After purchasing a LiFePO4 battery, is it still necessary to buy a customized LiFePO4 charger? Are the LiFePO4 claims on the market a scam? First of all, it is important to understand that although LiFePO4 batteries have many advantages over traditional lead-acid batteries, they have different charging requirements. In this article, we will explore whether it is possible to charge LiFePO4 with a regular charger and what you need to consider to answer your questions.

Contents

• Can you charge LiFePO4 with a normal charger?
  
• Can you charge LiFePO4 with an AGM charger?
  
• LiFePO4 and lead-acid battery charging curve
  
• Charge LiFePO4 correctly with LiFePO4 chargers
  
• Conclusion
  
• FAQs

Can you charge LiFePO4 with a normal charger?

Can you charge LiFePO4 with a normal charger? It is generally not recommended. It may not be fully charged and may affect the performance and lifespan of lithium iron phosphate batteries or even pose a safety risk. Therefore, it is recommended to use a special LiFePO4 charger to charge LiFePO4 batteries. Below I will explain the reasons for this, starting from how the LiFePO4 battery works:

1. Charging voltage: A fully charged 12V lithium iron phosphate battery should have a voltage of around 13.3-13.4V, while a fully charged lead-acid battery has a voltage of around 12.6-12.7V. At 20% capacity, a lithium battery has a voltage of around 13V, while a lead-acid battery reaches around 11.8V. The voltage difference between a lithium battery and a lead-acid battery is relatively small and can be less than 0.5V at 80% capacity.
2. Charging profile: LiFePO4 batteries require a special charging profile that consists of a constant current and constant voltage charge. Normal chargers, especially those for lead-acid batteries, usually use a simpler charging profile that is not suitable for lithium-ion batteries.
3. Safety: Although LiFePO4 batteries are safer than many other lithium batteries, improper charging can still lead to overheating or even fire if the battery is not charged correctly.

Can you charge LiFePO4 with AGM charger?

AGM batteries are a type of lead-acid battery that requires a specially designed charger because they require more precise battery management to avoid overcharging or undercharging. Although LiFePO4 batteries can be easily charged using the simplest AGM charger curve, they cannot be fully charged and long-term use of the AGM charger will damage the battery's lifespan.

If it is only needed for emergency use, the AGM charger can meet the basic charging requirements, but for the health and safety of the battery, it is recommended to use a dedicated LiFePO4 charger.

LiFePO4 and lead-acid battery charging curve

To help you better understand why LiFePO4 cannot be used with a regular charger (i.e. mainly a lead-acid charger), let's visually compare the charging curves of the two batteries.

LiFePO4 charging mode

The charging behavior of LiFePO4 must conform to a specific curve to ensure that the battery can be fully charged and remain healthy.

• CC (Constant Current) Phase (T1) Initially, a discharged battery is charged at a constant current and the voltage increases steadily until the constant voltage set point is reached, which varies depending on the charging method.
  
• CV (Constant Voltage) Phase (T2) During this phase, the battery maintains a constant voltage while the current gradually decreases to 2A (0.02C), also known as tail current. At this point, charging stops and the battery is fully charged.

Charge LiFePO4 correctly with LiFePO4 chargers

Charging LiFePO4 batteries with LiFePO4 battery chargers is considered one of the safest and most reliable methods. These chargers are specifically designed to charge LiFePO4 batteries with the correct voltage, current and charging algorithm, ensuring that the batteries are protected from overcharging and undercharging.

LiFePO4 battery chargers often have advanced features such as built-in temperature sensors that allow the charger to adjust the charging current according to the battery temperature to ensure optimal performance and extend the life of the battery.

In addition, LiFePO4 chargers are able to balance the battery pack's cells, which is necessary to prevent cells from discharging faster than others during charging, thus avoiding the risk of damaging the cells.

A single LiFePO4 battery cell has a nominal voltage of 3.2V and a recommended charging voltage range of 3.50V to 3.65V. It is important to note that exceeding a charging voltage of 3.65V can damage the battery cell due to its sensitivity to overvoltage and overcurrent.

Overvoltage can significantly affect the battery's performance, cause bloating, and even lead to damage and a shortened lifespan. Therefore, lithium batteries are usually equipped with a built-in BMS that provides protection against overvoltage. All LiTime LiFePO4 batteries have built-in battery management that protects the battery from overvoltage, overcurrent, overcharge, overdischarge, and high temperature.

The following table provides information on the voltage specifications of the various LiFePO4 batteries and systems.

Bonus Tip: Use LiTime LiFePO4 chargers

As for choosing a good LiFePO4 charger, that's another topic worth looking into. After evaluating various LiFePO4 chargers on the market, we have selected five LiFePO4 charger test winners, and we particularly recommend LiTime chargers.

In addition to the basic functions, LiTime chargers also offer many smart additional functions to improve the charging experience and user safety. For example, they have intelligent LED displays that show the current status such as standby, charging, fully charged and charging errors. They also offer comprehensive protection functions: protection against overtemperature, reverse polarity, short circuit, overcurrent and overvoltage. The integrated fan ensures that the battery does not overheat.

Conclusion

LiFePO4 batteries require special charging methods to ensure their optimal performance and longevity. While it is possible to charge a LiFePO4 battery with a regular charger, this is not recommended for long-term use as it can negatively affect the battery's lifespan and performance.

If you have purchased a LiFePO4 battery from a specific brand, it is best to purchase the charger that goes with it directly as this is the safest and best option.

FAQs

Can I charge LiFePO4 with a lead-acid charger?
It is not recommended because lead-acid chargers do not provide the correct charging parameters for LiFePO4 batteries. LiFePO4 batteries require more precise voltage and current control to be charged safely and efficiently.

What happens if you use the wrong charger for a lithium battery?
Using the wrong charger can lead to overcharging, overheating or even damage to the battery. In worst cases, this can significantly reduce the battery's lifespan or even cause safety risks.

Why do lithium batteries need a special charger?
Lithium batteries require a precise charging profile with precisely controlled voltage and current values ​​to maximize their lifespan and avoid safety risks. LiTime offers specially designed LiFePO4 chargers that perfectly meet these requirements, with intelligent features and multiple protection mechanisms.