Calculators

The arithmetic that decides an off-grid system. Each one shows its method and says what it does not account for, because for this subject a number without its assumptions is not much use.

• Wire Gauge and Voltage Drop

  Sizes a conductor for both ampacity and voltage drop, and tells you which one decided the answer.

• Appliance Power Budget

  Turns a list of appliances into daily watt-hours and the inverter size they need, with duty cycle handled properly.

• Battery Bank Runtime

  How long a bank runs a load, accounting for depth of discharge, inverter losses, and the Peukert derate on lead-acid.

• System Sizing

  Daily energy use into array wattage, battery bank capacity, and charge controller current.

• Outage Runtime

  How long a portable power station will run a fridge, or anything else, during an outage.

• Solar Well Pump Sizing

  Total dynamic head and daily energy for a water pump, sized on the depth to standing water rather than the depth of the well.