What is a lithium-ion battery？

Lithium-ion batteries (Li-ion) appear in our daily lives, from powering electronic vehicles, lawnmowers, chainsaws, and phones to smart thermometers. When compared to other rechargeable batteries, lithium-ion batteries have a high energy density, which provides more power in a smaller, lighter package.  When it comes to charging, Li-ion can be charged quickly and has a low self-discharge rate, meaning it retains its power when not being used.  

Find out how to charge lithium batteries safely and efficiently. The most popular methods for charging lithium batteries are below. 

How to charge lithium battery：Scientific, safe and efficient charging methods？

1. Choose the Right Charger

● Lithium batteries must use a dedicated charger. Using a regular NiMH/NiCd battery charger may damage the battery due to mismatched voltage or current.

● Constant Current and Constant Voltage (CC/CV) Charging: High-quality lithium battery chargers use a constant current (CC) followed by constant voltage (CV) charging method to ensure efficient and safe charging.

● Smart Recognition: Some chargers automatically detect the battery type (e.g., 18650, 21700, LiPo) to prevent overcharging.

● Fast Charging Support: If the battery supports fast charging (e.g., USB PD/QC protocols), a matching fast charger can be used, but long-term fast charging may affect battery life.

2. Follow Correct Charging Steps

Incorrect connection order may cause surges or poor contact. It is recommended to follow these steps:

● Connect the charger to the power source (outlet/USB interface) first.

● Then insert the battery (to avoid voltage shock during insertion or removal).

● After charging is complete, first disconnect the battery, then power off the charger.

● If the battery has not been used for an extended period (e.g., more than 3 months), it is recommended to perform a shallow charge and discharge (30%-50%) before storage to avoid deep discharge damage.

● Avoid metal objects touching the terminals during charging to prevent short circuits.

3. Avoid Extreme Charging States

● Lithium batteries are most susceptible to two conditions: excessive discharge (0%) and excessive charging (100%).

● Do not wait for the battery to drain completely before charging (below 20% can accelerate aging).

● It is not necessary to charge to 100% every time. Storing the battery at full charge for long periods can cause lithium ion deposition, reducing capacity.

● Optimal Charging Range: 20%-80% (keeping the battery within this range during daily use can extend its lifespan).

● If stored at 100% charge for long periods → capacity may decrease by 20% after 1 year.

● If kept between 40%-60% charge for long periods → capacity degradation is the slowest.

4. Control Charging Environment Temperature

● High and low temperatures can damage lithium batteries.

● Long-Term Storage Charging Management

● If the lithium battery is not in use for a long time (e.g., backup batteries, seasonal devices):

● Charge to 40%-60% (fully charged or fully discharged will accelerate aging).

● Check the battery every 3 months, and if the charge drops below 20%, recharge to 50%.

● Store in a cool, dry place (ideal temperature 15°C~25°C).

How do you wake up a dead lithium battery?

A sleeping lithium battery may be roused in many ways. You can do anything from charging the battery with solar energy to warming it up and connecting many lithium batteries in parallel to power your sleeping battery. These methods will wake a sleeping lithium battery more safely and straightforwardly.

● Check Voltage: Measure the voltage of your battery with a multimeter or a battery voltage tester. If the voltage drops below a certain point—often between 2.5 and 2.8 volts per cell—the battery may be in a deep drain condition.

● Verify Correct Charging Voltage: The charger has to be compatible with your lithium battery's voltage to charge it correctly. Each battery must have a voltage over 3.25 volts while using the charger. Release the battery from its "sleep" state with a charge of 3.65 volts per cell and a current of no more than C/10.

● Check The Signs of Recovery: Once in a while, check the battery voltage to see if it has risen to a satisfactory level, typically about 3.2 to 3.3 volts per cell. This will indicate whether the battery is showing signs of recovery. A rise in voltage indicates that the battery is reawakening and is ready to take a standard charge.

● Use Normal Charging: You can use a standard lithium battery charger or the same low-current charger until the battery voltage is sufficient, or you may use regular charging.

How long to charge lithium battery: Interpretation of Charging Time Factors

1. Interpretation of Charging Time Factors

● Battery capacity: The larger the capacity, the longer the charging time. For example:

● 2000mAh battery: Approximately 2 hours (using a 1A charger)

● 5000mAh battery: Approximately 5 hours (using a 1A charger)

2. Output current of the charger

● Standard charging: 0.5C (For a 2000mAh battery, use a 1A charger)

● Fast charging: 1C or higher (battery support required)

3. Charging stage:

● Phase One (Constant Current) : Quickly charge to approximately 70%-80% of the battery

● Phase Two (Constant Voltage) : Slowly charge to 100% to protect battery health

About our lithium battery charger

There are various types of lithium battery chargers, which can be integrated into your system or portable, depending on your needs. At Evlithiumcharger, you can find different charging devices for your power supply based on different application scenarios!

FAQ

What voltage should I use to charge my lithium battery?

The input capacity of each gadget and your location might affect the voltage required to recharge lithium batteries. On the label, in the user manual, or on the manufacturer's website, you should see the minimum and maximum voltage needed to charge your Li-ion battery entirely without damaging it.

Could I charge a lithium battery with a regular battery charger?

No, to put it simply. The voltage range at which lithium batteries function is greater than that of traditional batteries. Voltages of 12.8V for flooded lead acid, 13.0V for AGM, and 14.4V for LiFePo4 are all measured at 100% charge. When charging a battery, make sure the parameters match the voltage range of the battery. Understand the voltages used by lithium batteries better.

Ensure your gadget can charge or work at a specified voltage before plugging it in if you need more clarification. You risk breaking or ruining your gadget if you don't.