4 tools
Solar calculators
A useful solar design keeps energy, weather and equipment limits separate. These tools turn daily loads into storage and array requirements, estimate charging from a local solar resource, and check both sides of an MPPT controller.
Solar energy and storage
Size the array and battery bank from daily energy, design-season sunlight and the autonomy you need.
Solar Panel Size Calculator
Turn a daily energy target and local peak-sun resource into array watts, then round up to whole panels without hiding system losses.
Solar Battery Bank Calculator
Calculate the nominal kWh and amp-hours needed to carry your loads through the chosen number of low-solar days, with every derating visible.
Solar charging
Estimate battery charging from available solar energy and choose a controller without overlooking its voltage limit.
Solar Battery Charging Time Calculator
Estimate how many design-solar days an array needs to move a battery from its starting SOC to the target, with array and charging losses shown separately.
Solar Charge Controller Size Calculator
A controller must pass two different limits: battery-side charging current and the PV array's highest possible open-circuit voltage. This tool checks both.
Methodology
How these tools are built
Every calculator here shows the formula it uses, the assumptions behind it and the limits of the model. Where a figure is a typical published value rather than a specification, it says so and lets you change it.