Calculation of charging and discharging time of 18650 lithium battery

Lithium ion batteries charging process can be divided into four stages: a trickle charge (low voltage prefilled), constant current, constant voltage charging and charging termination.

The lithium battery charger is the basic requirement of specific charging current and charging voltage, so as to guarantee battery security charge. Charging other auxiliary functions is added to improve the battery life, simplify the operation of the charger, including to discharge the battery trickle charging, battery charging voltage detection, input current limit, shut off after the completion of the charger and battery charge start automatically after a partial discharge, etc.

Phase 1: a trickle charge -- a trickle charge used to completely discharge the battery unit first prefi lled charging (recovery).At about 3 v battery voltage is lower than using a trickle charging, a trickle charging current is one over ten of the constant current charging current is 0.1 c (at a constant charging current is 1 a, for example, is a trickle charging current of 100 ma),

Phase 2: constant current charging, when the battery voltage rises to a trickle charge above the threshold value, improve the battery by constant current charging current.Constant current charging current between 0.2 C and 1.0 C.Battery voltage with constant current charge process gradually increases, the voltage of the common single battery set is 3.0 to 4.2 V.

Phase 3: constant voltage charging, when the battery voltage up to 4.2 V, the end of the constant current charging, began to constant voltage charging stage.Current depending on the degree of saturation batteries, as the charging process continued charging current by the maximum reduce slowly, when reduced to 0.01 C, think charging termination.(C is a sign of nominal capacity battery control current methods, such as the battery capacity is 1000 mah, charging current of 1000 ma is 1 C.)

Stage 4: charging end - there are two kinds of typical charging termination methods: USES the minimum charging current judgment (or a combination of both) or use a timer.The minimum current method to monitor stage, the charging current constant voltage charging, and reduce the charging current to the termination of charging 0.02 C to 0.07 C range.The second method from constant voltage charging stage at the beginning of time, continue to charge two hours after the termination of charging process.

General battery capacity size are marked on the battery, in ma, the bigger the numerical capacity.

18650 lithium batteriesCharging time and discharge time calculation

For example: 1200 mah is said of battery capacity is 1200 ma.At the same time, the charger is usually marked with charging current, also is an unit with ma.

In this way, the length of the battery charging time is according to the following method to calculate simply, battery capacity divided by the charging current, then multiplied by the coefficient of 1.2 (or 1.1), unit of time for hours.For example: the battery capacity is 1200 ma, the charger charging current is 600 ma, charging time is (1200 ma / 600 ma) & TImes;1.2 = 2.4 hours, then use this charger the battery charging time is 2.4 hours.

The above calculation method is not applicable to new battery.Generally speaking, a new battery for the first three time charge, especially the nickel cadmium battery and nickel metal hydride batteries, charging standards in 15 hours (0.1 C), so as to make the use time of battery reaches maximum value.Later can be reference to the above method to calculate the battery charging time.

What is marked on the charger of the charging current?

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

Battery charging time and the relationship between the charging current for the battery capacity divided by the charging current charging time, considering the loss in the process of charging, so will calculate the charge time multiplied by 1.1 or 1.2 this constant.

According to the logo, you can calculate a rough time.If it is a normal charger, and little current, charging time is very long.

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