10 Things to Consider When Buying lifepo4 battery solar system

LiFePO4 battery is the best you can buy among any deep cycle batteries. However, there are countless options, even among LiFePO4 batteries. These batteries come in different voltages, ampere-hour ratings, features, and many other parameters. Therefore, you need to know how to choose a lifepo4 battery to buy the right one.

OMMO Product Page

This article will provide all the information you need on the subject. You will know about all the factors that play a role in buying decisions. You will also learn about the best places to get these batteries.

What is a LiFePO4 Battery?

LiFePO4 battery stands for Lithium Iron Phosphate batteries. They are named so because the cathode material is LiFePO4. The anode is made of graphite. LiFePO4 batteries are a considerable improvement over conventional lithium-ion batteries. Additionally, their performance is leaps and bounds ahead of lead-acid batteries. These reasons have made LiFePO4 the most popular battery choice in recent years.

Factors to Consider When Buying LiFePO4 Battery

Different users will have different preferences when buying a LiFePO4 battery. Your decision should be based on factors like:

Capacity

The capacity of a battery represents how many appliances it can power and for how long. It is measured in Watt hours (Wh). The capacity is the primary factor to consider and the main factor that drives up the LiFePO4 battery cost.

Users often get confused when they cannot see a Wh rating mentioned on the battery. Instead, they find voltage and Amp hours (Ah) ratings.

That is alright. You can find the Wh rating by multiplying voltage and amp hours.

Wh = V x Ah

For a 12V battery with a 320 Ah rating, the Wh will be:

Wh = 12 x 320 = Wh

To find out how much capacity you need, you can add the wattage of all the appliances you use. Then you can multiply it by the hours you want to run them without charging the battery. This will give you the minimum watt hours of the lithium-ion batteries you should buy.

For instance, if you want to run a total of 300W load for 10 hours, you require a minimum of:

Minimum Wh = 300 x 10 = Wh

Since the load or running time can increase or decrease, the required battery should have more capacity than the minimum Watt hours you require. Therefore, the Wh battery will be a good fit for the Wh minimum capacity.

Value For Money

Many users focus on &#;price&#; as the deciding factor. However, a better factor to consider should be the value for money of the battery.

Lead acid batteries are the cheaper option in the market today. However, their lifespan is only one-tenth that of a LiFePO4 battery. While LiFePO4 batteries can last over 10 years, a lead acid battery will run out after a year or so. Additionally, there is always the risk of cheaper batteries running out while on the job.

Therefore, opt for value for money instead of the price as the deciding factor. It can save you countless trouble in the long run. This brings us to our next important criterion.

Battery Life

It is essential to consider how many years a battery will last. You can save money and buy lead-acid batteries if you want a short fix for a few months. However, most users do not want that. Instead, they require a long-term solution.

A LiFePO4 battery is the best option in terms of battery life. A good quality LiFePO4 battery will easily last upward of 10 years. AGM and conventional lithium-ion batteries can work well for three to four years.

Cycle Life

Cycle life means the number of charge and discharge cycle that your battery can undergo. A longer cycle life means a battery will last longer. Batteries do not come with a suggestive lifespan on the box. However, they do mention a cycle life. Choose an option with a longer cycle life for a better return on investment.

Warranty

Warranty is a good indicator of the build quality of the battery and its lifespan. Lead acid batteries come with a 6-month warranty. Therefore, they are workable for up to a year until they demand replacement. LiFePO4 battery is a whole different game.

You will find different kinds of warranty periods with different LiFePO4 manufacturers. Eco Tree Lithium is the leader in the game as it provides a warranty of an astonishing 6-year. You can expect the Eco Tree Lithium batteries to easily work for over 10 years with a warranty like that.

Depth of Discharge (DoD)

Depth of Discharge (DoD) is a significant factor that makes people switch from existing lead acid batteries to lithium iron phosphate batteries. Depth of discharge denotes the usable capacity of the battery.

For instance, the depth of discharge for lead acid batteries is 50%. Therefore, you can use these batteries to 50% of their capacity. After that, they will require charging. However, for Eco Tree Lithium&#;s LiFePO4 battery, the DoD is a whopping 100%. You can use LiFePO4 through the full rated capacity.

Here is an example for putting things in perspective. Suppose your capacity requirement is 200 Ah. You can meet this requirement with a 200 Ah LiFePO4 battery. However, you will need a 400 Ah battery capacity if opting for a lead acid battery due to its half depth of discharge.

Maintenance Requirements

Every battery has a distinct maintenance requirement. Lead acid batteries have many requirements like electrolyte top-ups and venting the buildup gases. Fortunately, maintenance of LiFePO4 battery is much simpler and easy.

Dimensions

Battery dimensions are important for applications like motorhomes. The battery compartments can accommodate a particular size battery bank. LiFePO4 battery has prefixed size groups to denote the standard size of the battery. Match the lithium battery group with your requirement.

Weight

Weight is not always on the priority list of important parameters. However, some users find having a lighter battery preferable. If that is the case, any lithium battery is a better buy over a lead acid battery. For instance, a lead acid battery pack of 500 Ah can weigh around 850 kg. The same job can be done by a 250 Ah lithium-ion battery weighing 210 kg. This means a considerable difference in weight.

The main differences come from the eliminated weight of lead plates and electrolytes. Additionally, lithium iron phosphate batteries have lighter electrodes.

Safety

Safety becomes essential when you operate your battery near life and property. There have been instances where lead acid battery leak fluids that cause corrosion of the battery and nearby appliances. Conventional lithium batteries have fire and explosion hazards with them. However, lithium iron phosphate batteries are made using very stable compounds of iron and phosphate. These will never explode or cause fire injury.

Voltage Rating

The voltage of the battery pack is important because it determines its usability. For instance, you cannot replace a 24V battery with a 48V battery and vice versa. Every type of voltage rating has a distinct application, advantage, and disadvantage. If you are replacing your old batteries, you will need to find old voltage rating and match new batteries with the same rating for a constant voltage.

Common voltage ratings are:

• 12V: Ideal for powering lights, science projects, and small-scale energy storage.
• 24V: Used for trolling motor, solar panels in motorhome, and electric scooters.
• 48V: Used for home solar batteries, data backups, motorhomes, etc.

Cold Weather Usage

All batteries are known for performance stuttering in extreme temperatures. Freezing conditions can lead to battering running flat. These batteries often do not recover once the temperature toll takes place. Therefore, find the optimal temperature range of the battery. Better yet, choose Eco Tree Lithium batteries with an inbuilt heater for cold weather.

Features

Modern batteries come with many features that add to the convenient user experience. Take the case of this battery. It has a Bluetooth feature to check your battery stats remotely. You do not have to open the battery compartment. You don&#;t have to use a multimeter to check the voltage and current parameters. You can manage the battery remotely from a Bluetooth device.

Other secondary features can include LED indicators for the charging system. Having a handle to transport the battery is also a handy feature to have.

Battery Management System (BMS)

Always choose a LiFePO4 battery that comes with a BMS. A battery management system has a lot of safety protocols against potential hazards. All batteries are prone to irreversible overcharge and over-discharge damage. BMS protection measures cut off the circuit to eliminate any possibility of damage.

Environmental Impact

Modern energy technologies are pushing towards greener initiatives. It is recommended to choose an environmentally friendly battery option. For instance, cobalt-based batteries (like lithium cobalt oxide) are not environmentally friendly. This is because cobalt is rare and toxic in nature. LiFePO4 battery is one of the greenest battery out there.

Toxic

Cobalt and lead come in toxic heavy metals category. These materials can cause health hazards if they come into human contact. Therefore, batteries that include these metals are considered unsafe. This includes all lead batteries. However, a lithium iron phosphate battery does not have any toxic substances in them.

Additionally, lead acid chemistry leads to the emission of toxic gases. You might be familiar with the pungent smell that often comes from lead batteries. Therefore, choose a battery that does not have any such risk. You will never need to vent lithium iron batteries because it releases no toxic gases.

Do You Need BMS in a LiFePO4 Battery?

Yes, you should always buy a LiFePO4 battery with a BMS. Lithium iron phosphate battery is a hefty investment. A BMS protects that investment from any harm. BMS will prolong the life of your battery significantly by monitoring every parameter.

Battery management systems come with surge protectors to avoid the harm of excessive currents. Additionally, many other circuits shield the battery from adverse situations. Many BMS also come with displays and relays that monitor data.

Where to Buy a LiFePO4 Battery?

Eco Tree Lithium is the best place to buy a lithium iron phosphate battery. These batteries outperform most batteries on the market. They have features like BMS, Bluetooth, an in-built heater, and a 6-year warranty. Additionally, you get the brand name of the leading LiFePO4 battery supplier globally.

Conclusion

You can easily choose the best battery with the above information. You can also differentiate between LiFePO4 and other lithium-ion batteries. A good battery can be the driving point for a decade of worry-free operation. A lousy option can lead to hazards, breakdowns, and chasing the manufacturer for a replacement. Therefore, spend extra time choosing the battery to avoid wasting your time later.

Frequently Asked Questions (FAQs)

Here are the answers to some common questions regarding LiFePO4 batteries:

Are all LiFePO4 batteries the same?

No, all LiFePO4 batteries are not the same. The build quality of the batteries differs between manufacturers. These batteries also come in many different types, dimensions, capacity, voltage rating, and features.

What are LiFePO4 Batteries?

LiFePO4 batteries are a type of lithium battery built from lithium iron phosphate. Other batteries in the lithium category include:

• Lithium Cobalt Oxide (LiCoO22)
• Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2)
• Lithium Titanate (LTO)
• Lithium Manganese Oxide (LiMn2O4)
• Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2)

LiFePO4 vs. Lithium Ion Batteries

Now that we know what LiFePO4 batteries are, let&#;s discuss what makes LiFePO4 better than lithium ion and other lithium batteries.

The LiFePO4 battery isn&#;t great for wearable devices like watches. Because they have a lower energy density compared to other lithium-ion batteries. That said, for things like solar energy systems, RVs, golf carts, bass boats, and electric motorcycles, it&#;s the best by far. Why?

Well, for one, the cycle life of a LiFePO4 battery is over 4x that of other lithium ion batteries.

It&#;s also the safest lithium battery type on the market, safer than lithiom ion and other battery types.

And last but not least, LiFePO4 batteries can not only reach 3,000-5,000 cycles or more&#; They can reach 100% depth of discharge (DOD). Why does that matter? Because that means, with LiFePO4 (unlike other batteries) you don&#;t have to worry about over discharging your battery.

A LiFePO4 Battery for Every Application

LiFePO4 technology has proven beneficial for a wide variety of applications. Here&#;s a few of them:

• Fishing boats and kayaks: Less charging time and longer runtime means more time out on the water. Less weight allows for easy maneuvering and a speed boost during that high-stakes fishing competition.
• Mopeds and mobility scooters: No dead weight to slow you down. Charge to less than full capacity for impromptu trips without damaging your battery.
• Solar setups: Haul lightweight LiFePO4 batteries wherever life takes you (even if it&#;s up a mountain and far from the grid) and harness the power of the sun.
• Commercial use: These batteries are the safest, toughest lithium batteries out there. So they&#;re great for industrial applications like floor machines, liftgates, and more.
• Much more: In addition, lithium iron phosphate batteries power many other things. For example &#; flashlights, electronic cigarettes, radio equipment, emergency lighting and much more.

Is LiFePO4 better than lithium ion?

The LiFePO4 battery has the edge over lithium ion, both in terms of cycle life (it lasts 4-5x longer), and safety. This is a key advantage because lithium ion batteries can overheat and even catch fire, while LiFePO4 does not.

Is LiFePO4 more dangerous than AGM or lead acid?

Nope. It&#;s actually quite a bit safer. And for a number of reasons, including the fact that LiFePO4 batteries don&#;t leak toxic fumes. And they don&#;t spill sulfuric acid like many other batteries (like lead acid.) And like we mentioned earlier, they don&#;t overheat or catch fire.

What is the life expectancy of LiFePO4 batteries?

Life expectancy is one of the biggest perks, if not the biggest perk of LiFePO4. Our lithium batteries are rated to last around 5,000 cycles. That is, 10 years or so (and often more), depending on usage of course.

Even after those 5,000 cycles, our LiFePO4 batteries can still function at 70% capacity. And better still, you can discharge past 80% without a single issue. (Lead acid batteries tend to gas out when discharged past 50%.)

The company is the world’s best lifepo4 battery solar system supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

Here are lithium iron phosphate (LiFePO4) battery voltage charts showing state of charge based on voltage for 12V, 24V and 48V LiFePO4 batteries &#; as well as 3.2V LiFePO4 cells.

Note: The numbers in these charts are all based on the open circuit voltage (Voc) of a single battery at rest. If your LFP battery manual has its own discharge curve and charging parameters, they should take precedence over the ones below.

12V LiFePO4 Battery Voltage Chart

Here&#;s a printable version of the above chart:

And here it is graphed out:

12V 100Ah LiFePO4 batteries are currently some of the most popular for off-grid solar power systems. They&#;re a drop-in replacement for 12V lead acid batteries, and a great upgrade.

They are fully charged at 14.6 volts and fully discharged at 10 volts. They are made by wiring four 3.2V LiFePO4 cells in series.

12V LiFePO4 Battery Charging Parameters

• Charging voltage: 14.2-14.6V
• Float voltage: 13.6V (or disabled)
• Maximum voltage: 14.6V
• Minimum voltage: 10V
• Nominal voltage: 12V or 12.8V

24V LiFePO4 Battery Voltage Chart

Here&#;s a printable version of the above chart:

And here it is graphed out:

24V lithium iron phosphate batteries are another popular option for DIY solar power projects. You can either buy a 24V LiFePO4 battery off the shelf, or get two identical 12V LiFePO4 batteries and connect them in series to make a 24V battery bank.

They are fully charged at 29.2 volts and fully discharged at 20 volts. They are made by connecting eight 3.2V LiFePO4 cells in series.

24V LiFePO4 Battery Charging Parameters

• Charging voltage: 28.4-29.2V
• Float voltage: 27.2V (or disabled)
• Maximum voltage: 29.2V
• Minimum voltage: 20V
• Nominal voltage: 24V or 25.6V

48V LiFePO4 Battery Voltage Chart

Here&#;s a printable version of the above chart:

And here it is graphed out:

48V batteries are more popular for larger solar systems. They rarely make sense for small-scale projects. Designing a higher voltage solar system allows you to keep amperage low, thereby saving you money on wiring and equipment costs.

48V LiFePO4 batteries are fully charged at 58.4 volts and fully discharged at 40 volts. They are made by connecting 16 3.2V LiFePO4 cells in series.

48V LiFePO4 Battery Charging Parameters

• Charging voltage: 56.8-58.4V
• Float voltage: 54.4V (or disabled)
• Maximum voltage: 58.4V
• Minimum voltage: 40V
• Nominal voltage: 48V or 51.2V

3.2V LiFePO4 Cell Voltage Chart

Here&#;s a printable version of the above chart:

And here it is graphed out:

Individual LiFePO4 cells have a nominal voltage of 3.2 volts. They are fully charged at 3.65 volts and fully discharged at 2.5 volts.

You can buy individual LiFePO4 battery cells online. They&#;re best used for making your own lithium batteries. You can wire cells in series and parallel to make LFP batteries with your desired voltage and capacity combinations.

3.2V LiFePO4 Cell Charging Parameters

• Charging voltage: 3.55-3.65V
• Float voltage: 3.4V (or disabled)
• Maximum voltage: 3.65V
• Minimum voltage: 2.5V
• Nominal voltage: 3.2V

3 Ways to Check LiFePO4 Battery Capacity

1. Measure Battery Open Circuit Voltage with a Multimeter

Pros: Moderately accurate

Cons: Must disconnect all loads and chargers and let battery rest

A battery&#;s voltage changes depending on its charge and discharge rate. Plus, LiFePO4 batteries have a relatively flat discharge curve from around 99% to 20% capacity. Because of these factors, it can be hard to estimate their state of charge from voltage alone.

To get an even somewhat accurate estimate of LiFePO4 battery capacity based on voltage, you first need to disconnect any loads and chargers from the battery. (Don&#;t forget to disconnect your solar panels from your charge controller first!)

Let the battery rest for a little while &#; I usually wait 15-30 minutes &#; and then measure its open circuit voltage with a multimeter.

Compare your measurement to the right voltage curve above, or the state of charge chart in your battery manual. Use it to get a rough estimate of your battery&#;s remaining capacity.

For example, I own the Bravabattery 12V 150Ah LiFePO4 Deep Cycle Battery . I wanted to check its capacity after having stored it for a few weeks. I brought it out of storage and measured its voltage with a multimeter. I got 13.23 volts.

I then compared this number to the 12V LiFePO4 state of charge chart above, as well as the one in the battery manual.

Based on the charts, I&#;d estimate my battery&#;s state of charge was somewhere around 80%.

I like this method best for estimating the state of charge of an LFP battery I&#;ve just received or just pulled out of storage. The battery is already at rest and not connected to anything. I find it too inconvenient to disconnect everything once the battery is in use.

2. Use a Battery Monitor

Pros: Most accurate, convenient

Cons: Good battery monitors are expensive

The best way to track battery capacity is to connect a good battery monitor &#; such as the Victron SmartShunt or Victron BMV-712.

Battery monitors track the amount of amp hours consumed to accurately estimate the state of charge. They also display useful system specs such as battery voltage and current. Some connect via Bluetooth to your so you can check your LiFePO4 battery&#;s capacity in a mobile app.

3. Use a Solar Charge Controller

Pros: Convenient

Cons: Inaccurate

If you charge your LiFePO4 battery with solar panels, you may be thinking:

&#;My solar charge controller already measures battery voltage. I can just use it to check battery capacity.&#;

But!

This voltage reading is largely inaccurate. It suffers from all of the problems mentioned above, plus it&#;s done while the battery is connected to loads and chargers.

(Not to mention that some charge controllers have incorrect voltage readings.)

For example, recall that when I checked my battery&#;s voltage with a multimeter at the battery terminals, I got a voltage reading of 13.23 volts. That correlates to a roughly 80% state of charge.

But when I connected my battery to an MPPT charge controller, the controller measured 13.0 volts. That correlates to a roughly 30% state of charge &#; a difference of 50%! Granted, some charge controllers have much more accurate battery voltage readings than others.

After all, voltage drops under load. And a charge controller is a load. If I were to connect a solar panel and start solar charging the battery, its voltage would quickly jump.

Checking battery capacity this way is convenient. But beware that it can be quite inaccurate. I generally use this voltage reading just to make sure my battery isn&#;t close to being fully discharged.

If you use this method and want to make sure it&#;s as accurate as possible, you can buy a battery voltage sensor.  A voltage sensor gives the controller a more accurate voltage reading, especially in solar power systems with long wire runs.

LiFePO4 Voltage FAQ

What is the voltage of a fully charged 12V LiFePO4 battery?

A fully charged 12V LiFePO4 battery will have a charging voltage of around 14.6 volts and a resting voltage of around 13.6 volts.

What is the charging voltage of a 12V LiFePO4 battery?

The charging voltage for 12V LiFePO4 batteries is 14.2 to 14.6 volts. This works out to a charging voltage of 3.55 to 3.65 volts per cell.

Most often, you&#;ll see LiFePO4 battery chargers and solar charge controllers use a charging voltage of 14.4 volts for 12V lithium batteries.

What is the minimum voltage of a 12V LiFePO4 battery?

The minimum voltage of many 12V LiFePO4 batteries is around 10 volts. The battery&#;s BMS should detect when the battery voltage falls to around 10 volts and trigger low-voltage cutoff. (Low-voltage cutoff is also called low-voltage disconnect, which you&#;ll sometimes see abbreviated LVD.)

Note: Some batteries have higher cutoff voltages, such as 10.6V. So the limit in your battery manual may not be exactly 10V.

LiFePO4 batteries in low-voltage cutoff enter a sleep mode to protect the battery cells from over discharge. LFP batteries in sleep mode can have very low voltage readings, usually less than 5 volts. You may think that the battery is dead, but really it&#;s just sleeping.

Once a battery enters sleep mode, it needs to be woken up. Refer to your battery manual for instructions on how to do this. If your manual doesn&#;t have instructions, check out our tutorial on how to wake up a sleeping LiFePO4 battery.

What is the float voltage of a 12V LiFePO4 battery?

LiFePO4 batteries don&#;t need to be float charged because they don&#;t leak charge the way lead acid batteries do.

If you can, disable float charging on your charge controller or battery charger. If you can&#;t, prevent the battery from entering float charge by setting the float voltage to that recommended in the battery manual &#; usually 13.6 volts ± 0.2 volts.

How much can you discharge a LiFePO4 battery?

Many LiFePO4 batteries can discharge 100% of their rated capacity every time with no ill effects.

However, many manufacturers recommend discharging only 80% to maximize battery life. In fact, some brands state the cycle life of their batteries based on 80% depth of discharge (DoD).

If you are looking for more details, kindly visit Balcony Solar System.