Electrical Engineering

Battery Bank and Inverter Sizing Tool

Quick Answer

Calculates required battery capacity (Ah) and minimum inverter rating (kW) from your daily energy needs, autonomy targets, and system efficiency.

Calculator

Battery Capacity (Ah)
—
Inverter Size (kW)
—

Result Interpretation

Battery Capacity (Ah) tells you the total amp-hour rating needed at your specified voltage. Inverter Size (kW) is the minimum continuous power rating your inverter must support.

Worked Example

Default inputs

Given:

  • energy_consumption_per_day = 2000
  • autonomy_days = 3
  • battery_voltage = 24
  • depth_of_discharge = 0.8
  • peak_load_power = 5000
  • inverter_efficiency = 0.9
  • power_factor = 0.8

Expected Result:

  • out_battery_capacity = 347.222222
  • out_inverter_size = 5.555556

The actual numerical result is computed by the Runtime engine using the persisted tool definition. The values shown here come from verified test cases.

Formula / Method

Battery Capacity (Ah) = (Daily Energy x Autonomy Days) / (DoD x Inverter Efficiency x Battery Voltage) Inverter Size (kW) = Peak Load (W) / (Inverter Efficiency x 1000)

Standard battery sizing formula accounting for usable capacity (DoD) and conversion losses (efficiency). Inverter sized for peak load with efficiency margin

Variables

SymbolLabelRoleDescription
energy_consumption_per_day Daily Energy Consumption INPUT Daily Energy Consumption
autonomy_days Number of Autonomy Days INPUT Number of Autonomy Days
battery_voltage Battery Voltage INPUT Battery Voltage
depth_of_discharge Depth of Discharge (DoD) INPUT Depth of Discharge (DoD)
peak_load_power Peak Load Power INPUT Peak Load Power
inverter_efficiency Inverter Efficiency INPUT Inverter Efficiency
power_factor Power Factor INPUT Power Factor
out_battery_capacity Battery Capacity OUTPUT Battery Capacity
out_inverter_size Inverter Size OUTPUT Inverter Size

Calculation Steps

  1. Enter the daily energy consumption in Wh.
  2. Enter the number of autonomy days in days.
  3. Enter the battery voltage in V.
  4. Enter the depth of discharge (dod) in %.
  5. Enter the peak load power in W.
  6. Enter the inverter efficiency in %.
  7. Enter the power factor.
  8. Step 1: Compute battery capacity.
  9. Step 2: Compute inverter size.
  10. Read the battery capacity (Ah) from the results.
  11. Read the inverter size (kW) from the results.

Engineering Summary

What value does Battery Bank and Inverter Sizing Tool produce for the given inputs? The calculation uses deterministic formula evaluation. This tool is applicable in engineering calculation.

Engineering Applications

Off-Grid Solar Systems

Size battery banks for solar PV installations with specific autonomy requirements.

Backup Power Planning

Determine battery capacity for UPS and emergency backup systems based on daily load profiles.

RV and Marine Power

Calculate battery bank sizing for mobile power systems with limited charging capacity.

Telecom Tower Power

Engineer battery autonomy for remote telecommunications equipment.

Notes / Limitations

  • ASSUMPTIONAll inputs are finite numeric values within the physical range intended by the tool.
  • LIMITATIONResults follow the regenerated deterministic formula exactly; legacy page heuristics (rounding/formatting) are not reproduced.

Frequently Asked Questions

What does Depth of Discharge (DoD) mean?

DoD is the fraction of battery capacity that can be safely used. A DoD of 0.8 means 80% of the rated capacity is usable. Deeper DoD reduces battery lifespan

Why does inverter efficiency matter?

Inverters lose energy as heat during DC-to-AC conversion. Typical efficiency is 85-95%. Lower efficiency means the battery must supply more energy than the load requires

How many autonomy days should I use?

Typical values: 1-2 days for grid-tied backup, 3-5 days for off-grid solar, 5-7 days for critical systems. More days means a larger, more expensive battery bank

What is power factor and why does it matter?

Power factor (0-1) is the ratio of real power to apparent power in AC systems. Resistive loads have PF=1. Motors and electronics may have PF=0.6-0.9. Lower PF requires larger inverter capacity

Technical Details
Assumption
All inputs are finite numeric values within the physical range intended by the tool.
Limitation
Results follow the regenerated deterministic formula exactly; legacy page heuristics (rounding/formatting) are not reproduced.

Browse More Tools

Explore the full index of engineering calculators on this vertical site.