Solar & Off-Grid Energy Calculators
From a plain energy audit of the loads through to array size, battery bank, inverter and charge controller — the whole off-grid sizing chain in order.
Energy Load Audit Calculator
Convert appliance watts and daily running hours into a daily energy demand in watt-hours and kilowatt-hours.
E_day = sum(W_i x h_i) Solar Array Sizing Calculator
Number of photovoltaic modules needed for a daily energy demand from peak sun hours and a system derating factor.
P_array = E_day / (PSH x (1 - derate)) ; n = ceil(P_array / P_module) Battery Bank Sizing Calculator
Storage energy and ampere-hours for a daily demand, autonomy period and depth of discharge, with the series and parallel layout.
E_bank = E_day x days / DoD ; Ah = E_bank / V Inverter Sizing Calculator
Continuous and surge inverter rating from the largest load, a load-type surge factor and a design margin.
P_cont = P_load x (1 + margin) ; P_surge = P_load x surge factor Solar Thermal Collector Area Calculator
Size a flat-plate solar thermal collector from a heat balance — once for the daily hot water demand and once for the peak hour — and see which one actually governs.
q_u = eta0*G - U_L*(Tabs - Tf) | A = max(daily energy sizing, peak hour sizing) Charge Controller Sizing Calculator
Charge controller current rating from array watts and battery voltage, with MPPT or PWM correction and 25 % headroom.
I = P_array / V_battery ; I_controller = I x 1.25