Comprehensive Guide to LiFePO4 Battery Voltage and Performance

Posted by

adminw

On August 4, 2024

Comments Off

Lithium Iron Phosphate (LiFePO4) batteries have gained significant traction in various high-performance applications due to their stability, safety, and longevity. This guide provides an in-depth analysis of LiFePO4 battery voltage characteristics, charging and discharging parameters, and compares their performance with other battery technologies.

Table of Contents

Overview of LiFePO4 Battery Voltage

LiFePO4 batteries are known for their stable voltage output and long cycle life. Their voltage characteristics play a crucial role in determining their suitability for different applications, from electric vehicles to renewable energy systems. Understanding these voltage parameters helps users optimize battery performance and lifespan.

What is a LiFePO4 Voltage Chart?

A LiFePO4 voltage chart illustrates the relationship between the state of charge (SoC) and the voltage across various battery capacities. It provides a clear picture of how the voltage changes as the battery discharges, which is essential for effectively managing and utilizing the battery.

Example Voltage Chart for LiFePO4 Cells

SoC (%)	12V Cell Voltage	24V Cell Voltage	36V Cell Voltage	48V Cell Voltage
100	14.6V	29.2V	43.8V	58.4V
90	13.4V	26.4V	39.6V	52.8V
80	13.28V	26.16V	39.48V	52.32V
70	13.2V	26.0V	39.2V	52.0V
60	13.08V	25.76V	38.88V	51.52V
50	13.04V	25.6V	38.4V	51.2V
40	13.0V	25.2V	38.0V	50.4V
30	12.88V	24.96V	37.44V	49.92V
20	12.8V	24.8V	37.2V	49.6V
10	12.0V	24.0V	36.0V	48.0V
0	10.0V	20.0V	30.0V	40.0V

Key Parameters

Nominal Voltage: The average voltage during typical operation. For a 12V LiFePO4 cell, this is 12.8V.
Float Charge Voltage: The voltage required to maintain a fully charged battery without overcharging. For a 12V cell, this is 14.6V.
Discharge Cutoff Voltage: The minimum voltage before the battery should be recharged to prevent damage. For a 12V cell, this is 10V.

3.2V LiFePO4 Battery Charging and Discharging Voltage Chart

LiFePO4 cells typically have a nominal voltage of 3.2V per cell. The following chart provides a detailed breakdown of the charging and discharging voltage for 3.2V cells:

Capacity	Voltage
100%	3.65V
90%	3.50V
80%	3.40V
70%	3.30V
60%	3.20V
50%	3.15V
40%	3.10V
30%	3.05V
20%	3.00V
10%	2.90V
0%	2.50V

12V LiFePO4 Cell Charging and Discharging Voltage Chart

For a 12V LiFePO4 battery, which typically consists of four 3.2V cells connected in series, the voltage characteristics are as follows:

Capacity	Voltage
100%	14.6V
90%	13.4V
80%	13.28V
70%	13.2V
60%	13.08V
50%	13.04V
40%	13.0V
30%	12.88V
20%	12.8V
10%	12.0V
0%	10.0V

24V LiFePO4 Cell Charging and Discharging Voltage Chart

A 24V LiFePO4 battery, typically composed of eight 3.2V cells in series, exhibits the following voltage characteristics:

Capacity	Voltage
100%	29.2V
90%	26.4V
80%	26.16V
70%	26.0V
60%	25.76V
50%	25.6V
40%	25.2V
30%	24.96V
20%	24.8V
10%	24.0V
0%	20.0V

36V LiFePO4 Cell Charging and Discharging Voltage Chart

A 36V LiFePO4 battery, consisting of twelve 3.2V cells in series, has the following voltage profile:

Capacity	Voltage
100%	43.8V
90%	39.6V
80%	39.48V
70%	39.2V
60%	38.88V
50%	38.4V
40%	38.0V
30%	37.44V
20%	37.2V
10%	36.0V
0%	30.0V

48V LiFePO4 Cell Charging and Discharging Voltage Chart

For a 48V LiFePO4 battery, typically comprising fifteen 3.2V cells in series, the voltage characteristics are:

Capacity	Voltage
100%	58.4V
90%	52.8V
80%	52.32V
70%	52.0V
60%	51.52V
50%	51.2V
40%	50.4V
30%	49.92V
20%	49.6V
10%	48.0V
0%	40.0V

Relationship Between State of Charge (SoC) and Voltage

The State of Charge (SoC) of a LiFePO4 battery directly affects its voltage. As the battery discharges, its voltage decreases. This relationship is not linear, which is why battery management systems (BMS) are used to prevent over-discharge and manage charging efficiently.

Voltage vs. State of Charge Table

SOC (%)	Voltage (V)
100	3.65
90	3.50
80	3.40
70	3.30
60	3.20
50	3.15
40	3.10
30	3.05
20	3.00
10	2.90
0	2.50

Charge State Curve

The charge state curve provides insights into how the battery’s voltage changes during charging and discharging. The higher the nominal voltage, the more fully charged the battery is. The curve helps in understanding the battery’s charge and discharge characteristics.