1. Phenomenon description

When performing constant voltage (CV) charge, constant voltage (CV) discharge, or constant current-constant voltage (CC-CV) charge/discharge tests using NEWARE battery test systems, the current quickly rises to the upper limit of the 1 mA range. After that, the system cannot maintain constant voltage output and automatically switches to constant current (CC) mode, causing the CV step to fail.

2. Root cause

The auto-ranging function is enabled. When the current is small, the system automatically switches to the 1 mA low range, limiting the maximum output current to 1 mA.

3. Principle explanation

In constant voltage mode, the current range only supports automatic switching from high to low ranges, and does NOT support reverse switching from low to high ranges.Once the system switches to the 1 mA low range, the maximum current is locked and cannot meet the output demand of CV mode. The CV function then fails, and the system automatically enters a constant current limited state.

By fixing the current range to an appropriate gear (e.g., 10 mA), the low-range current limit is lifted, ensuring stable operation in CV mode.

4. Operating steps

• Enter the charge/discharge step editing interface.

• Double-click the blank area under the “Others” option.

• Under Protection Conditions / Recording Conditions, select the parameter: Current Range.

• Set it to Fixed Range (select a gear larger than the test current, e.g., 10 mA).

• Save the parameters and restart the CV charge/discharge step.

After fixing the range, the maximum current is the upper limit of the selected range and will not be restricted by the low range. Constant voltage mode can be maintained normally, making the test more stable and accurate.

5. Applicable tests

• Constant Voltage Charge (CV)

• Constant Voltage Discharge (CV)

• Constant Current-Constant Voltage (CC-CV) Tests