Lithium Battery Bank Calculator

Battery Bank Capacity Formula:

\[ \text{Battery Capacity (Ah)} = \frac{\text{Daily Energy Consumption (Wh)} \times \text{Days of Autonomy}}{\text{Battery Voltage (V)} \times \text{Depth of Discharge} \times \text{Efficiency}} \]

Daily Energy Consumption:

Days of Autonomy:

days

Battery Voltage:

Depth of Discharge:

decimal (0-1)

System Efficiency:

decimal (0-1)

Required Battery Bank Capacity:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Battery Bank Capacity?

The battery bank capacity calculation determines how much energy storage (in amp-hours) you need to meet your power requirements for a specified number of days without recharging, while accounting for system efficiency and battery discharge limits.

2. How Does the Calculator Work?

The calculator uses the following equation:

\[ \text{Battery Capacity (Ah)} = \frac{\text{Daily Energy Consumption (Wh)} \times \text{Days of Autonomy}}{\text{Battery Voltage (V)} \times \text{Depth of Discharge} \times \text{Efficiency}} \]

Where:

Daily Energy Consumption — Your total daily power needs in watt-hours
Days of Autonomy — How many days you need the system to run without charging
Battery Voltage — System voltage (typically 12V, 24V, or 48V)
Depth of Discharge — How much of the battery capacity you can use (0-1)
Efficiency — System losses from wiring, inverter, etc. (0-1)

Explanation: The equation converts your energy needs into battery capacity while accounting for real-world system losses and battery protection.

3. Importance of Proper Sizing

Details: Correct battery sizing ensures your system meets your power needs while maximizing battery life. Undersizing leads to power shortages, while oversizing increases costs unnecessarily.

4. Using the Calculator

Tips: For lithium batteries, typical Depth of Discharge is 0.8-0.9. System efficiency is typically 0.85-0.95 for well-designed systems. Always round up your final Ah calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why use Depth of Discharge in the calculation?
A: It accounts for the fact that you shouldn't fully discharge batteries to maximize their lifespan. For lithium, 80-90% DoD is typical.

Q2: What's a typical system efficiency value?
A: For DC systems, 0.95 is common. For AC systems with inverter, 0.85-0.9 is typical.

Q3: How do I determine my daily energy consumption?
A: Sum the watt-hours of all devices you'll power, multiplied by hours used per day. Many appliances list their consumption.

Q4: What voltage should I use?
A: Match your system voltage (12V, 24V, or 48V). Higher voltages are more efficient for larger systems.

Q5: Should I add a safety margin?
A: Yes, it's recommended to add 10-20% to the calculated capacity to account for aging and unexpected loads.