If you want to extend the lifespan of your LiFePO4 battery while maintaining its performance, understanding the best way to charge it will be very helpful. There are several lithium battery chemistries available in the market, but LiFePO4 is undoubtedly the best one so far, especially for applications that require large battery packs.
Due to its extremely stable chemical properties, lithium deep cycle battery provides a safer option than other lithium technologies, which may cause fire hazards if mishandled. LiFePO4 batteries are also more durable and capable of withstanding electrical and thermal abuse conditions. This means they can withstand time and undergo numerous cycles without compromising performance. Although LiFePO4 batteries are more expensive than lithium or lead-acid batteries, they make a good long-term investment if properly maintained, which is a crucial condition. This article will provide you with the four best methods to charge a LiFePO4 battery, which will help those who want to fully utilize their battery system and make it a valuable investment.
Do LiFePO4 Batteries Need A Special Charger?
It is a very common question when people consider switching to lithium iron phosphate batteries. The short answer is no - a special charger is not necessary. However, what is required is a charger that provides the appropriate charging specifications for the battery.
What Charger Should I Use For LiFePO4 Battery?
If you have to charge a deep cycle battery 12v, you can use a charger with 14V to 14.6V. The charger within this voltage range can effectively assess your LiFePO4 battery. But, it does not mean you use a charger to charge other lithium batteries.
What Are The Charging Specifications Of A LiFePO4 Battery?
Compared to other lithium-ion batteries, lithium iron phosphate batteries have different charging specifications. Here are some general charging specifications for lithium iron phosphate batteries:
Charging Voltage
It is recommended to charge lithium iron phosphate batteries between 3.6V and 3.8V per cell. For example, if you have a 4-cell lithium iron phosphate battery, the charging voltage range is 14.4V to 15.2V.
Charging Current
It is recommended to charge lithium iron phosphate batteries with a charging current between 0.5C and 1C (C is the battery capacity). For example, if you have a 100 amp hour lithium battery, the recommended charging current will be between 50A and 100A.
Charging Temperature
The best charging temperature for lithium iron phosphate batteries is between 0°C and 45°C. Charging outside of this range will affect the battery's performance and lifespan.
Charging Method
Lithium iron phosphate batteries should be charged using a constant current (CC) and constant voltage (CV) method. This means that the charging current remains constant until the battery reaches a specific voltage, and then the voltage remains constant until the charging current drops to a certain level.
To ensure proper charging of LiFePO4 batteries, it is important to follow the voltage specifications provided by the battery manufacturer. The table below shows the charging parameters that are usually recommended for LiFePO4 batteries.
| System Voltage | Charging Parameters |
|---|---|
| 12V | 14V – 14.6V |
| 24V | 28V – 28.6V |
| 36V | 42V – 42.8V |
| 48V | 56V – 57.8V |
This chart shows that you can use any type of charging equipment to charge your 12V lithium iron phosphate battery as long as the charging voltage is within the range of 14V to 14.6V. However, just because you can, doesn't mean you should. Therefore, we will introduce the four best ways to charge your lithium iron phosphate battery.
4 Best Ways To Charge A LiFePO4 Battery
1. Chargers using lithium iron phosphate
Diypow recommends that you choose a charger that is designed for your battery chemistry. This means that we recommend using a lithium charger, like the Diypow lifepo4 battery charger, when charging lithium batteries.
Upon viewing the chart, you will see that there are two stages:
Stage 1, "Bulk" - Provide a constant charging current to the battery while gradually increasing the voltage. This stage typically takes 1 to 2 hours.
Stage 2, "Absorption" - When the charging voltage reaches slightly over 14V, the LiFePO4 battery's charging state is around 90%. At this point, to achieve a full charge, the charging voltage becomes constant, and the charging current decreases to around 5% to 10% of the battery's rated capacity.
2. Using A Lead-acid Battery Charger To Charge Lifepo4 Battery
So you're thinking of replacing your deep cycle lead-acid battery with a brand new lithium iron phosphate battery (a smart move) and you're wondering if you need a new charger?
Good news - not necessarily! Most lead-acid battery chargers will work just fine.
It is possible to charge these batteries with a lead-acid battery charger as long as the charge settings are within the acceptable parameters for LiFePO4 batteries. Because AGM and Gel lead-acid batteries and LiFePO4 batteries have similar voltage ratings, AGM and Gel charging algorithms can usually meet the charging voltage requirements of LiFePO4 batteries. An important difference between these batteries is that, unlike lead-acid batteries, LiFePO4 batteries do not lose their charge as quickly when disconnected. This means that float charging is not necessary. Therefore, the float charging option should be switched off when charging with a lead-acid battery charger. If this is not possible, the float charge voltage should be set low enough so that it is never reached. Setting the float charge voltage to below 13.6V is sufficient. In addition, LiFePO4 batteries do not require balancing or temperature compensation. It is therefore also necessary to disable these functions. If it is not possible to make these necessary adjustments to the lead-acid battery charger, it is highly recommended to purchase a suitable LiFePO4 charger.
3. Using Solar Panels To Charge Lifepo4 Battery
The use of solar cells to charge LiFePO4 batteries is becoming very popular because the energy stored does not only come from other energy sources but is actually generated by the solar panels. (lithium solar batteries) Whether at home, on a boat, or in a caravan, the solar system looks pretty much the same (as shown in the picture below).
- Determine battery capacity and charging requirements: Check the battery datasheet to understand its capacity and charging specifications such as maximum charging current and voltage.
- Choose a solar panel: Select a solar panel that can provide enough power to charge the battery. The solar panel's output voltage should be higher than the battery voltage for efficient charging.
- Choose a charging controller: A charging controller regulates the charging process to prevent overcharging, which can damage the battery. Choose a charging controller that is compatible with LiFePO4 batteries and can handle the maximum power output of the solar panel.
- Connect the solar panel to the charging controller: Connect the positive and negative terminals of the solar panel to the input terminals of the charging controller.
- Connect the charging controller to the battery: Connect the positive and negative terminals of the charging controller to the battery terminals.
- Set charging parameters: Set the charging parameters of the charging controller according to the battery specifications. For LiFePO4 batteries, the charging voltage per cell should be around 3.6-3.7 volts, and the charging current should not exceed the maximum charging current of the battery.
- Monitor the charging process: Monitor the charging process to ensure the battery is charging correctly. Check the battery voltage and temperature regularly to ensure it is not overheating or overcharging.
- Disconnect the solar panel connection: Once the battery is fully charged, disconnect the solar panel from the charging controller to prevent overcharging.
By following these steps, you can safely and efficiently charge a LiFePO4 battery with a solar panel.
4. Using Alternators (and Dc-dc Chargers) To Charge Lifepo4 Battery
Last but not least, another good way to charge lithium iron phosphate batteries is to use an AC generator. This is the best RV battery and best battery for trolling motor that have battery storage systems.
What Is An Alternator?
An alternator is a type of generator that converts mechanical energy into electrical energy. It produces alternating current (hence the name), which is then converted into direct current through a rectifier connected to the alternator. This device is an important component of the electrical system of every internal combustion engine vehicle. It charges the starter battery and is used to start the vehicle's engine. With some adjustments, you can use this electrical system while driving the vehicle to charge your battery pack (in this case, a lithium iron phosphate battery).
Can LiFePO4 Be Charged From The Alternator?
Yes, LiFePO4 batteries can be charged from an alternator. However, it is important to ensure that the alternator is properly regulated to prevent overcharging or undercharging the battery, which could potentially damage it.
What Are The Charging Guidelines For LiFePO4?
Diypow LiFePO4 batteries can be safely charged at temperatures ranging from 0°C to 55°C (or -4°F to 131°F), but we recommend charging at temperatures above 0°C (or 32°F). If you charge the battery at temperatures below freezing, you must ensure that the charging current is between 5-10% of the battery capacity.
How To Charge A LiFePO4 Battery?
The ideal method for charging a lithium iron phosphate battery is to use a lithium iron phosphate battery charger, as the charger is programmed to limit the voltage appropriately. Wet lead-acid battery chargers often have higher voltage limits, which can cause the battery management system (BMS) to enter protection mode and may result in fault codes being displayed by the charger.
Charging Batteries in Parallel
When paralleling lithium batteries, it's best to charge each battery individually before paralleling them. If you're charging a 12V LiFePO4 battery, the charging voltage should be between 14V-14.2V. Meanwhile, charging a 36V lithium battery requires a voltage of 42V-42.6V. If you have a voltmeter, check the voltage after a few hours of charging, and make sure they're within 50mV (0.05V) of each other before paralleling. This will minimize the chance of battery imbalance and maximize the system's performance. Over time, if you notice a decrease in the battery pack's capacity, disconnect the parallel connection and charge each battery individually before reconnecting.
Charging Batteries in Series
Connecting lithium batteries in series is similar to connecting them in parallel. Before connecting them in series, it's best to charge each battery separately and check the voltage to ensure that their voltages are within 50mV (0.05V) of each other. It's highly recommended to use multiple chargers connected in series to charge the lithium batteries. This means that each battery is charged at the same time but completely independently of the others. In some applications, this may not be practical, which is why Diypow offers 24V and 48V batteries to reduce the need for multiple batteries to be connected in series.
How To Store Lithium Iron Phosphate Batteries?
Lithium iron phosphate batteries are easier to store than lead-acid batteries. For short-term storage of 3-6 months, you don't need to do anything special. Ideally, keep them at a 50% charge before storage. For long-term storage, it's best to store them at a 50% charge and then cycle them by discharging, charging, and then partially discharging to around 50% every 6-12 months.
FAQs
What is the best voltage to charge a LiFePO4 battery?
LiFePO4 battery requires only 2 steps, charge voltage is recommended to be set to 14.40V (3.60V per cell).
Do LiFePO4 batteries need a special charger?
Yes, LiFePO4 batteries do require a special charger designed for this type of battery chemistry. Using a charger that is not specifically designed for LiFePO4 batteries can result in overcharging or undercharging, which can damage the battery or reduce its lifespan. Therefore, it is important to use a charger that is compatible with LiFePO4 batteries to ensure their safe and efficient charging.
Is it OK to charge LiFePO4 to 100%?
Unlike lead-acid batteries, lithium batteries do not require float charging. For long-term storage applications, lithium batteries should not be stored at 100% state of charge (SoC), so it is recommended to perform a full cycle (charge and discharge) every 6-12 months, and then store them at a 50% SoC.
How do you prolong the life of a LiFePO4 battery?
For optimum performance and life, Lifepo4 batteries should be charged and discharged within the appropriate voltage range and not overcharged or deeply discharged. Overcharging or deep discharging may result in damage to the battery and shorten its life.
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.
What voltage is 100Ah LiFePO4 full charge?
14.6 volts
What is the best charging current for LiFePO4 battery?
A recommended charging current no greater than 0.5C will help to maximize the lifespan of the LifePO4 battery.
