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Outdoor wall light manufacturers|how to install How long does it take to charge an 18650 battery?|Sunshinelux

July 30, 2022

If it is 350MA output, the charging time of your battery is: battery capacity*1.5/350, for example, if the capacity of your 18650 lithium battery is 2400MAH, it is 2400*1.5/3500=10.28 (hours), but now lithium The indicator light on the battery charger does not work properly due to some special reasons. You may use your voltmeter to test the voltage of your battery. If the voltage is within the range of 4.2V-4.3V, it means that the battery is fully charged. More than 95% of lithium battery chargers are protected, and generally 18650 lithium batteries are mostly 2000MAH-2600MAH, so your charger can basically be fully charged after the charging time exceeds 10 hours, and there is no need to consider overcharging. Problem. It is common for battery chargers to heat up. Now, if the temperature of your battery itself is relatively low, it means that the charger is no longer charging the battery. The battery is hot during the initial period of charging (0-6 hours). It's just that the link you gave doesn't work, so I don't know what kind of charger you're using.


The charging process of lithium-ion batteries can be divided into four stages: trickle charging (low voltage precharge), constant current charging, constant voltage charging, and charging termination.


The basic requirements of lithium battery chargers are specific charging current and charging voltage, so as to ensure the safe charging of the battery. Additional charge assist functions have been added to improve battery life and simplify charger operation, including trickle charge for overdischarged batteries, battery voltage detection, input current limit, charger shutdown when charging is complete, automatic battery charging after partial discharge Start charging, etc.


Calculation of charging time and discharging time of 18650 lithium battery


Low temperature lithium iron phosphate battery 3.2V 20A

Low temperature lithium iron phosphate battery 3.2V 20A

-20℃ charge, -40℃ 3C discharge capacity≥70%

Charging temperature: -20~45℃

-Discharge temperature: -40~+55℃

-40℃ support maximum discharge rate: 3C

-40℃ 3C discharge capacity retention rate≥70%


Calculation of charging time and discharging time of 18650 lithium battery


Phase 1: Trickle Charge - Trickle charge is used to pre-charge (recovery) fully discharged cells first. When the battery voltage is lower than about 3V, trickle charging is used. The trickle charging current is one-tenth of the constant current charging current, which is 0.1c (for example, the constant charging current is 1A, the trickle charging current is 100mA).


Stage 2: Constant current charging - when the battery voltage rises above the trickle charging threshold, increase the charging current for constant current charging. The current for constant current charging is between 0.2C and 1.0C. The battery voltage gradually increases with the constant current charging process. Generally, the voltage set by a single battery is 3.0-4.2V.


Phase 3: Constant voltage charging - when the battery voltage rises to 4.2V, the constant current charging ends and the constant voltage charging phase begins. According to the saturation degree of the cell, the charging current gradually decreases from the maximum value as the charging process continues. When it decreases to 0.01C, the charging is considered to be terminated. (C is a way of expressing the nominal capacity of the battery against the current. For example, if the battery has a capacity of 1000mAh, 1C is the charging current of 1000mA.)


Stage 4: Charge Termination - There are two typical methods of charge termination: using minimum charge current judgment or using a timer (or a combination of the two). The minimum current method monitors the charge current during the constant voltage charging phase and terminates the charge when the charge current decreases to the 0.02C to 0.07C range. The second method counts from the start of the constant voltage charging phase and terminates the charging process after two hours of continuous charging.


Low temperature high energy density 18650 3350mAh

Low temperature high energy density 18650 3350mAh

-40℃ 0.5C discharge capacity≥60%

Charging temperature: 0~45℃

Discharge temperature: -40~+55℃

Specific energy: 240Wh/kg

-40℃ discharge capacity retention rate: 0.5C discharge capacity≥60%


Generally, the capacity of the battery is indicated on the battery, in milliamps, the larger the value, the greater the capacity.


For example: 1200mAh means that the capacity of the battery is 1200mAh. At the same time, the charger is generally marked with the charging current, also in milliamps.


In this way, the battery charging time can be simply calculated as follows: the battery capacity is divided by the charging current, multiplied by a factor of 1.2 (or 1.1), and the time unit is hours. For example: the battery capacity is 1200 mA, the charging current of the charger is 600 mA, and the charging time is (1200 mA/600 mA) & TImes; 1.2=2.4 hours, then the charging time of this battery using this charger is for 2.4 hours.


The above calculation method does not apply to new batteries. Generally speaking, when charging new batteries for the first three times, especially for nickel-cadmium batteries and nickel-metal hydride batteries, the standard charging time is about 15 hours (0.1C), so that the battery life can be maximized. In the future, you can refer to the above method to calculate the battery charging time.


What is the charging current marked on the charger?


I can give you a simple formula: charge and discharge time (minutes) = capacity * 1.1 / current (mA) * 60

The relationship between the battery charging time and the charging current is that the battery capacity is divided by the charging current to obtain the charging time. Considering the loss during the charging process, the calculated charging time is multiplied by the constant 1.1 or 1.2.


According to the logo, you can calculate an approximate time. If it is an ordinary charger and the current is very small, the charging time must be very long.

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