Detection and maintenance of the overcharge protection function of the charger

The detection and maintenance of the overcharge protection function of the charger is an important link to ensure charging safety and extend battery life. The following are the key points:

Detection method

Simulated overcharge test

Use an intelligent load device or battery simulator to gradually increase the charging voltage/current until it exceeds the rated value (for example, the overcharge protection voltage for lithium batteries is usually 4.2-4.35V), and observe whether the charger automatically stops charging after the protection is triggered.

Record the voltage/current value when the protection is triggered and compare it with the product specification to confirm whether it is within the safety threshold.

Protection recovery test

After triggering the overcharge protection, reduce the voltage/current to the recovery threshold (such as 3.6-3.8V), and check whether the charger can automatically resume the charging function to ensure that the protection logic is reversible and there is no locking fault.

Long-term stability test

Conduct continuous charge and discharge cycle tests on the charger (such as over 100 times) to verify the reliability of the overcharge protection function after long-term use and prevent protection failure due to component aging.

Thermal impact test

Conduct overcharge tests in high-temperature (such as 40℃) or low-temperature (such as 0℃) environments to observe whether the protection function fails due to temperature influence and ensure environmental adaptability.

Key points of maintenance

Regular functional verification

Every 6 to 12 months, use professional equipment to conduct overcharge protection tests on the charger, record the changes in the trigger threshold, and if the deviation exceeds ±5%, timely maintenance or replacement is required.

Component aging inspection

Focus on inspecting the key components in the overcharge protection circuit (such as voltage detection chips and MOSFET tubes). If the performance of the components declines (such as increased leakage current), they need to be replaced immediately.

Maintenance of heat dissipation system

Clean the dust from the charger's heat dissipation holes to ensure that the fan or heat sink is not clogged. If the charger temperature exceeds 85℃ during the overcharge test, the heat dissipation design needs to be optimized or the ambient temperature reduced.

Software calibration (for smart chargers)

If the charger is equipped with an MCU for control, the firmware needs to be updated regularly to fix the protection logic vulnerabilities, and the voltage/current detection errors should be corrected through calibration tools.

Battery compatibility test

Conduct overcharge protection tests on different types of batteries (such as lithium batteries and lead-acid batteries) to ensure that the charger can adjust the protection threshold according to the battery characteristics, avoiding false triggering or failure.

Precautions

Safe operation: Insulating gloves must be worn during testing to avoid high-voltage electric shock.

Data recording: Record in detail the voltage/current values, trigger time, and ambient temperature of each test, and establish a maintenance file.

Compliance: Ensure that the testing methods comply with international safety standards such as IEC 62368-1 to avoid product recalls due to non-standard testing.