across the day.”
Try it in the editor
In the system editor, create a separate orientation for each roof face. The tilt and azimuth are detected from your roof automatically — check them, and adjust if a face is wrong. Then add the panels that physically fit each face. You’re building the groups now; Modules 4–5 wire them into strings and onto MPPT inputs.
Recap
- Group panels by roof face (shared tilt + azimuth) — never mix orientations on one string.
- South is best in Texas; east/west shifts output toward morning/evening; north is weakest.
- Partial shade penalizes the whole string, so isolate shaded areas.
- Respect each face’s usable area.
With your groups defined, Module 4 sizes the strings — how many panels in series keep each group inside the inverter’s voltage window, hot day and cold morning alike. (Coming soon.) Until then, try a layout in the simulator.
This course teaches you to design and model a system. Physical wiring, MPPT/battery connection, and grid interconnection are licensed-electrician work under the NEC — design here, build with a pro.