What Size LiFePO4 Battery Do I Need? – A B2B Sizing Guide

Introduction

One of the most common questions B2B buyers ask is: “What size LiFePO4 battery do I need for my project?”

The answer depends on three factors: your power requirements, your application, and your budget. Choosing the right size is critical—too small and your system won’t perform; too large and you’re wasting money.

This guide will walk you through a simple 3-step process to calculate the right battery size for your application.

For a complete overview of LiFePO4 battery sourcing across all applications, see our B2B Sourcing Guide.

Step 1: Calculate Your Daily Energy Consumption

Start by listing everything you need to power and how long you need it to run.

Quick Formula

Battery Capacity (Ah) = (Daily Energy Consumption (Wh) × Days of Autonomy) ÷ (Battery Voltage × Depth of Discharge)

Example Calculation

Scenario: You need 3,050Wh of daily energy with 2 days of autonomy, using a 12V LiFePO4 battery at 80% depth of discharge.

Battery Capacity (Ah) = (3,050Wh × 2) ÷ (12V × 0.8)
= 6,100 ÷ 9.6
= 635Ah

Result: You would need approximately 635Ah of battery capacity at 12V.

Step 2: Choose Your System Voltage

The voltage you choose affects system efficiency and scalability:

For more detailed guidance on voltage selection, see our guide.

Step 3: Apply the 80% Rule

LiFePO4 batteries should not be fully discharged regularly. For maximum cycle life, use 80% depth of discharge (DoD) as your planning target.

B2B Buying Tip: Always plan for 20% extra capacity to account for aging and peak loads. A 100Ah battery bank should be sized to 120Ah for a 100Ah usable load.

Common Application Sizing Guidelines

For RVs and Campervans

For Solar Storage Systems

For Golf Carts and Commercial Fleets

Need a custom recommendation? Enerbe offers custom configurations for fleet, solar, and industrial applications. Contact our team for a tailored sizing guide.

Sizing Checklist for B2B Buyers

• List all loads and calculate daily consumption (Wh)□

• Determine desired days of autonomy□

• Choose system voltage (12V, 24V, or 48V)□

• Apply 80% depth of discharge for planning□

• Add 20% extra capacity for aging and peaks

• Match inverter and charge controller compatibility

Frequently Asked Questions

Q1: How many Ah do I need for a 1000W load?

For a 1000W load running 8 hours at 12V: 1000W × 8h ÷ 12V = 667Ah per day. With 80% DoD, you would need approximately 834Ah of total battery capacity.

Q2: What size battery for a 5kW solar system?

A 5kW solar system typically generates 20kWh per day. At 48V, with 80% DoD: 20,000Wh ÷ 48V ÷ 0.8 = 520Ah. Recommended: 48V 300-400Ah.

Q3: Can I connect multiple batteries to increase capacity?

Yes. You can connect batteries in parallel to increase total capacity. For example, two 100Ah batteries in parallel = 200Ah total capacity. Always use identical batteries and ensure proper BMS settings.

Q4: What happens if I undersize my battery?

Undersized batteries will be deeply discharged frequently, significantly reducing cycle life. You may also experience system shutdowns during peak demand.

Q5: What happens if I oversize my battery?

Oversized batteries cost more upfront but provide longer runtime and extended cycle life due to shallower daily discharges. This can be a cost-effective long-term investment for critical applications.

Summary

Sizing a LiFePO4 battery correctly comes down to three steps:

1. Calculate your daily energy consumption

2. Choose your system voltage

3. Apply the 80% depth of discharge rule

A properly sized battery saves money, extends lifespan, and ensures reliable operation. If you’re unsure, start with your daily energy needs and add 20-30% buffer.

Enerbe provides LiFePO4 batteries in 12V, 24V, and 48V configurations from 50Ah to 300Ah. For custom sizing, wholesale pricing, or a personalized recommendation, contact our team.

All technical information in this guide is provided for informational purposes. Battery sizing requirements may vary by application.

---

Get In Touch

Ready to source LiFePO4 batteries for your project? Contact Enerbe today:

📄 Request a Technical Datasheet – Contact Us  
📞 Speak with Our Engineering Team – Get In Touch  
🔗 Browse Our Custom Battery Solutions – View Products

---

**Dongguan A&S Power Technology Co., Limited.**  
Building 1, No. 2, Keji 9th Road, Songshan Lake, Dongguan, Guangdong, China  
📞 +86 137 1383 1631 | ✉ info@aspowerbattery.com

Stay Charged. Stay Connected：