Regular inspection methods for the electronic components inside the charger

The regular inspection of the internal electronic components of electric vehicle chargers should follow a systematic process, combined with professional tools and safety regulations. The following are the specific inspection methods and key points:

First, inspection cycle and scope of application

Cycle recommendation: Conduct a comprehensive inspection every six months or after driving 10,000 kilometers. If the vehicle is in a high-temperature, humid or dusty environment, it should be shortened to once every three months.

Scope of application: It covers the core components inside the charger, including fuses, power modules, filter capacitors, power switch tubes, control chips, etc.

Second, inspection methods and steps

Visual inspection

Fuse status: Use a multimeter to measure whether the fuse is open or directly observe its appearance to see if it is blown.

Component integrity: Check the circuit board for any signs of charring, bulging, cracking or liquid leakage, with a focus on high-voltage filter capacitors, power devices, etc.

Connection reliability: Confirm that there is no false soldering or desoldering at the solder joints, especially for the pin connections of large-mass components such as high-frequency transformers and inductors.

Electrical performance test

Power input detection

Use the AC range of a multimeter to measure whether the incoming voltage of the power supply is 220V.

Use the resistance setting or diode setting to detect whether the input line is open-circuited.

Measurement of key components

Diode: Use the diode setting to measure the forward voltage drop. The normal value is approximately 0.6V. Reverse response cut-off.

Resistance: Measure whether the resistance value is consistent with the nominal value. If the deviation exceeds ±5%, replacement is required.

Capacitance: Measure the capacity with the capacitance range. An error within ±10% is considered qualified. For electrolytic capacitors, it is necessary to pay attention to the polarity and discharge them before testing.

Power device inspection: Check the voltage drop of power switch tubes such as MOSFET and IGBT to confirm that their conduction and cut-off states are normal.

Functional verification

Indicator lights and display screen: After power-on, check whether the indicator lights are lit up normally and whether the display screen shows the charging parameters (such as voltage and current).

Charging test: Connect the battery to conduct an actual charging test, observe whether the charger can start normally, adjust the output voltage, and automatically stop when fully charged.

Insulation and safety testing

Insulation resistance: Measure the insulation resistance between the input and output terminals of the charger and the housing with a megohmmeter. It should be greater than 2.5MΩ.

Withstand voltage test: Apply a test voltage higher than the working voltage (such as 500V) to the charger for 1 minute to confirm no breakdown or flashover.

Third, professional tools and safety requirements

Tool list: Multimeter, megohmmeter, capacitive meter, soldering iron, hot air gun, oscilloscope (optional).

Safety regulations:

Make sure the charger is powered off and discharged for at least 10 minutes before operation.

Wear insulating gloves and goggles to avoid electric shock or injury from splashing components.

Use anti-static wristbands to prevent static electricity from penetrating sensitive components.

Fourth, Common Faults and Their handling

No output voltage

Possible causes: blown fuse, damaged power module, faulty control chip.

Solution: Replace the fuse, test the input and output voltages of the power module, and replace the chip if necessary.

Abnormal output voltage

Possible causes: feedback loop failure, optocoupler damage, output filter capacitor failure.

Solution: Check the feedback resistor and optocoupler, and replace the failed capacitor.

The charger is overheating.

Possible causes: clogged heat sink, fan failure, aging of power devices.

Solution: Clean the heat sink, replace the fan or power device.

Fifth, maintenance suggestions

Regular cleaning: Use compressed air to clean the dust on the heat sink and circuit board every quarter to prevent dust accumulation from causing poor heat dissipation.

Component replacement: Preventive replacement is carried out on components that have aged or declined in performance, such as electrolytic capacitors.

Software upgrade: If the charger supports firmware updates, regular upgrades should be carried out to fix potential vulnerabilities.