2-Channel 18650 21700 Battery Capacity Tester with Internal Resistance Meter, 1A Charge/Discharge

2-Channel 18650 / 21700 Battery Capacity Tester with Internal Resistance Meter This compact 2-channel battery tester is designed for testing 18650 and 21700 lithium-ion cells. It supports capacity testing, internal resistance measurement, charging, discharging, and automatic cycle testing, making it a useful tool for DIY battery builders, hobbyists, and anyone sorting or checking individual cells. The tester includes built-in 18650 holders as part of the main unit. For testing 21700 cells, an external 21700 holder is required. That external holder is a separate option and is not included unless specifically selected. Each channel works independently, allowing you to test two cells at the same time with separate settings and operation. The unit also includes fan cooling for improved heat dissipation during discharge testing. Key Features 2 independent test channels Built-in holders for 18650 cells Supports 21700 cells with optional external holder Measures battery capacity and approximate internal resistance Supports charging and discharging functions Automatic mode supports up to 9 charge/discharge cycles Adjustable discharge cutoff voltage from 2.5V to 3.5V Type-C power input Active fan cooling English and Chinese system language Specifications Working Voltage: DC 5V Power Supply Interface: Type-C Supported Batteries: Lithium-ion batteries with stop discharge voltage from 2.5V to 3.5V, start voltage from 2.8V, and full charge voltage up to 4.2V Supported Cell Sizes: 18650, 21700 Built-In Battery Holders: 18650 only 21700 Compatibility: Requires optional external 21700 holder, not included unless selected Test Channels: 2 Internal Resistance Measurement: Yes, DC two-wire method Charging Function: Supported Charging Current: Up to approximately 1A Charge Full Voltage: 4.2V Charge Termination: Below 0.1A current Discharge Function: Supported Discharge Current: Up to approximately 1A, non-constant, non-adjustable Automatic Charge/Discharge: Supported Cycle Count: Adjustable from 1 to 9 cycles in automatic mode Status Alert: Supported Cooling: Fan active heat dissipation Overheating Protection: Supported Adjustable Stop Discharge Voltage: 2.5V to 3.5V in 0.1V steps Power Failure Save: Saves setup parameters only, does not save measurement data Product Size: 190 × 50 × 27 mm Important Notes Not suitable for LiFePO4 charging Internal resistance measurement uses a DC two-wire method, so values are for reference only Discharge current is not adjustable If no battery is installed, the internal resistance may display 9999 mΩ Capacity results should be judged from the discharge portion of the test Discharge components may become hot during testing 21700 testing requires the optional external holder if your package does not include it Package Includes 2-Channel Battery Capacity and Internal Resistance Tester ×1 Important: This unit includes built-in 18650 holders. The external 21700 holder is a separate option and is not included unless specifically selected with that package version.