Required Battery Capacity Calculator
Required Battery Capacity Calculator
Work backwards from a backup load and duration to nominal battery capacity.
Working backwards from a load and backup duration gives a nominal storage target rather than just a guessed battery count.
Include the intended energy allowance and inverter idle draw, then choose usable discharge within the manufacturer's limits.
How to use Required Battery Capacity Calculator
- Enter steady AC load, backup duration and energy allowance.
- Enter bank nominal voltage, usable depth of discharge, inverter efficiency and DC idle consumption.
- Select Calculate result. Read the returned values alongside the assumptions below before copying, exporting or acting on the result.
Why choose this tool?
The calculation connects the storage target directly to the hours and load you want to cover.
Before you use the result
Required nominal energy includes the entered allowance and idle draw. Use manufacturer limits to choose usable DoD and discharge capability.
Questions about Required Battery Capacity Calculator
Does capacity alone prove the battery can supply the load?
No. Discharge current, BMS limits and equipment compatibility need a separate check.
What should I check before using Required Battery Capacity Calculator?
Check Steady AC load, Backup duration, Energy allowance and Bank nominal voltage. Use the exact units shown beside the controls and replace any example values with your own inputs.
Related Tools
Explore the other tools in this collection.
Battery Backup Runtime Calculator
Estimate steady AC backup hours from battery energy and an entered load.
Open toolBattery Bank Series and Parallel Calculator
Inspect ideal bank voltage, amp hours and energy from identical battery modules.
Open toolBattery Charging Time Estimator
Estimate ideal bulk equivalent charging time from a state of charge change.
Open toolBattery Energy Unit Converter
Convert between voltage and Ah, Wh, kWh and electricity units.
Open toolBattery Option Comparison Worksheet
Compare entered purchase costs per usable cycle and throughput energy.
Open toolCharge Current and C Rate Calculator
Compare entered charge current with capacity and a manufacturer supplied current limit.
Open toolCold Temperature Voc Calculator
Apply a signed module voltage coefficient to a colder module temperature.
Open toolDC Cable Voltage Drop Calculator
Estimate resistive DC drop in a two conductor circuit from an entered conductor area.
Open toolEssential Backup Load Planner
Choose outage hours for essential appliances and calculate an AC energy budget.
Open toolHome Energy Load Planner
Build an appliance schedule and separate daily energy from connected running power.
Open toolHot Temperature Vmp Calculator
Inspect the operating voltage reduction under an entered hot cell condition.
Open toolInverter Running Load Sizing Worksheet
Compare simultaneous running loads with an entered headroom allowance.
Open toolMonthly Solar Yield Planner
Supply your own monthly sun hours and day counts for a seasonal production worksheet.
Open toolMotor Starting Load Worksheet
Combine one starting appliance with other loads already running.
Open toolMPPT Output Current Worksheet
Estimate battery side controller current from an array power allowance.
Open toolOff Grid Energy and Storage Balance
Estimate array and nominal storage for a daily AC demand and autonomy allowance.
Open toolPV Series and Parallel Array Calculator
Calculate ideal voltage, current and nameplate power for identical modules.
Open toolPV String Limit Checker
Compare a proposed series string against entered cold Voc and hot Vmp limits.
Open toolRoof Panel Footprint Planner
Fit modules into an entered rectangular usable area in two orientations.
Open toolSolar Array Size Calculator
Estimate DC capacity from a daily AC energy target and entered sun hours.
Open toolSolar Generation Estimator
Estimate AC energy after separate DC losses and inverter efficiency.
Open toolSolar Installation Quote Builder
Total a manually priced bill of materials in PKR without fetching market rates.
Open toolSolar Lifetime Cashflow Worksheet
Model annual savings, degradation, maintenance and a one time replacement.
Open toolSolar Loss Chain Calculator
Multiply successive loss factors and see how each stage changes energy.
Open toolSolar Output Degradation Planner
Track an entered first year yield under a constant annual reduction.
Open toolSolar Panel Quantity Calculator
Round a target array up to whole panels and inspect the resulting DC capacity.
Open toolSolar Self Consumption and Export Savings Calculator
Value entered solar use and exports without assuming a current utility tariff.
Open toolSolar Simple Payback Calculator
Compare an entered capital outlay with annual net savings.
Open toolTilted Panel Row Spacing Calculator
Calculate simple geometric shadow clearance for an entered solar elevation angle.
Open toolUsable Battery Energy Calculator
Separate nominal stored energy, usable DC energy and estimated AC output.
Open toolWatts, VA and Power Factor Converter
Convert real and apparent single phase power using the entered power factor.
Open tool