All calculators
Each tool is generated from a JSON definition and the same calculator engine. Clusters group related math for internal linking and search.
Battery storage
Cluster pagebattery storage
Amp-Hours (Ah) to Watt-Hours (Wh) Converter
Convert battery amp-hours to watt-hours for 12V, 24V and 48V systems. Wh = Ah × V.
battery storage
Battery Bank Sizer for RV/Van
Size a 12V, 24V or 48V house battery bank from daily watt-hours, days of autonomy and LiFePO4 or lead-acid depth of discharge.
battery storage
Battery C-Rating & Max Discharge Calculator
Convert a battery C-rate into maximum continuous amps and watts, and see how hard a given load is on the pack.
battery storage
Battery Charging Time Calculator
Estimate how long a 12V, 24V or 48V battery takes to recharge from a shore charger or alternator, including 90–95% charging efficiency.
battery storage
Battery Runtime Calculator
Estimate how many hours a 12V, 24V or 48V battery will last under a given load. Accounts for LiFePO4 and lead-acid depth of discharge (DoD).
battery storage
Lead-Acid to LiFePO4 Upgrade Calculator
See how many amp-hours of LiFePO4 replace a lead-acid or AGM bank of the same usable energy, plus the weight you save.
battery storage
Trolling Motor Battery Calculator
Estimate trolling-motor amp draw from thrust and voltage, then see runtime from a 12V, 24V or 36V battery bank.
Solar panels
Cluster pagesolar panels
Off-Grid Cabin Daily Solar Need
Add up fridge, lights, laptop, water pump and other cabin loads to get a daily watt-hour budget for solar sizing.
solar panels
Series vs Parallel Solar Calculator
Add Voc in series and Isc in parallel to check string voltage, array current and nameplate watts against your MPPT limits.
solar panels
Solar Array Sizer
Estimate how many solar panels you need from daily watt-hours, panel watts and peak sun hours, including a realistic derate.
solar panels
Solar Panel Temperature Loss Calculator
Estimate how many watts a solar panel loses when cell temperature rises above 25°C using the Pmax temperature coefficient.
solar panels
Solar Roof Space & Weight Calculator
Estimate square meters of roof and kilograms of dead load for a given number of solar panels.
solar panels
Solar Tilt Angle & Azimuth Estimator
Estimate annual, summer and winter solar panel tilt from latitude, plus true-south or true-north azimuth.
Inverters and charge controllers
Cluster pageinverters
Generator Sizing for Battery Charging
Size a backup generator for a battery charger from DC charge current, battery voltage and charger efficiency.
inverters
Inverter Idle Draw Battery Drain
See how many watt-hours and amp-hours a switched-on inverter wastes overnight with no load.
inverters
Inverter Sizing Calculator
Size a pure sine inverter from continuous watts, motor surge and inverter efficiency with 25% headroom.
inverters
MPPT Charge Controller Sizer
Size an MPPT charge controller from array watts and battery voltage, with 20% current headroom and Voc margin.
inverters
PWM vs MPPT Efficiency & Yield Comparison
Compare daily watt-hours from a PWM charge controller versus MPPT when panel Vmp is above battery voltage.
Wiring and electrical safety
Cluster pagewiring
DC Inline Fuse & Circuit Breaker Sizer
Size a DC fuse or breaker at 125% of continuous current, then check it against copper cable ampacity.
wiring
DC Voltage Drop Calculator
Calculate copper DC voltage drop in volts and percent for a chosen AWG, current and one-way cable length.
wiring
12V/24V/48V DC Wire Gauge (AWG) Calculator
Pick a copper AWG size for 12V, 24V or 48V DC runs from current, one-way length and a 3% voltage-drop budget.
wiring
Grounding Rod & Wire Sizer
Estimate copper GEC size for a ground rod or other electrode and EGC size from the DC overcurrent device.
wiring
Solar Combiner Box Fuse Sizer
Size PV string and combiner fuses at 1.56 × Isc and see when three or more parallel strings need fusing.
Appliance-specific
Cluster pageappliances
CPAP Machine Battery Run Time
Estimate watt-hours and battery amp-hours for a CPAP night, including humidifier draw and inverter losses.
appliances
Electric Bike / Onewheel Solar Charging Sizer
Estimate AC watt-hours and solar array watts to recharge an e-bike or Onewheel pack from peak sun hours.
appliances
12V Compressor Fridge vs Residential 110V Fridge
Compare daily watt-hours of a 12V compressor fridge against a household fridge running through an inverter.
appliances
Pellet Stove / Heater Battery Backup Sizer
Size a battery backup for a pellet stove from circulating-fan watts plus igniter surge energy.
appliances
RV Air Conditioner Solar Sizer
Estimate daily watt-hours, battery amp-hours and solar array watts to run a rooftop RV air conditioner off-grid.
appliances
Starlink Off-Grid Power Consumption Calculator
Estimate daily watt-hours and amp-hours for Starlink Mini, Standard and Performance dishes, including snow melt.
appliances
Off-Grid Well Pump Solar Sizer
Size solar, battery and inverter surge for a well pump from running watts, LRA surge factor and daily pump hours.