Solar, Energy & Batteries Calculators

Design tools for off-grid and backup solar systems. Sizing includes realistic derating factors (inverter efficiency, depth of discharge, temperature) and every assumption is stated on the page.

• Solar Panel Output CalculatorCalculate solar panel energy output per day, month and year from wattage and local peak sun hours, with a documented derate factor for real-world losses.
• Battery Runtime CalculatorCalculate how long a battery will run a given load, including depth of discharge and inverter efficiency. Shows usable energy and daily consumption.
• Off-Grid System CalculatorSize a complete off-grid system: battery bank Ah, panel array Wp and inverter rating from your daily energy use, autonomy days and sun hours.
• Charge Controller CalculatorSize MPPT or PWM solar charge controllers correctly: MPPT by array watts and system voltage with margin, PWM by array short-circuit current.
• Solar String Size CalculatorSize PV strings correctly: cold-temperature Voc vs inverter max input, Vmp vs MPPT window, array Isc and power. Prevents the most common design failure.
• Battery Bank Size CalculatorCalculate battery bank Ah and kWh from daily energy use, system voltage, depth of discharge and autonomy days. Series/parallel layout guidance.
• Battery Charge Time CalculatorCalculate battery charging time from capacity, charger current and charge window, with C-rate check and chemistry-specific taper notes.
• Solar Savings CalculatorCalculate solar system savings and payback from production, electricity rates, self-consumption and installed cost. 25-year outlook included.
• Solar Panel Tilt CalculatorFind the optimal solar panel tilt for your latitude: annual optimum, winter and summer settings, with azimuth guidance for each hemisphere.
• Solar Panel Count CalculatorCalculate how many solar panels you need for a target daily or monthly energy target, with roof-space estimate and array size.