What is the Difference Between a BMS and a Balancer?

When utilizing lithium batteries in any application, the terms 'Battery Management System' (BMS) and 'balancer' often surface. Though they are both critical for battery health and efficiency, they fulfill different roles within the battery's ecosystem. Understanding these differences is essential for anyone engaged in the DIY off-grid energy space.

The Role of a Battery Management System (BMS)

A BMS is an electronic system incorporated within lithium battery packs. It's responsible for protecting lithium cells against a multitude of risks that can reduce the battery's lifespan or lead to unsafe conditions. These risks include overcharging, deep discharging, operating under high or low temperatures, and handling excessive current. If any of these parameters are exceeded, the BMS intervenes by disconnecting the flow of current to or from the battery bank, effectively mitigating potential damage.

The Function of a Balancer

On the other hand, a balancer is designed to ensure uniformity among the cells in a battery pack. Over time, individual cells within a lithium battery can develop variations in charge levels, which can affect performance and longevity. A balancer corrects these imbalances by evening out the state of charge across all cells.

Types of Balancers: Passive vs. Active

Balancers are categorized into passive and active systems:

• Passive Balancers: These systems level the charge by dissipating the excess energy from more charged cells as heat. This process is simpler and less costly but is not energy-efficient since the excess charge is not reused but lost.

• Active Balancers: In contrast, active balancers redistribute energy from cells with a higher charge to those with a lower charge. This method not only maintains balance but also conserves energy within the battery system, enhancing overall efficiency.

Both a BMS and a balancer are integral to the health and functionality of lithium battery packs. A BMS protects against unsafe operating conditions, while a balancer ensures all cells work cohesively, maintaining balance and extending the battery's service life. For individuals invested in creating sustainable energy solutions, comprehending the distinct functions of these systems is invaluable.

For a deeper exploration into the specific types of balancers and their benefits, visit our detailed articles: What is a Passive Balancer? and What is an Active Balancer Module?.

What is the Lifespan of a LiFePO4 Battery?

Understanding the Longevity of LiFePO4 Batteries

Table of Contents

1. Introduction to LiFePO4 Batteries
2. Lifespan: How Long Can You Expect a LiFePO4 Battery to Last?
3. Key Variables Impacting the Durability of LiFePO4 Batteries
4. Best Practices for Extending Your LiFePO4 Battery Life
5. Frequently Asked Questions

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LiFePO4 batteries have gained a reputation for their impressive cycle life and reliability. When it comes to choosing a resilient battery, LiFePO4 frequently stands out for its extended lifespan, lighter mass, and superior safety attributes.

So, what is the actual lifespan of a LiFePO4 battery? And how do you make it last as long as possible? In this guide, we will break down these questions and more.

Introduction to LiFePO4 Batteries

LiFePO4 stands for Lithium Iron Phosphate, a type of lithium-ion battery that has become increasingly popular for uses beyond just golf carts and marine applications. Its application has expanded to consumer electronics, with some gadgets containing as many as 16 LiFePO4 cells.

Lifespan: How Long Can You Expect a LiFePO4 Battery to Last?

A well-maintained LiFePO4 battery can have a lifespan ranging from 5 to 10 years. The longevity of these batteries is closely tied to how well they are looked after.

Number of Charge Cycles for LiFePO4 Batteries

LiFePO4 batteries are known for their robust 3,000 to 5,000 charge cycles, considering an 80% depth of charge. This significantly outperforms traditional lead-acid batteries, which usually last for about 650 charge cycles.

Key Variables Impacting the Durability of LiFePO4 Batteries

Various factors can either extend or reduce the lifespan of your LiFePO4 battery, such as how you store it, maintain it, and the frequency with which you charge it.

Here are some effective tips to ensure you get the most out of your battery:

• Avoid Overcharging: Overcharging can generate excessive heat and risk a fire. LiFePO4 batteries should only be charged up to 3.5v per cell to maintain a safe temperature.

• Proper Storage: To maximize battery life, LiFePO4 batteries should be stored in a cool environment, ideally between -20°C and 25°C.

• Avoid Over Discharging: The recommended depth of discharge (DoD) for LiFePO4 batteries is 70%. Over discharging can cause irreparable damage to the cells.

Best Practices for Extending Your LiFePO4 Battery Life

1. Use Compatible Chargers: Ensure you are using the charger designed for your specific battery type.

2. Minimize High-Power Applications: Certain apps and functions can quickly drain your battery. Reducing their use can extend battery life.

3. Regular Terminal Check: Periodically examine the terminal bolts for any sign of loosening or oxidation and clean them as needed.

Frequently Asked Questions

In summary, while LiFePO4 batteries may have a higher upfront cost, their extended lifespan and superior performance attributes make them a worthwhile investment. If you are diligent about its storage and charging conditions, a LiFePO4 battery can offer reliable, long-term service, outperforming traditional lead-acid batteries in most aspects.

Remember, the key to longevity is proper maintenance and understanding of how to best care for your LiFePO4 battery.

What is the Best LiFePO4 Battery Cell for DIY Battery Packs? [2023 Edition]

Choosing the perfect LiFePO4 battery cell for your DIY battery pack can be challenging, especially with the multitude of options available. In this comprehensive guide, we break down top LiFePO4 battery cell manufacturers, compare the best models, and help you decide which LiFePO4 battery cell will suit your DIY project best.

Table of Contents

1. Introduction to LiFePO4 Batteries
2. Top LiFePO4 Battery Cell Manufacturers
3. Comparative Analysis of Popular Brands
4. Best Choice for DIY Battery Packs
5. Most Cost-Effective Options
6. Final Thoughts

Introduction to LiFePO4 Batteries

LiFePO4 (Lithium Iron Phosphate) batteries offer superior safety features, long lifespans, and are eco-friendly. They are an ideal choice for DIY battery packs for various applications, including solar energy systems, backup power solutions, and electric vehicles.

Top LiFePO4 Battery Cell Manufacturers

CATL

• Key Models: 280Ah, 302Ah
• Applications: Electric vehicles, Energy Storage

EVE

• Key Models: 230Ah, 280Ah, 304Ah
• Applications: Commercial vehicles, Solar energy storage

CALB

• Key Models: Various
• Applications: EV, Energy Storage

Lishen

• Key Models: 272Ah
• Applications: General Purpose

REPT

• Key Models: 220Ah, 280Ah
• Applications: EV

Comparative Analysis of Popular Brands

Brand Impact

• CATL: ★★★★★
• EVE: ★★★★
• Lishen: ★★★★
• REPT: ★★★★
• CALB: ★★★★

Product Line

• CATL: ★★★★
• EVE: ★★★★★
• Lishen: ★★★
• REPT: ★★★
• CALB: ★★★

Price

• CATL: ★★★★
• EVE: ★★★★
• Lishen: ★★★★★
• REPT: ★★★★★
• CALB: ★★★★★

Supply

• CATL: ★★★★
• EVE: ★★★★★
• Lishen: ★★★★
• REPT: ★★★
• CALB: ★★★

Best Choice for DIY Battery Packs

Considering the availability, brand impact, and product line, EVE's LF280K emerges as the top choice for DIY battery packs. Its deep cycle life of up to 6,000 cycles makes it a reliable and long-lasting option.

Most Cost-Effective Options

As of late 2021 and early 2022, the LF230 from EVE holds the title for the most cost-effective LiFePO4 battery cell, mainly due to supply shortages affecting the prices of other models. It is a strong contender for those seeking a balance between cost and performance.

Final Thoughts

When it comes to selecting the best LiFePO4 battery cell for DIY battery packs, EVE stands out in terms of product variety and availability. Among its models, the LF280K offers the best performance, making it the ideal choice for those who prioritize reliability and lifespan. However, if cost is a significant factor, the LF230 is a valuable alternative.

With this comprehensive guide, you are now equipped to make an informed decision for your next DIY project involving LiFePO4 battery cells.

Confused about inconsistent LiFePO4 battery cell grading? Wondering if Auto Grade or Solar Grade cells are right for you? We're here to cut through the confusion by ditching 'Grade A, B, or C' labels that vary by manufacturer. Our article offers insights into the benefits of our rigorously tested Auto Grade and Solar Grade cells, each designed for specific applications. Learn why our revamped system is the key to simplifying your choices and ensuring you get the right cell for your project.

 

What is an Active Balancer Module?

An Active Balancer Module (Active Balancer) is a unit which will “Actively” balance the voltage between 2 or more cells connected in series.  When charging/discharging cells connected in series, each cell will behave differently depending on their internal resistance which will result in the being unbalanced.  The more you charge/discharge the battery bank, the State of Charge (SOC) and voltage variance between the cells will increase, resulting in 1 cell having a greater SOC, while another cell within the same bank having a lower SOC.  The problem with this is the potential for the cell with the higher SOC being overcharged, while the cell with the lower SOC being over discharged and therefore those cells experiencing a greater derogation in comparison to the other cells.

An Active Balancer will monitor and transfer current between cells within a bank.  Cells with a higher SOC, to cells with a lower SOC ensuring they are better balanced and drastically reducing the chance of one particular cell in the bank being over charged/discharged.

Unlike a passive balancer, an active balancer will operate while a battery bank is being charged, discharged or even left in storage.

What is a Passive Balancer?

Most BMS’s will have a built-in balancing function, however for the majority of BMS’s currently available this will be a Passive Balancer.  A Passive Balancer will attempt to balance cells within a bank by increasing the resistance to cells with a higher voltage/State of Charge (SOC), allowing for more current to flow to cells with a lower voltage/SOC.  A Passive Balancer only works while the bank is being charged, which means cells within a bank can still fall out of balance while being discharged.

 

What is a BMS Parallel Module?

The main purpose of a BMS Parallel Module is to regulate the current flow between 2 or more banks of batteries connected in parallel.

When 2 or more banks of batteries are connected in parallel, the State of Charge (SOC) of the different banks will equalise.  That means, they will transfer current from the highest charged bank to the lowest charged bank until they have the same SOC, and therefore have the same voltage.  With LiFePO4 Cells, this transfer of energy can be significant, and the high current flow will most likely be too great for BMS, while also causing damage the LiFePO4 cells.

The charge profile for LiFePO4 cells is relatively flat, that means there can be a large variance in the SOC between 2 or more cells, with a small variance in their comparative voltages.  For example, you may have only 0.1V difference in voltage between 2 cells, however there will be a big variance in the SOC between these cells.

By using a parallel module, if 2 or more banks are connected in parallel, it will restrict the amount of current transferred between the banks, therefore protecting the BMS and the cells from any potential damage.

Some might say that if you have 2 more bank always connected in parallel then they will always be equalised… Although this might be true in principle, practically there are a couple of scenarios which may see 2 banks attempt to equalise, creating a situation of high current transfer, such as:

1. Before initially connecting banks in parallel, you should need to top balance ALL cells which will ensure they have the same SOC otherwise they will equalise when connected in parallel.
2. If you have 2 banks connected in parallel, 1 bank maybe disconnected by the BMS due to one of the protection parameters (like cell voltage variance) being triggered. If this happens, then one bank will continue to provide/receive current and therefore increasing the variance of the SOC between the banks.  When you attempt to reconnect the bank into the parallel circuit, the banks will attempt to rebalance transferring unrestricted current.

By using a Parallel Module with the BMS for each bank, it will govern the amount of current able to be transferred between cells and avoid any potential damage to the BMS/s or cells.

 

How to connect Batteries in Series?

 

Connecting batteries in Series is when you connect the positive terminal of one battery to the negative terminal of another battery.

Connecting batteries in series will increase the combined Voltage of the packs but the capacity will remain unchanged (or lowest capacity of the combined cells).  For example, if you have 4 x 3.2V (Volt) 200ah (amp hour) batteries connected in series, the total capacity will remain to be 200ah, however the voltage will increase to 12.8 Volts (4 x 3.2V).

When connecting cells/batteries in Series, the capacity of each battery should ideally be the same to ensure that one battery/cell in the circuit is not over charged/discharged.

Unfortunately, the answer to this question is not so simple. There are several variables that determine how many LiFePO4 Batteries/cells you would need to be self-sufficient like:

1. What is your energy consumption (watts)?
2. How long would you like to run off battery power before you needed to recharge?
3. What is the voltage of your inverter?
4. Do you have a charging source like Solar Panels or a Wind Generator?

Calculating your energy consumption

Your energy consumption is the total watts (W) of energy your appliances like a fridge, lights, air-conditioner and even your inverter will consume. The consumption from these appliances will vary as 1) not all of them will be running constantly and 2) appliances like Fridges and air-conditioners will use more, or less energy based on temperature conditions.

There are 2 ways in which I recommend you can calculate your energy consumption:

1. List all your appliances that consume energy, noting what their average rated energy consumption is (you should be able to find this information on its Specification sheet/sticker). Then, list the typical time you would run each appliance. With each appliance, multiply the wattage by the estimated time each appliance would be used for and total them up. Here is an example below:

 

From the example above you can see that we would use 5,400 Watts or 5.4 Kilowatts (kW) in the average day. This also means that our average hourly energy consumption is 225Watts per hour (Wh).

For all of you that are now thinking it’s all too hard and want to know an easier way, then see Option 2 or 3 depending on your situation.

2. Off-Grid for a Caravan, camper, motorhome, or RV, you can buy a Wattmeter from Bunnings, Jaycar, or online for around $20. See image below. A Wattmeter will not only tell you to have much energy you’ve consumed but it will also tell you the peak amps drawn which you will also need to take into consideration for selecting an inverter and wiring sizing which will not be covered by this article.

Plug this unit into a Mains PowerPoint (GPO) at home or in a Caravan Park. (Note: you may need to be a little creative if you have a 15A male plug as most of these Wattmeters will have a 10A female input and the bottom earth pin is larger). Once plugged in, run your appliances as you would in a typical day. After a 24-hour period look at the Wattmeter to see the amount of energy in Watts you’ve used.

If you want to set up an Off-Grid House, then go to your Electricity Box and make a note of the reading on your Electricity Meter (See the image below). In 24 hours take another reading from the meter and take the most recent reading minus the initial meter reading to find the total Watts you’ve used in 1 day.

How many LiFePO4 Batteries do I need?

Now that you know how many Watts of energy you’ve consumed in a day, you will now be able to calculate the Battery Capacity you’ll require to be fully off-grid. In the example above we calculated that we would consume approximately 5.4kW of energy in 1 day. Now the capacity of most batteries is advertised in Amp-hours (ah), so we need to convert Kilowatts (kW) into Amp-hours (ah). To do this you need to know what type of inverter you’ll be running. For those that don’t know, an inverter is a device that converts DC power into AC power. In an effort to keep this simple, we will focus on the input Voltage so we can work out how many batteries you’ll need. For people with a caravan, campervan, motorhome, or RV, you’ll usually go for either a 12 Volt or 24 Volt input, but if you’re looking to run an off-grid house you’ll probably look at a 48 Volt or higher input voltage inverter. So, for this example let’s pretend we’re got a 24 Volt 5 kW Inverter.

Now in the above example we know our daily energy consumption is 5.4kW and we know that our inverter requires 24Volts Input Voltage, so we can then calculate the amount of Amp-hours (ah) of capacity we’ll require to be totally off-Grid for 24 hours. To do this, you simply divide the number of Watts consumed by the input voltage of the inverter. So, in the above example 5400W/24Volts = 225 Amp-hours (ah). So, this means you’d need a minimum of a 225ah LiFePO4 Battery pack @ 24Volts to run your appliances if they consumed 5400 watts each day. Note that this does not take into consideration any solar, wind, or charging input to the battery yet. It is also assuming that you’re using 100% of your storage capacity which is not recommended.

To achieve 225ah of battery capacity at 24 Volts, you will need to connect cells up in series and parallel.

Connecting batteries in Series is when you connect the positive terminal to the negative terminal and so on as shown below. Understand that when you connect cells in series it increases the voltage however it keeps the rated capacity the same (eg 8 x 3.2Volts 206ah cells in series = 25.6Volts with 206ah of capacity).

 

Connecting batteries in Parallel is when you connect each of the cells in a way that all the positive terminals are connected, and all the negative terminals are connected as shown below. Understand that when you connect cells in parallel it increases the rated capacity however it keeps the voltage the same (eg 8 x 3.2Volts 206ah cells in Parallel = 3.2Volts with 1648ah of capacity).

 

 

To achieve 225ah of storage you may connect 16 x 130ah 3.2Volts LiFePO4 cells, you would connect 8 cells in series twice, and then connect them in parallel. This is known as a 2S8P configuration and is illustrated below.

 

If each one of the cells above were 130ah and you connected 16 in a 2S8P configuration, you would have 260ah @ 24Volts or 6.24 Kilowatt-hours (kWh) in storage capacity.

What are the average recharging amps available?

Most people that are looking to be off-grid will have Solar as a recharging source, however, you can also consider Wind or even a fuel-powered generator (however I personally would only use a generator as a last resort as it’s not free to power).

Solar can be good however depending on where you live, it can be limited to the number of hours in the day you have to be able to recharge your battery bank, and depending on your energy consumption and storage capacity, you may need a large surface area to be able to generate enough energy to recharge your battery bank.

Wind turbines can also be a great means of recharging your batteries, it’s not really limited to particular hours of the day, however, you obviously need to have wind for it to be useful.

Regardless of if you choose solar, wind, or a fuel generator, you should now consider what recharging amps will be available when considering how many LiFePO4 Batteries you’ll need to be off-grid.

In the example above we know we need 225ah @ 24Volts to be able to run our appliances with our 24Volts 5kw inverter for a 24-hour period. However, let’s now consider that we have some solar panels which can recharge our batteries during the day. Again, to try and keep this simple, let’s pretend that we have solar panels that can generate on average 30amps @ 24Volts of charging current 8 hours per day. This means that in the 8 hours period we would be able to recharge our batteries with 240amps.

Now because we are now generating power to recharge our batteries for an average of 8 hours per day, it means that during the day we are not using the stored battery power. As such, the 225ah of storage capacity required to be Off-Grid for a 24-hour period can now be reduced. If we are generating solar power for 8 hours per day, then it means that we need to run off batteries for the other 16 hours. So this means that we would now only need 3600W (16 hours x 225Wh) of storage capacity rather than the 5400W initially calculated. It also means that we can reduce our battery bank down to 150ah of storage capacity.

As a rule of thumb, it’s recommended that you don’t use more than 80% of your LifePO4 Cells capacity, so 195ah would be enough capacity to run off Grid for 24 hours while recharging the LiFePO4 cells during the day.As such, our 24Volts 230ah Battery Kit would be a perfect fit for this setup which can be seen here:
https://lifepo4oz.com/collections/lifepo4-battery-kits/products/24v-eve-230ah-5-89kwh-lifepo4-battery-pack-kit-with-smart-bms

 

LiFePO4 Off Grid Solar System Small Home
Welcome to LiFePO4 Oz, Australia's trusted name for off-grid battery storage system solutions. Our experienced team is here to help you take charge by finding the off-grid solar batteries system for your needs. Here we are providing smart, high-quality, and reliable energy storage solutions for Australians.

Our passion for helping people to store energy and save money while also preserving the environment drives us to originate and distribute emerging products. We can achieve this by helping people build their own lithium Off grid batteries banks with LiFePO4 Batteries and accessories.

Which Off Grid Solar System Is Right For You?

There are so many options for off-grid battery systems, solar batteries, power, and storage. Choosing the right off-grid solar system for you will depend on your energy consumption, location, and period that you're looking to operate before needing to charge.

Why choose a LiFePO4 Oz Off Grid Battery System?

Plenty of Australian homeowners dream about going with an off-grid solar battery systems and home battery storage. So we are providing the best off-grid products discovered by our experienced team. Our Off-grid solar battery systems are compatible to work with roof- or ground-mounted solar panels, an MPPT solar charge controller, an Inverter/Charger and an integrated diesel generator for backup, if required.

LiFePO4 10kw Off Grid Solar System Price Australia - LiFePO4 Oz

One thing that we have not talked about here, that is cost. Although, 10kW off grid solar system price will be between $10,000 and $15,000. The lithium off grid solar power batteries will be a bit more expensive. Additionally, there are many things that homeowners thinking about going off-grid should take into consideration.

Benefits of an Off-Grid Solar Power System
1. Avoiding Power Outages
2. Reducing Electricity Costs
3. Easier Installation
4. Suitable for Remote areas that do not have Grid power access.
5. Keeping the Environment Clean and Green

You can view our Off- Grid Battery Kits here: LiFePO4 Battery Kits

Alternatively, if you are considering a lifepo4 off grid solar batteries system and want to know if it is right for you, then call us for advice. We will be able to assist you in choosing the right solar system as per your requirements. Our mission is to find exciting ways to extend the use of off-grid solar solutions to power our everyday lives.