Complete Guide to LiFePO4 Voltage Chart

You must have heard of LiFePO4 batteries. They are akin to the reigning power in the world of batteries, owing to their safety, longevity, and electrifying performance. Yet, even these strong powerhouses require a little something to understand them. That is the LiFePO4 voltage chart.

The LiFePO4 voltage chart provides us with a complete guideline about the battery’s inner workings. It teaches us about the battery’s optimal usage, maximum lifespan, and how it can have a harmonious partnership with other energy backup systems.  

LiFePO4 Batteries

Before proceeding to understand the LiFePO4 voltage chart, let us first have an understanding of the LiFePO4 batteries. After all, the LiFePO4 voltage chart is akin to the secret language of LiFePO4 batteries. How can we understand this secret language without first comprehending its main context? 

LiFePO4 batteries - short for the term Lithium Iron Phosphate batteries - have revolutionized the world of energy storage. They are a form of lithium-ion batteries, especially acclaimed for their safety, longevity, and performance. 

Unlike other lithium-ion batteries that use heavy metals like cobalt and nickel, LiFePO4 batteries do not use them. This makes LiFePO4 batteries more environmentally friendly than their peers. Their structure is also more stable, thereby significantly reducing fire hazards. 

Another lovely feature of LiFePO4 batteries is their long life span. Their life cycle exceeds 3,500 cycles at 80% depth of discharge, thereby handling thousands of charge and discharge cycles before reaching their degradation phase. 

There are also other superior qualities of LiFePO4 batteries that you will love. For one, its charging speed is much faster than its lithium-ion counterparts. It continues to maintain a consistent voltage throughout its performance, and it has a much greater storage capacity than its peers.

How awesome their features are! Aren’t you now tempted to obtain these batteries for your power backup devices? However, before you go to buy them, be sure to understand the LiFePO4 voltage chart.

Basics of Battery Voltages 

There are several basic battery voltage terms that we must first understand before proceeding to learn about the LiFePO4 voltage chart. 

Nominal Voltage

The nominal voltage refers to the optimum voltage at which the battery works best. It is an ideal point, though the real voltage is mostly never set at this nominal voltage. 

What it does is serve as a set standard, allowing you to monitor the charging and discharging of your battery. It is around 3.25V for LiFePO4 batteries. 

Fully Charged Voltage 

A fully charged voltage pertains to the maximum voltage of a battery when it is charging. This is the highest recommended voltage that a battery should reach. It is 3.65V for LiFePO4 batteries.

Going any higher than this leads to potential safety hazards; thus, you should make sure to understand what the fully charged voltage of your battery is and never exceed it. 

Storage Voltage

As its name suggests, the storage voltage is the optimum and ideal voltage at which a battery should be stored when not in use for longer durations. 

Since the storage voltage is imperative in maintaining battery health and minimizing capacity loss, you should know this figure on the voltage chart for your battery. 

Discharge Voltage 

The discharge voltage refers to the voltage value below which a battery must never be discharged. It is done so for its safety; you will only be harming your battery if you do so. It is 2.5V for LiFePO4 batteries. 

Since it is the minimum safe operating limit, knowing this value will ensure that you never unintentionally end up harming your battery. 

Deep Discharge

Contrary to the discharge voltage, the deep discharge is the point where the battery voltage falls far below the recommended discharge voltage. This deep discharge inadvertently reduces the battery’s lifespan and capacity.

Therefore, you must also know about this figure for your battery to ensure that no such harm is done.

Understanding the LiFePO4 Voltage Chart

Wondering why there was a need to first understand the battery voltage terms before moving on to the LiFePO4 voltage chart. Well, you will know the answer in a while. 

The LiFePO4 battery voltage chart shows the state of charge in 1 cell at different voltages, like 12V, 24V, and 48V. Below is the table that shows the SOC (state of change) of a single cell. It allows you to estimate the remaining energy in the battery based on its current voltage. 

Chart Layout

Reading the LiFePO4 voltage chart requires you to understand what each of its X-axis, Y-axis, and curve/line represents. 

X-Axis OR Capacity/Time Axis

The horizontal axis is termed the X-axis. On the LiFePO4 voltage chart, the X-axis represents the percentage of discharge or time. 

Y-Axis OR Voltage Axis

The vertical axis is known as the Y-axis. On the LiFePO4 voltage chart, the Y-axis represents the voltage levels in increments. 

Curve/Line

Lastly, there is the curve or line on the LiFePO4 voltage chart. This curve or line represents the fluctuating charge or discharge of the battery.

The above 12 LiFePO4 shows how voltage drops with regard to battery capacity. Moreover, for a 24 LiFePO4 Battery system, you can either purchase one 24V LiFePO4 battery or two 12V batteries and connect them in series. Typically, a 48V LiFePO4 battery is used for larger systems. 

Below is the chart for a 48 LiFePO4 Voltage Chart:

Interpreting the Chart

Having understood the layout of the LiFePO4 voltage chart, let’s proceed to learn how to interpret the said chart.  

Charging Phase

The rising curve is the LiFePO4 battery’s charging phase. When the LiFePO4 battery is in its charging phase, the voltage rises. 

The LifePO4 voltage chart shows this exact phase by the rising of the curve towards a higher voltage.

Discharging Phase

Besides an ascending curve, you will also observe a descending curve in the LiFePO4 voltage chart. It represents the discharging phase of the LiFePO4 battery. It is so because while discharging, the LiFePO4 battery’s voltage drops. 

Battery and Voltage Relationship Table

Stable Voltage Range

You will also see a flat portion of the curve in the LiFePO4 voltage chart, displaying a relatively stable voltage. Thus, this section represents the voltage where the LiFePO4 battery is in its storing voltage phase. 

Critical Zones

There are two critical zones on the LiFePO4 voltage chart you need to keep an eye on. These are the fully charged phase and the deep discharge phase. 

Exceeding the normal readings for the LiFePO4 battery’s charge and discharge voltage and entering these critical zones significantly reduces the LiFePO4 battery’s lifespan and capacity. 

Charging Parameter Table

LiFePO4 Float, Bulk, and Equalize Voltage

There are three common types of voltages - namely, bulk, float and equalize, though lithium supports only bulk voltage. Nevertheless, let us look at each one of them.

Bulk voltage: Bulk voltage pertains to the level of voltage required to charge the battery quickly when it is almost empty. For a 12V LiFePO4 battery, the bulk voltage is around 14.6V.

Float voltage: A lower voltage figure than bulk voltage, it keeps the battery fully charged without overcharging it. For a 12V LiFePO4 battery, the float voltage is around 13.5V.

Equalize voltage: Equalise voltage is essentially a maintenance routine done periodically to maintain the battery’s capacity and performance. It ensures that all parts of the battery are working properly. For a 12V LiFePO4 battery, the equalized voltage is around 14.6V - the same as the bulk voltage. 

Battery Discharge Graph

The graphs below show the relationship between the discharge rate and the battery capacity use. The battery discharge curve offers insights into the efficiency, performance, and operational lifespan of Lithium-ion batteries, when under different loads. 

Benefits of Understanding the LiFePO4 Voltage Chart

After having understood how the LiFePO4 voltage chart works and what it represents, you will be awed by how many benefits you reap in terms of understanding your LiFePO4 battery. 

Optimize Battery Usage

When you have understood the LiFePO4 voltage chart of your LiFePO4 battery, you can now easily determine the charging and discharging voltages of your LiFePO4 battery. 

In doing so, you can now effectively realize how to maximize your LiFePO4 battery’s lifespan and capacity and make sure not to exceed its optimum charge and discharge voltage.

Monitoring Battery Health

When you are constantly checking your LiFePO4 battery’s voltage against the LiFePO4 voltage chart, you can effortlessly detect if your LiFePO4 battery is displaying unsafe voltage levels. 

In this process, you can take immediate action to safeguard your LiFePO4 battery so that no harm comes to it.

Estimating Run Time 

After you have successfully understood the voltage-to-capacity relationship, it will be easy for you to realize how much load your battery can handle and how long it can run under said load conditions.

It will help you choose which devices to attach to your battery and which to not do so.

Practical Applications of LiFePO4 Batteries

You will be using the LiFePO4 voltage chart wherever there are LiFePO4 batteries involved, whatever power backup system they are in. One particular setting where you will definitely find LiFePO4 batteries is the various BLUETTI solar power backup systems. 

If you have BLUETTI products, you will surely love to learn about the LiFePO4 voltage chart that will aid you in understanding your LiFePO4 batteries. 

Let’s look at some BLUETTI products with LiFePO4 batteries.

1. BLUETTI AC200MAX Expandable Power Station

The BLUETTI AC200MAX Expandable Power Station is a remarkable product that can be used as both a home power backup system and as your backup power in outdoor activities.

Key Features:

Power Inverter: Featuring a 2,200W AC Pure Sine Wave Inverter, this system will give you continuous power of up to 2,200W.

Surge Capacity: This system is even capable of handing a surge power of up to 4,800W. This makes it especially useful for running devices that require a higher starting power.

Battery: Boasting a LiFePO4 battery, offering over 3,500 life cycles until it degrades to 80% of its capacity, you are guaranteed maximum durability. 

Expandability: Its power storage capacity is enhanced even further with its expandability up to 6,144Wh with two B230 batteries and 8,192Wh with two B300 batteries.

2. BLUETTI AC300 + B300 Home Battery Backup

The BLUETTI AC300 + B300 Home Battery Backup is another system ideal for large-scale home backup, off-grid living, or extensive power requirements. 

Key Features:

Power Inverter: It promises you a high-quality power output with its 3,000W AC Pure Sine Wave Inverter.  

Battery Capacity: It has a capacity of 3,072Wh, which is expandable with up to 12,288Wh with four B300 batteries. Cool, isn’t it?

Battery: The LiFePO4 battery, which offers more than 3,500 life cycles until the capacity reduces to 80%, is yet another notable feature.

240V Split Phase Bonding: You can even power heavy-duty appliances with this system because its configuration allows for the creation of a 240V connection.

Find out how to choose the best whole house solar power generator for home. 

Final Words 

Now, after having read through this whole article, you must have an understanding of how to read and understand the LiFePO4 voltage chart. You now also know how useful LiFePO4 batteries are in your power backup systems.

Therefore, you should always opt for the LiFePO4 batteries whenever purchasing any type of power backup system. When selecting such a system, BLUETTI’s products are simply the best choice.