3.7v 2200mah 18650 lithium battery

　　How to repair the 3.7v 2200mah 18650 lithium battery pack protection board when it is abnormal

　　Some people bought an electric bicycle and did not use it for a long time. When they rode it again after a few months, they found that the electric bicycle was out of power and could not be charged. Plug in the charging head and the signal indicator light is always green. This is because the lithium battery voltage is too low and is too different from the charging head output voltage.

　　In this situation, it is generally said that the rechargeable battery is "starved to death". This type of rechargeable battery is usually replaced by a new rechargeable battery when sent to an after-sales service center. There are several ways to save this battery usage.

　　1. Series method.

　　A 12-volt rechargeable battery with all normal operating voltages is connected to all rechargeable batteries. For example, the original is a 48v20ah rechargeable battery, which is then connected to a 12v20ah rechargeable battery. A high-power 12V battery can continuously increase the working voltage of the entire battery, and then use the initial charging plug to recharge the battery, insert the charging plug, the charging plug light, and then charge the battery. The rechargeable battery is removed from the rechargeable battery when the charging plug is converted into a signal indicator light. All general rechargeable batteries.

　　2. Parallel connection method.

　　For example, the original 48v20ah rechargeable battery, in addition to a series of 48v20ah rechargeable batteries, the high working voltage end will be introduced to the low working voltage end. This method is also used by many rechargeable car lithium-ion battery agents to check that there is no rechargeable battery, and can also be used as a destination for battery charging.

　　3. Low voltage charging method.

　　Battery charging is carried out using a small or medium-sized charging plug. For example, a 60v20ah rechargeable battery can be charged using a 48v20ah charging plug. It is generally covered.

　　The above methods all require professional personnel to operate the entire process, because of the high specificity of lithium batteries, so as to avoid non-standard operation and resulting risks due to small losses.

　　3.7v 2200mah 18650 lithium battery is a voltage close to 12v obtained by connecting several lithium batteries in series. When we connect lithium batteries in series, we must use the 3.7v 2200mah 18650 lithium battery protection board, which can protect the series connected lithium battery pack. When the lithium battery is full of power, it can have the function of equalizing the voltage differences of each individual lithium battery, effectively solving the system vulnerability of the series circuit. So how to repair the 3.7v 2200mah 18650 lithium battery pack protection board when there is an abnormality?

　　List some common problems with lithium battery protection boards for analysis and maintenance.

　　1. There is no working voltage or the voltage is abnormal.

　　If there is no voltage or there is an abnormality in the voltage, we should adjust the multimeter to the DC 20V setting, and then touch the positive voltage of the lithium battery cell with the red meter pen and touch the lithium battery cell with the black meter pen. Negative level, if the digital multimeter shows no voltage or the voltage is very low, it means the lithium battery is damaged. Pay attention to check whether the positive and negative connections of the lithium battery protection board are reversed. If the connection is wrong, the charger will be forced to lose power when charging the lithium battery pack.

　　2. No over-current protection

　　If there is no over-current protection, etc., first check whether the power circuit of the over-current detection pin is defective. If so, replace the protection IC.

　　3. No resistance or excessive resistance

　　The cause must be found from the identification power circuit of the resistance welding machine board. Check whether the resistor has poor contact, whether it is the wrong resistor, whether there is a short circuit fault or a lead, etc.

　　4. Cannot be charged

　　Use the multimeter power switch to select the 20V gear, and then use the red meter pen to touch the positive stage of the lithium battery cell or the battery protective plate. If the multimeter shows voltage, we need to analyze it according to the following conditions : Is there an output voltage? Is the voltage of the lithium battery normal? If the above voltages are abnormal, we can basically determine that the protection IC or MOS tube has been damaged. At this time, we only need to replace these two components.

　　5. There is no internal resistance or the internal resistance is too large

　　1. If there is no internal resistance, you need to check whether the pins of the mos tube are damaged. If so, just replace the mos tube.

　　2. If the internal resistance is too large, you need to use a probe to touch the electric fish lithium battery protection board to check whether there is poor contact or excessive oxidation. It is also necessary to check whether there are too many nickel flakes on the lithium battery core. If there are too many nickel flakes on the lithium battery core, it will also cause excessive internal resistance.

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