Solar has its own vocabulary. Here are the key terms explained in plain English — each one linked to the calculator or guide where it matters most.
A measure of battery capacity: the current a battery can deliver for one hour. Multiply by voltage to get watt-hours of stored energy.
Battery Ah to kWh converter →The maximum current a cable can safely carry before it overheats. Choosing a conductor means keeping the current below its ampacity and within the voltage-drop limit.
Cable size calculator →A group of solar panels wired together. The array's voltage and current depend on how many panels are in series and how many strings are in parallel.
Series & parallel calculator →The compass direction a panel faces. In the northern hemisphere, true south usually captures the most energy over the year.
Panel tilt & angle calculator →A diode built into a panel that lets current flow around a shaded or faulty section, reducing the energy lost when part of a panel is in shade.
Shading loss calculator →The device between the panels and battery that regulates charging and protects the battery. Comes in two types, PWM and MPPT.
MPPT vs PWM charge controllers →The energy lost when a solar array briefly produces more power than the inverter's AC rating can pass, so the inverter caps its output. A little clipping is normal in an oversized array.
DC to AC ratio calculator →The array's DC capacity divided by the inverter's AC rating (also called the inverter loading ratio). Most systems sit around 1.1 to 1.3.
DC to AC ratio calculator →The slow, permanent decline in a panel's output over the years, usually around 0.5% per year, so a panel still makes most of its rated power after 25 years.
Panel degradation calculator →The share of a battery's capacity you can safely use before recharging, roughly 50% for lead-acid and 80 to 90% for lithium. Deeper discharges shorten battery life.
Battery Ah to kWh converter →Reducing a component's rated value to allow for real conditions, most often the drop in panel output as cell temperature rises above 25 degrees C.
Temperature derating calculator →A solar system connected to the utility grid, with no battery, that feeds surplus energy back to the grid and draws from it when the sun is down.
Grid-tied vs off-grid vs hybrid →A system that combines grid connection with a battery, so it can store energy, use the grid as backup, and keep running during outages.
Grid-tied vs off-grid vs hybrid →The current a panel produces at its maximum power point under standard test conditions. Strings in parallel add their Imp values.
Series & parallel calculator →The device that converts the panels' and battery's DC electricity into the AC electricity used by appliances and the grid.
Inverter size calculator →The power of sunlight hitting a surface, measured in watts per square metre. The standard 'full sun' benchmark is 1000 W/m2.
Peak sun hours by location →A panel's short-circuit current, its highest possible current, used for sizing fuses and checking equipment current limits.
Series & parallel calculator →A unit of energy: one kilowatt used for one hour. Your electricity bill, daily use, and battery storage are all measured in kWh.
Battery Ah to kWh converter →A solar array's rated power under standard test conditions, i.e. the sum of the panels' peak wattages. Real output is usually a bit lower.
Solar panel calculator →Maximum Power Point Tracking, a smart charge controller that runs panels at their most productive voltage and converts the surplus into extra current, harvesting 15 to 30% more than PWM.
MPPT vs PWM charge controllers →A billing arrangement where the surplus energy your solar exports to the grid is credited against the energy you later import.
Solar bill savings calculator →A standalone solar system with batteries and no grid connection, which must be sized to cover the load through the night and cloudy days.
Off-grid system wizard →Wiring strings side by side so their currents add up while the voltage stays the same. Used to increase array current.
Series & parallel calculator →The number of hours per day that sunlight would need to shine at full 1000 W/m2 intensity to deliver the day's total energy. Numerically equal to daily kWh/m2.
Peak sun hours by location →The fraction of an array's theoretical output that actually reaches the meter after heat, wiring, dust, and inverter losses, typically 0.75 to 0.85.
Energy production calculator →Pulse-Width Modulation, a simple, cheap charge controller that connects the panel almost directly to the battery, wasting any panel voltage above the battery's level.
MPPT vs PWM charge controllers →Wiring panels end to end so their voltages add up while the current stays the same. Used to reach the inverter's operating voltage.
Series & parallel calculator →The energy an array loses when part of it is shaded. Series-wired panels suffer more because one shaded panel drags down the whole string.
Shading loss calculator →Standard Test Conditions, the lab benchmark panels are rated at: 1000 W/m2 irradiance, 25 degrees C cell temperature, and a set air mass. Real conditions give lower output.
Temperature derating calculator →A set of panels wired in series. The string voltage is the panel voltage times the number of panels, and must fit the inverter's voltage window.
String sizing calculator →How much a panel's voltage or power changes per degree of temperature. Panels lose power as they heat up and gain voltage as they cool.
Temperature derating calculator →The angle a panel is tilted from horizontal. The best fixed tilt is close to your latitude, adjusted for whether you want summer or winter output.
What angle should solar panels be →The voltage a panel produces at its maximum power point. Panels in series add their Vmp to set the string's operating voltage.
Series & parallel calculator →A panel's open-circuit voltage, its highest voltage with no load, which rises in cold weather. A string's cold Voc must stay below the inverter's maximum input voltage.
String sizing calculator →The loss of voltage along a cable due to its resistance. Kept low (usually under 3%) by choosing a thick enough conductor for the current and distance.
Voltage drop calculator →A single panel's rated power under standard test conditions. A 450 Wp panel produces 450 watts at full sun in the lab.
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