JouleCalc — Energy Storage Calculators

Sizing tools for batteries, power stations, and off-grid loads.

Solar & Battery

Solar Battery Bank CalculatorSize an off-grid battery bank from your daily load and days of autonomy — capacity in kWh and Ah, plus a series/parallel layout for the cells you choose.
Solar Panels Needed CalculatorFind how many solar panels cover a target daily energy use, using peak sun hours and a system derate factor.
Inverter Size CalculatorFind what size inverter you need from the appliances you will run — continuous watts, startup surge, and the DC current your battery bank must supply.
DC Wire Size CalculatorPick a copper wire size for a DC run from current, one-way length, and a voltage-drop budget — checked against NEC ampacity, not drop alone.

Power Station Runtime CalculatorEstimate how long a portable power station runs a given load, after inverter and battery-reserve losses.
Appliance Wattage CalculatorAdd up running watts, daily watt-hours, and surge watts for the appliances you plan to power.
Power Station Size CalculatorPick the appliances you need to run and get a recommended power station capacity plus matching models.
Solar Charge Time CalculatorEstimate how long solar panels take to charge a portable power station, in full sun, partly cloudy, or overcast skies.

Home Battery Backup CalculatorEstimate how many hours a home battery will cover a chosen average load during an outage. AC-rated usable energy is used as-is; DC battery energy is reduced by inverter loss.

Appliance Electricity Cost CalculatorEstimate what one appliance costs to run per day, month, and year from its watts, daily hours, and your kWh rate.