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.
Panel & Array Design
Estimate panel output, count panels, optimize tilt angle and size PV strings.
- Solar Panel Output CalculatorCalculate solar panel kWh output per day, month and year. Free solar panel calculator kWh and wattage estimator with daily and annual production based on peak sun hours.
- 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.
- 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 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.
- 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.
Battery & Storage
Battery runtime, bank sizing, charge time and complete off-grid system design.
- 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.
- 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.
- 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.
Economics & System Design
Load audits, inverter sizing, DC losses, array oversizing and payback economics.
- Energy Consumption CalculatorAudit daily energy use by appliance group: watts × hours for lighting, refrigeration, electronics and more — with battery and solar array translation.
- Inverter Sizing CalculatorSize an inverter from continuous load, surge requirement and power factor. Pure sine guidance and idle-draw warnings included.
- DC/AC Ratio CalculatorCalculate the DC/AC ratio of a PV system and estimate annual clipping loss from peak-hour production. Inverter oversizing guidance included.
- PV DC Cable Loss CalculatorCalculate DC voltage drop and power loss in PV string cabling from string voltage, current, run length and cable size — with the 2% design target.
- Solar Savings CalculatorCalculate solar system savings and payback from production, electricity rates, self-consumption and installed cost. 25-year outlook included.
Design guide
How these calculations fit together in real projects — the order to run them in, and the decisions each one answers.