Can I Use LiFePO4 Battery While Charging?

By Matthew Joseph Nandirio •  Updated: 11/13/22 •  4 min read

Charging a battery seems like a simple task. Besides, as the LiFePO4 battery is the safest and longest-lasting battery right now, you might think charging-related common problems won’t do any harm to it. 

But can you use the LiFePO4 battery while charging? Well, the answer I’m going to give in this write-up. So, let’s dive deeper.

can you use the LiFePO4 battery while charging

Yes, you can.! The best way is to only use small loads while charging your LiFePO4 battery. Otherwise, It will mess up the charge cycle and slow down the charging process. Hence, your battery will suffer in the long run. 

Is It Good for The LiFePO4 Battery Life to Use It While Charging?

Use It While Charging
Don’t use while Charging

In a word, No. Using your LiFePO4 battery while charging is not good for the battery life. Doing it over and over will reduce its lifespan and capacity.

It Overcharges Your Battery 

When you use one or multiple loads while charging your Lifep4 battery, they draw current from your charger. As a result, the charging cycle will become slower. 

Sometimes, some low-end charger tries to detect the state of charge- your battery will send an incorrect report. 

That’s why the charger ends up overcharging your battery. It creates an overheating problem for battery cells. As they become overheated, the battery lifespan will decrease over time. 

It Reduces Your Battery’s Lifecycle 

According to a study, “increasing the operating temperature increases the degradation rates of all components in Lithium batteries, including their maximum storage capacity and lifecycle.” 

As the temperature increases inside the battery cells because of overcharging, the chemical reaction speed inside the cells increases as well. This increasing reaction speed can further increase the output of your LiFePO4 battery. 

As a result, it eventually increases the degradation speed of the battery as a whole. That’s how the high temperature created by using a battery while charging can shorten the lifespan of your LiFePO4 battery. 

What Happens When You Use LiFePO4 Battery While Charging?

When you charge a battery, the voltage of the charge is higher than the voltage of the battery. That’s why current flow from the charger to the battery, not vice versa. 

Several things will happen if you attach a load while charging your LiFePO4 battery.

Slows Down the Charge Cycle 

 take more time to charge

Firstly, the load will draw power, not from the battery; rather charger or charging circuit will power up that load. So, your charger will take more time to charge your battery fully. 

Messes Up the Charging Cycle

Secondly, a LiFePO4 battery charger stops charging the battery when it reaches a pre-defined threshold. But if a load is drawing current from the charger or battery while taking charge, it won’t be possible to correctly detect the charge termination as current consumption is really high.

As a result, your battery will send a different voltage report to the charger with a load than its actual voltage rate without any load attachment. It will create a total mess in the charge cycle. 

Note: I have seen this problem with low-end solar chargers. However, high-quality solar chargers didn’t have such problems.

Heats Internal Components

Using a battery while charging will eventually lead your battery to overcharge and generate unnecessary extra heat, which might damage the battery in the long run. 

The short-term consequences might be minor depending on how the charger behaves, and the BMS takes control of the situation. But it will affect your LiFePO4 battery in the future. Your battery may have a reduced capacity and shortened lifespan. 

However, you can use small-energy loads while charging your LiFePO4 battery, based on your load and charger circuits. In theory, it’s possible to design a charger circuit that will allow the charger and battery to power up the load together. 

It’s a pretty complex structure, and you must ensure the specific cycle of charging to ensure maximum lifespan for your battery. But no matter what you do, connecting a load when taking charge will slow down the charging process. 

Final Thoughts

Charging a LiFePO4 battery needs proper attention. Since it’s an expensive battery, you should look after every little thing, including not using any load while charging your battery. It will help your battery last longer as scheduled. 

References 

1. P. Michael et al. (2015). Effect of Temperature on the Aging rate of Li-Ion Battery Operating above Room Temperature. 

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Matthew Joseph Nandirio

Matthew Joseph Nandirio is the Founder of walkingsolar. After graduating from the University of Houston in 2002, matt started working as an electrical and electronic engineer for several multi-national solar energy companies. He has a wide range of experiences including solar system requirement analysis, planning, maintaining, debugging and even solar device development through research. He now shares his 20 years of expertise through his articles on the walkingsolar website. Further, he is also the author of two books on Solar Technology, “Solar Power for Villages” and “DIY Solar System for Dummies”.

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