How Solar Sizing Works In GridGap
The Solar tab answers a practical question. How much array do you need if the system has to cover daytime use and, where applicable, help refill the battery too.
What the Solar tab is doing
This is not just a panel counter. The result is trying to turn daily energy demand into an array that still makes sense once sun hours, installation losses, and cloud assumptions are taken into account.
That is why the tab mixes energy values with panel counts and layout hints. One part shows how much solar work needs doing. The other part shows what that answer looks like as a set of panels.
Input reminder cards
The first set of cards reminds you which solar assumptions shaped the result: Panel Size, Panel Voc, Panel Vmp, Effective sun hours, Installation efficiency, and Cloud factor.
If the final panel count feels wrong, start here. A large solar result is often driven by one of these assumptions rather than the panel maths itself.
Energy requirement build-up
The middle section shows how the requirement is built. Day load Wh and Solar energy for day loads cover the daytime part of the job.
If the scenario expects solar to help put energy back into the battery, you will also see Battery recharge Wh and Solar energy for battery recharge. That split matters because it shows whether the array is being driven by live daytime use, battery recovery, or a mix of both.
Total solar energy required pulls those pieces together. Then Required solar W turns the daily burden into a practical array target.
When the panel count jumps more than expected, this is usually the section that explains it.
Panel count and string guidance
Raw minimum panel count is the energy-based minimum before practical cleanup. Installed panel count is the final whole-panel count the app suggests after turning the energy answer into something that can be built more cleanly.
The next cards show how that count is being arranged: Panels per string, String count, Estimated string Vmp, Estimated string Voc, and PV voltage limit. They help keep the result grounded, but they do not turn GridGap into a final PV design tool.
Day-only panel count and Battery-recharge panel count help when you want to know what is really driving the array. One shows the daytime share. The other shows the recovery share.
Actual installed solar then shows the final installed wattage implied by the chosen panel size and installed panel count.
Cloud sensitivity and surplus
Solar surplus / shortfall is a planning view of how the final installed solar compares with the modelled requirement. It is useful, but it is not a promise of what every real day will look like.
The Cloud sensitivity panel counts section shows how different cloud assumptions can change the panel count. If those numbers swing a lot, the result is sensitive to site conditions and weather assumptions.
The Indicative string guidance notes are also worth reading. They usually explain why the installed panel count does not exactly match the raw minimum.