lifepo4 batteryge lithium iron phosphate LiFePO4 battery?

When switching from a lead-acid battery to a lithium iron phosphate battery. Properly charge lithium battery is critical and directly impacts the performance and life of the battery. Here we’d like to introduce the points that we need to pay attention to, here is the main points.

Charging lithium iron phosphate LiFePO4 battery

Charge condition

Just like your cell phone, you can charge your lithium iron phosphate batteries whenever you want. If you let them drain completely, you won’t be able to use them until they get some charge. Unlike lead-acid batteries, lithium iron phosphate batteries do not get damaged if they are left in a partial state of charge, so you don’t have to stress about getting them charged immediately after use. They also don’t have a memory effect, so you don’t have to drain them completely before charging.

ELB LiFePO4 batteries can safely charge at temperatures between -4°F – 131°F (0°C – 55°C) – however, we recommend charging in temperatures above 32°F (0°C). If you do charge below freezing temperatures, you must make sure the charge current is 5-10% of the capacity of the battery.

Voltage requirement

ELB Lithium Iron Phosphate (LiFePO4) 12V batteries should be charged at 14.4 Volts (V). For batteries wired in series multiply 14.4V by the number of batteries. For example, a 24V battery bank requires a charger voltage of 28.8V , 36V requires 43.2V, etc.

ELB Lithium Battery Voltage | Recommended Charging Voltage | Recommended Charging Speed (C)

12 Volts | 14.4 Volts | <0.3C (3 hours or more)

24 Volts | 28.8 Volts | <0.3C (3 hours or more)

36 Volts | 43.2 Volts | <0.3C (3 hours or more)

48 Volts | 57.6 Volts | <0.3C (3 hours or more)

60 Volts | 72.0 Volts | <0.3C (3 hours or more)

72 Volts | 86.4 Volts | <0.3C (3 hours or more)

What is the battery voltage when my battery is full or depleted?

Batteries measure around 14.4V when they are fully charged and quickly drop to about 13.4V when the charger is removed.

They provide consistent power between 13.4 to about 12.8V and quickly deplete to 9.7V at the end of the discharge. ELB Lithium Iron Phosphate batteries have a flat voltage curve. This means that the voltage will be fairly steady throughout use, and only drop below a useful voltage when the battery is nearly empty.

Lead acid batteries have a steep voltage drop and it is common that a lead acid battery’s voltage is no longer useable when the battery still have 60% of capacity left.

This flat voltage curve is why ELB Lithium batteries have twice the usable power even though the battery has the same amount of energy inside the battery.

A 100Ah ELB Lithium battery will last twice as long as a 100Ah AGM or lead acid battery even though the name plate or energy rating is the same. Please note: Seeing a low voltage of <1V is evidence that the B.M.S. is triggered.

Which kind of lithium charger can I use for LiFePO4 batteries?

Most LiFePO4 chargers have an output of 14.6V – 14.8V which will charge ELB Lithium batteries, and any LiFePO4 fully.

No special brand requirement, other programmable chargers can also be used if needed and should be set to output 14.4V and disconnected after charging.

VRLA chargers and other lithium-ion batteries’ chargers do not output the correct voltage for charging the battery fully.

Can I charge my LiFePO4 lithium battery with lead acid charger?

Charging type

Other sellers out there claiming you can use your existing lead acid charger. The reality is that there are only a very limited few that will accurately and safely charge a Lithium Iron Phosphate battery correctly and to full states of charge, whilst doing so efficiently especially when using solar when you want to get the maximum output from it to your batteries.

Lithium batteries require a Constant current/Constant voltage (CC/CV) charge type with simple Bulk, Absorption, Float stages.

Why the answer is “No”?

Many lead acid chargers have desulphation and equalisation stages built in, which will pulse high voltages of 15.3-15.8V into the battery. This is really important to correctly charge and to maintain lead acid batteries, to avoid stratification of the electrolyte and ensure proper voltage equalisation of the cells, but are definitely not suitable for LiFePO4 batteries. It can heavily reduce the life of the cells due to regular over voltage charging or cause irreversible damage to the battery.

Or lead acid chargers have equalization as an automatic stage that cannot be turned off.

When these stages kick in, they will cause pretty much every good quality LiFePO4 battery on the market with an internal BMS to go into high voltage disconnect protection mode at around 15.0V – the battery goes open circuit and the charger and all loads disconnect before starting all over again once it resets (if it auto resets – not all BMS will do this automatically). For those that don’t, the battery is open circuit and turned off till you realised and take action to reset it. For those that do, you then get an on/off/on/off scenario for many hours leading to poor charge performance and sometimes never getting out of those stages for many hours.

In conclusion

No matter what they say in their marketing (which is really all it is – a made up marketing spiel) about their supposedly magic batteries that you can use any charger on, it is just totally wrong and demonstrates a total lack of understanding of LiFePO4 chemistry, the narrow voltage range that it operates in and the effects of using a multi-stage Lead acid charger to charge LiFePO4 cells.

There is a lot more to it than just outline above, but it does get into a very technical discussion which is outline below if you want more info.

Firstly it’s important to understand the voltage range that each battery type operates in. A lead acid battery typically will be fully charged at 12.6-12.8V. But LiFePO4 battery will be 13.3-13.4V. A lead acid battery. LiFePO4 batteries operate in a very narrow voltage range with only 0.5V from full all the way down to 20% state of charge. Even at 25% state of charge it will still be at approx 12.8V whereas a lead acid battery at 25% state of charge is around 11.7V with a range of over 1.1V.

How long does it take to charge lithium batteries?

One of our most frequently asked questions is “how long does it take to charge lithium batteries?”

Our experts note charging time depends on the specific charger in your system. Lithium-ion batteries have low internal resistance, so they will take all the current delivered from the current charge cycle. For example, if you have a 50-amp charger and a single 100-amp hour battery, divide the 100 amps by 50 amps to come up with a 2-hour charging time.

Another example is if you had five 100Ah (amp-hour) batteries for a total of 500Ah and a 100-amp charger. It would take about 5 hours of charging from empty to 100 percent while factoring in enough time to balance the charging cycle.

We don’t recommend you exceed this charge rate as it can lead to a shortened battery cycle life. In an emergency, the battery can be charged at a quicker rate if needed. But we don’t recommend you make a habit of emergency charging your battery.

How do I store my LiFePO4 lithium battery better?

We recommend to store LiFePO4 batteries at about 50% state of charge (SOC).

If we store the long periods of time, cycle the batteries at least every 6 months. Do not store batteries without (Fully discharged). They do not require a trickle charger.

Recommended storage temperature: -5 to +35°C (23 to 95 °F)

Storage up to 1 month: -20 to +60°C (4 to 140 °F)

If storage up to 3 months: -10 to +35°C (14 to 95 °F)

Extended storage time: +15 to +35°C (59 to 95 °F)

It is highly recommended to store lithium batteries indoors during the offseason.

Are LiFePO4 lithium battery safe?

Yes, LiFePO4 is a safe chemistry and the most stable lithium-type battery on the market.

ELB lithium is UL 1642 certified, which means they have been tested for short-circuit, abnormal charging, crush, impact, shock, vibration, heating, temperature cycling and pressure, .

All ELB LiFePO4 batteries come with an internal Battery Management System. The BMS protects against

Under-Voltage – during discharge

Over-Voltage – during charge or regen conditions

Over-Current – during discharge

Low-Temperature – during charge and discharge

High-temperature – during charge and discharge

Short-Circuit Protection – protects battery cells from damage

Single Cell Equalization and balancing

Want to produce customized lithium battery according to special requirement, welcome to consult ELB team to get more details.

4 Best Ways To Charge a LiFePO4 Battery

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4 Best Ways To Charge a LiFePO4 Battery

Solar Batteries

4 Best Ways To Charge a LiFePO4 Battery

Ana Lejtman

9335 Views

If you’re looking to prolong your battery life while still maintaining its performance, then knowing the best ways to charge a LiFePO4 battery will really come in handy.

There are several lithium battery chemistries currently on the market, but the LiFePO4 is undoubtedly the best one to date, particularly for applications that require a large battery bank.

Due to its extremely stable chemistry, LiFePO4 (Lithium Iron Phosphate) batteries provide a much safer option than other lithium technologies, which can lead to a fire if mishandled.

The LiFePO4 batteries are also much more resistant and can withstand electrical and thermal abusive conditions. This means they can stand the test of time, performing a large number of cycles without compromising their performance.

Despite being more expensive than its lithium or lead-acid counterparts, LiFePO4 batteries are an excellent long-term investment if — and that’s a critical condition — they are properly maintained.

This article will provide the 4 best ways to charge a LiFePO4 battery. This will assist those of you who’re aiming to get the most out of your battery system and make it a worthwhile investment.

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Do LiFePO4 Batteries Need A Special Charger?

This is a very common question that comes up when one considers switching to Lithium Iron Phosphate batteries.

The short answer is no — a special charger is not exactly a requirement. What is required, though, is that the charger supplies the battery with the appropriate charging specifications.

But what does that mean? What are the charging specifications of a LiFePO4 battery?

To answer these questions, let’s first revisit a few relevant concepts:

Charging

Charging a battery simply means applying an external voltage to force the flow of electrons (current) from the cathode to the anode. While discharging, the electrons flow in the opposite direction.

Voltage

Voltage is a force that makes electric charges move. In other words, voltage is the pressure in which the current moves through an electrical system.

Batteries are an assembly of several cells. The number of cells in a battery will determine its nominal voltage.

Lithium Iron Phosphate cells have a nominal voltage of 3.2V, so placing four cells in series provides a nominal voltage of 12.8V. Lead-acid batteries cells have a 2V output, so six cells in series result in a 12V nominal voltage.

This nominal voltage compatibility makes the LiFePO4 a viable alternative to lead-acid batteries.

For the current to flow to the battery – and effectively charge it – the external voltage applied should be slightly higher than the open-circuit battery voltage.

But if the applied voltage is too high or too low, the battery won’t charge because the BMS protection will kick in. Or, in a worst-case scenario, the battery will die.

So, to properly charge a LiFePO4 battery, make sure to respect the voltage specifications provided by the battery manufacturer.

Below is a table showing the usually recommended charging parameters of a LiFePO4 battery:

System VoltageCharging Parameters12V14V – 14.6V24V28V – 28.6V36V42V – 42.8V48V56V – 57.8V

This table shows that you can charge your 12V LiFePO4 battery with any type of charging equipment, as long as the charging voltage is within the 14V to 14.6V range.

But of course, just because you can, doesn’t mean you should. So here we present the 4 best ways to charge your LiFePO4.

4 Best Ways To Charge A LiFePO4 Battery

1. Using A Smart Charger

Ok, we know this might sound obvious, but it’s simply the truth — we couldn’t just skip this one.

One of the best ways to charge a battery is using a charger that matches the battery’s chemistry since each one has its particularities.

An example of a smart charger from Victron Energy, with built-in Bluetooth so you can remotely check the status of the battery.

A smart charger can be adjusted according to the LiFePO4 battery charging profile. This maximizes the battery’s performance and lifespan by using an optimized charging technology.

LiFePO4 Battery Charging Profile:

Graph showing a typical charging profile of a 12V LiFePO4 battery.
Source: solacity.com

Having looked at the graph, you’ll see that there are two stages:

Stage 1, “bulk” — The battery is provided with a constant charging current, while the voltage gradually increases. This stage usually takes 1 to 2 hours.

Stage 2, “absorption” — When the charging voltage reaches a little over 14V, the state of charge of the LiFePO4 battery is at around 90%. At this point, to reach full charge, the charging voltage becomes constant, while the charging current decreases to around 5% to 10% of the battery’s Ah rating.

Unlike Lead-acid technologies, it’s not necessary to float charge LiFePO4 batteries. In fact, they can last longer if not constantly kept at 100%.

In addition, LiFePO4 batteries don’t need equalization, nor do they require temperature compensation (required when charging a lead-acid battery). So a proper LiFePO4 charger should not perform these features.

To summarize, you can program a smart charger to provide the LiFePO4 with its specific charging conditions. This way, you can’t go wrong.

2. Using A Lead-Acid Battery Charger

So you’re considering switching your lead-acid deep cycle batteries to brand new LiFePO4 batteries (smart move) and you’re wondering if you’ll need a new charger?

The good news — not necessarily! Most lead-acid battery chargers will do the job just fine.

As long as the charging settings are within the acceptable parameters for LiFePO4 batteries, it’s possible to charge these batteries with lead-acid battery chargers.

Because lead-acid batteries (AGM and Gel) and LiFePO4 have similar nominal voltages, AGM and Gel charging algorithms typically meet the LiFePO4 charging voltage requirements.

An important difference between these batteries is that, unlike the lead-acid batteries, LiFePO4 batteries don’t rapidly lose charge when disconnected. This means that float charging is not necessary.

So when using a lead-acid battery charger to charge a LiFePO4 battery, the float charge option should be switched off. If that’s not possible, the float stage voltage should be set low enough so it can never be reached. Setting the floating voltage under 13.6V is good enough.

In addition, LiFePO4 batteries don’t need equalization or temperature compensation. So disabling these features is also necessary.

If these required adjustments cannot be made to the lead-acid battery charger, then buying an appropriate LiFePO4 battery charger (or a smart charger) is highly recommended.

3. Using Solar Panels

Using a solar energy system to charge LiFePO4 batteries is not only possible but highly encouraged.

That’s because the energy being stored is not just being taken from another energy source (like shore power), it’s actually being generated by solar panels.

A simple solar panel system scheme.
Source: literoflightusa.org

Whether in a home, a boat, or an RV, a solar energy system looks pretty much the same (as shown in the scheme above):

1. Solar panels: convert energy from the sunlight into electrical energy.

2. Charge controller: regulates the power output of the solar panels according to the battery’s charging requirements, avoiding battery overcharge.

3. Battery: stores the energy provided by the solar panels as chemical energy.

4. Inverter: converts direct current (produced by solar panels) into alternating current (which the appliances can actually use).

Once again, correctly sizing the components is key to maintaining the system running appropriately.

So using a charge controller that can efficiently charge the LiFePO4 battery – respecting its charging requirements – is crucial to ensure that the battery functions well and for a long time.

4. Using An Alternator (And A DC-DC Charger)

And last but not least, another great way to charge a LiFePO4 battery is using an alternator. This is a great solution for RVs and boats that have a battery storage setup.

What Is An Alternator?

An alternator is simply a generator that converts mechanical energy into electrical energy. It generates alternating current (hence the name), which the rectifier attached to the alternator then converts into direct current.

This device is an essential part of every combustion engine vehicle’s electrical system. It charges the starter battery, used to start the vehicle’s engine.

With a few adjustments, you can use this electrical system to charge your battery bank (in this case, LiFePO4 batteries) while driving your vehicle.

A system scheme in which an alternator is used to charge a battery bank.
Source: custommarineproducts.com

The above image shows a DC/DC charger as a necessary part of the system.

Because LiFePO4 batteries have a low internal resistance when not fully charged, they can draw any amount of current from the alternator, which can overheat the alternator and damage the battery.

A DC/DC charger acts by limiting the current drawn from the alternator, avoiding the overheating issue. It also regulates the output voltage to the required charging voltage of the LiFePO4 battery, protecting it from overcharging.

Here’s a video made by Victron Energy showing what happens to an alternator if not protected from overheating:

What Happens Inside A LiFePO4 Battery When It Is Charged?

Before we can successfully answer this question, here are a few important things to know:

Lithium Iron Phosphate cells are made of four main components:

Cathode: LiFePO4

Anode: Graphite (which stores lithium by intercalation)

Electrolyte: Lithium Salts in organic solvent

Separator: Polyethylene microporous membrane

Below is an illustration that helps to understand the charging process:

A simple scheme of the charging process in LiFePO4 cells.
Source: “Adaptive state of charge estimation for battery packs” – Saeed Sepasi

So when a LiFePO4 is charged, the application of external power forces the electrons to flow to the negative electrode. This result is the flow of lithium ions from the cathode to the anode.

When discharging, the opposite happens. Lithium ions move from the anode to the cathode, while electrons flow to the positive electrode, through the load.

Once fully charged, the lithium ions in the battery are located mostly in the graphite, so there aren’t many electrons left to move from the cathode to the anode.

At this point, the application of external power should stop. Battery Management Systems detect when the battery is fully charged and cease the charging process, avoiding overcharging.

What Is The Safest Way To Charge A LiFePO4 Battery?

Unlike other lithium battery chemistries, the LiFePO4 is very safe due to its superior thermal and chemical stability.

That’s because LiFePO4 is naturally a stable compound. The P – O bond (in the PO43- species) is quite strong, so when the battery is abused (overcharged or short-circuited), the oxygen atoms aren’t released so easily.

As a result, lithium iron phosphate cells are much harder to ignite. This is an important feature that makes them far superior to other Lithium battery chemistries.

Even though LiFePO4 batteries are a relatively safe technology, it’s extremely important to respect the charging parameters discussed in this article in order to avoid safety risks.

The safest way to charge these batteries would be respecting the exact specifications of the battery, in terms of voltage, optimal charging temperature, use of appropriate wires, etc, whether you use a LiFePO4 charger, a solar system, or any other way.

Tip: Always check your battery’s manual to see what the manufacturer recommends in terms of charging.

Final Thoughts

LiFePO4 batteries offer a great battery storage solution and can be used for various applications. Their thermal and chemical stability makes them very safe when compared to other battery chemistries, but this comes at a very high price – literally.

What makes this investment worthwhile is the promise of a very long battery life, with little maintenance and high performance. Manufacturers claim these batteries can perform thousands of cycles and last from 8 to 10 years if the recommended charging instructions are meticulously followed.

So now that you know the best ways to charge LiFePO4 batteries, which method will you use to charge yours?

Charging LiFePO4 Batteries

Every day we get questions about charging LiFePO4 batteries and lithium battery chargers. We’ve reviewed products that work well with our Battle Born LiFePO4 batteries. To begin the series we will discuss the basics of charging batteries, and the products will be covered in other segments.

Charging a LiFePO4 Battery

Charging a LiFePO4 battery basically means applying an external voltage to drive current from the anode to the cathode of the battery. The lithium battery charger acts as a pump, pumping current upstream, opposite the normal direction of current flow when the battery discharges.

When the charger’s applied voltage is higher than the open-circuit battery voltage, then the charging current flows. During this process, the battery’s open-circuit voltage increases, approaching the applied voltage of the charger.

Bulk Vs. Float Charge

The lithium battery charger can behave in several different ways during the charging process. First, the charger can steadily increase its voltage in order to keep the current flow constant. This is the first stage of the charging process – typically called the “bulk” charging stage. During this stage, the charger adjusts its applied voltage to deliver the maximum current to the battery.

For example, a 10 amp charger will deliver its maximum of 10 amps during this bulk charging stage, and the applied voltage will increase up to a maximum voltage, or “bulk voltage.”

Once the bulk voltage is reached, the charger enters a second stage, called the “absorption” charging stage. During absorption, the charger applies a constant voltage, called the “absorption voltage.” As the battery’s open-circuit voltage approaches the absorption voltage, the current flow steadily decreases down to zero.

At this point, the battery is fully charged. However, a lead-acid battery will rapidly lose charge when the charger is disconnected. So, instead of turning off, the battery charger enters a third stage called the “float” stage, in which the charger drops to a lower voltage and holds at that voltage. The point of this stage is to keep the battery topped off, and account for the fact that lead-acid batteries tend to drain, even when there is no load connected.

The Charging Algorithm

These stages combined sequentially form what is commonly called the “charging algorithm.” A battery charger may generally be classified by a charging current (i.e. the max charging current) and a target battery voltage (12 V, 24 V, 36 V, 48 V, etc.). But battery chargers may also include multiple charging algorithms (typically classified as “AGM,” “SLA,” “Gel,” “Wet,” etc.). A closer look reveals that each algorithm has its own unique parameters, including:

• Bulk voltage
• Absorption voltage
• Absorption time
• Float Voltage

There is a wide variation among values for charging algorithms for lead-acid batteries. The bulk and absorption voltages typically vary between 14.0 and 14.8 V, and the float can vary between 13.2 and 13.8 V.

The 12V Battle Born Batteries sit comfortably right in the middle of these ranges. We recommend a bulk and absorption voltage of 14.4 V. A float is unnecessary, since li-ion batteries do not leak charge, but a floating voltage under 13.6 V is fine.

Here are a few FAQ videos that talk about charging LiFePO4 batteries.

In this blog series, we will post the results of our tests for a variety of LiFePO4 chargers – including converters, inverter chargers, and solar charge controllers. In each case, we will report on the uniqueness of the charging algorithms for each brand, explore the efficacy of using the factory default settings for charging Battle Born Batteries, and determine what can be done to achieve the optimal settings.

If you have any questions or concerns about charging LiFePO4 batteries, please contact us at any time at (855) 292-2831 or email us at [email protected].

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Want To Learn More About Electrical Systems and Lithium Batteries?

We know that building or upgrading an electrical system can be overwhelming, so we’re here to help. Our Reno, Nevada-based sales and customer service team is standing by at (855) 292-2831 to take your questions!

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