How do you size a battery bank for solar storage?

Required capacity (kWh) = Daily load (kWh) × Days of autonomy / DoD (depth of discharge). For 10 kWh/day, 2 days autonomy, 80% DoD: 10 × 2 / 0.8 = 25 kWh nameplate capacity.

What is cycle life for lithium vs. lead-acid batteries?

Lithium iron phosphate (LFP): 3,000–6,000+ cycles to 80% capacity. LFP cycle life at 80% DoD: 4,000+ cycles. Lead-acid: 300–500 cycles at 50% DoD. LFP total lifetime kWh throughput ≈5–10× lead-acid.

Battery Storage Sizing Calculator — kWh & Days of Autonomy

Constant	Symbol	Value	Units
Speed of light	c	2.99792458×10⁸	m/s
Planck's constant	h	6.62607015×10⁻³‴	J·s
Boltzmann constant	kʙ	1.380649×10⁻²³	J/K
Avogadro's number	Nₐ	6.02214076×10²³	mol⁻¹
Gravitational constant	G	6.6743×10⁻¹¹	N·m²/kg²
Gas constant	R	8.31446	J/(mol·K)
Elementary charge	e	1.602176634×10⁻¹⁹	C
Electron mass	mₑ	9.1093837015×10⁻³¹	kg
Proton mass	mₚ	1.67262192369×10⁻²⁷	kg
Fine-structure constant	α	7.2973525693×10⁻³	dimensionless

Constant

Symbol

Value

Speed of light

2.99792458×10⁸

Planck's constant

6.62607015×10⁻³‴

Boltzmann constant

kʙ

1.380649×10⁻²³

Avogadro's number

Nₐ

6.02214076×10²³

Gravitational constant

6.6743×10⁻¹¹

Gas constant

8.31446

Elementary charge

1.602176634×10⁻¹⁹

Electron mass

mₑ

9.1093837015×10⁻³¹

Proton mass

mₚ

1.67262192369×10⁻²⁷

Fine-structure constant

7.2973525693×10⁻³

Formula Definitions

The Battery Storage Sizing Calculator — kWh & Days of Autonomy works by applying a well-defined formula to the values you enter. Understanding the formula behind the calculation helps you interpret the result and check that your inputs are correct. Below we break down the key components that drive the Battery Storage Sizing.

The core formula used by this calculator is:

Result = f(physical quantities, constants, conditions)

Each variable in the formula has a specific meaning:

physical quantities — Measured values with units entered into the Battery Storage Sizing.
constants — Physical or chemical constants (e.g. CODATA values, gas constant, Avogadro's number).
conditions — Temperature, pressure, concentration, or environmental state of the system.
Result — Computed physical or chemical quantity with associated units.

Note: Compare results with standard reference values or published experimental data.

How to Use This Calculator

Enter the required values. Enter the required values into the Battery Storage Sizing Calculator — kWh & Days of Autonomy input fields.

Adjust settings. Adjust any settings, select applicable options, or choose units as needed.

Calculate the result. Press Calculate to compute the result using the underlying formula.

Interpret the output. Review and interpret your result using the provided context, reference ranges, or explanatory notes.

Glossary and Definitions

Physical quantity

A measurable property of a physical system, expressed as a numeric value with units.

Constant

A fixed, well-defined value (e.g. a CODATA constant) used across scientific calculations.

Significant figures

The digits in a measurement that carry meaning, reflecting the precision of the instrument.

Reference value

A published standard or experimental value used to validate a calculated result.

Battery storage calculator

A key concept referenced by the Battery Storage Sizing: Size battery storage for solar, off-grid, and backup applications. Calculate required capacity from daily load and days of autonomy.

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A key concept referenced by the Battery Storage Sizing: Size battery storage for solar, off-grid, and backup applications. Calculate required capacity from daily load and days of autonomy.

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A key concept referenced by the Battery Storage Sizing: Size battery storage for solar, off-grid, and backup applications. Calculate required capacity from daily load and days of autonomy.

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A key concept referenced by the Battery Storage Sizing: Size battery storage for solar, off-grid, and backup applications. Calculate required capacity from daily load and days of autonomy.

Battery Storage Sizing Calculator — kWh & Days of Autonomy

Formula Definitions

How to Use This Calculator

Glossary and Definitions

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Frequently Asked Questions