Solar setup: shade, angle and the controller window

The array is the part of the system that cannot be adjusted once it is fixed down, which is an argument for spending the planning time here.

Survey the shade before choosing the panels

Watch the site across a day, and think about the season. A chimney, an aerial, a roof vent or a neighbouring tree costs more than its shadow suggests, and the cheapest fix is to put the panel somewhere else. A slightly less efficient panel in full sun beats a better one behind an obstruction, permanently.

Decide series or parallel from shade and distance

Series raises the voltage, which suits a long cable run and gives a tracking controller room to work. Parallel keeps the voltage low and confines the damage a shadow does to one panel. On a van roof under trees that argument usually settles itself.

Check the string against the controller window

The controller publishes a minimum voltage below which it will not start, and a maximum it must never see. Open-circuit voltage rises as the cells get colder, so the maximum has to be checked against the coldest clear morning the installation will meet, using the panel maker’s temperature coefficient. This calculation is the one most often skipped and the only one with no warning stage.

Specify the cable and the connectors properly

Cable rated for photovoltaic use — ultraviolet, temperature range, double insulation — sized for the current and the run. Connectors crimped with the matching die and mated with their own kind rather than mixed between brands. Supported so nothing hangs on a connector or chafes on a roof edge.

Mount it the way the hardware says

The panel maker specifies where a frame may be clamped and the mount maker specifies what it holds and in what wind. Both documents exist per product, and between them they cover everything a general page could only guess at.