Lekker SunSolar design guides
Practical notes for solar installers and designers, from string voltages on a cold morning to explaining payback to a client. Each one ends with how to check it in the Lekker Sun designer.
How to check string voltage for cold weather
Solar panel voltage rises as it gets colder. How to work out the coldest-morning open-circuit voltage of a string, the MPPT window and the current limits, with a worked example.
About 7 minutes to readHow partial shading affects solar panels
Why a small shadow can cost a large share of a solar panel's output, what bypass diodes do, and how panel orientation, half-cut cells and optimisers change the result.
About 6 minutes to readHow to account for trees in a solar shading study
Trees are the hardest objects to model in a solar shading study. How tall they will grow, how much light the crown lets through, and how long winter shadows get.
About 6 minutes to readChoosing solar panel orientation and tilt
Which way solar panels should face, how steep they should be, when east and west roofs make sense, and how far apart to space rows on a flat roof.
About 7 minutes to readHow to size a home battery from the load profile
A practical way to size a home solar battery: start from the evening and night load, allow for depth of discharge and efficiency, and check the inverter's charge and discharge limits.
About 7 minutes to readUsing smart-meter data to build a load profile
How to turn a smart-meter export into a load profile for solar and battery design: intervals, kW versus kWh, missing data, time zones and existing solar.
About 6 minutes to readSolar payback, NPV and IRR explained
How to explain a solar system's return to a client: simple payback, payback with tariff increases, net present value and internal rate of return, with a worked example.
About 7 minutes to readDC/AC ratio and inverter clipping
Why solar arrays are often larger than their inverter, how much energy clipping really costs, and the inverter limits to check before oversizing.
About 6 minutes to read