18650 Battery Capacity & Internal Resistance Tester | Type-C

18650 Lithium Battery Capacity & Internal Resistance Tester – Dual Channel, Type-C

Take the guesswork out of battery testing with this professional-grade 18650 Lithium Battery Capacity Tester. Featuring dual independent channels, automatic charge/discharge cycling, and a built-in digital display, this module delivers precise mAh, mWh, and internal resistance readings — all powered via a convenient Type-C interface.

Whether you're sorting batteries for reuse, testing capacity before a project, or grading cells for DIY power banks, this compact and intelligent tester gives you the data you need fast.

Key Features

• Dual Independent Channels: Test two 18650 batteries simultaneously — each channel operates independently with no cross-interference.
• Automatic Charge & Discharge Cycling: Supports up to 9 charge/discharge cycles in automatic mode for accurate capacity grading.
• Internal Resistance Measurement: Uses the DC two-wire method to measure internal resistance in milliohms — ideal for identifying degraded or mismatched cells.
• mAh & mWh Readout: Displays both capacity (mAh) and energy (mWh) for comprehensive battery analysis.
• Type-C Power Input: Modern USB Type-C interface for reliable, reversible power connection (cable included).
• Active Fan Cooling: Built-in fan dissipates heat during discharge testing to maintain safe operating temperatures.
• Overheating Protection: Automatic shut-off protection safeguards both the device and your batteries.
• Adjustable Stop-Discharge Voltage: 11-step adjustable from 2.5V to 3.5V for customized discharge cut-off.
• Bilingual Interface: Supports both Chinese and English display languages.
• Compact Battery Holder: Sturdy clip-style holder compatible with flat-top 18650 cells.

Technical Specifications

• Working Voltage: DC 5V (via Type-C)
• Applicable Batteries: 18650 Li-ion cells (stop discharge 2.5–3.5V; start 2.8V; full 4.2V)
• Charging Current: Max ~1A; auto cut-off when current drops below 0.1A
• Discharge Current: Max ~1A (non-adjustable)
• Charge Voltage: 4.2V (not suitable for lithium iron phosphate / LiFePO4 batteries)
• Resistance Measurement: DC two-wire method
• Cycling: 1–9 cycles (automatic mode only)
• Heat Dissipation: Active fan cooling
• Product Dimensions: 188 × 50 × 36 mm
• Language: Chinese / English
• Country of Origin: Made in China

How to Use

1. Power On: Connect USB Type-C power — the unit powers on automatically. Disconnect to shut off.
2. Language Switch: Hold "Menu/M" while powering on to toggle between Chinese and English.
3. Switch Channel View: Press the "Channel/CHN" button to navigate between Channel 1 and Channel 2 settings and readings.
4. Internal Resistance Test: Install battery and wait ~10 seconds after power-on to read voltage and internal resistance. A reading of "9999 mΩ" indicates no battery is installed or the cell cannot be identified.
5. Capacity Test: Set mode to "Discharge" or "Auto," press Start/Stop (R/S) to begin. Caution: discharge resistor becomes hot — do not touch during testing.
6. Cycle Grading: In Auto mode, set 1–9 cycles. Stop-discharge voltage must be ≥ 2.8V for cycling to work correctly.
7. Data Reset: Capacity, energy, and time data auto-clear on shutdown or mode change.

What's in the Box

• 1× 18650 Battery Capacity & Internal Resistance Tester (Type-C)
• 1× Type-C Power Cable

Note: Battery not included. Not suitable for charging lithium iron phosphate (LiFePO4) batteries.

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Frequently Asked Questions

Q: What type of batteries can I test with this 18650 battery capacity tester?

A: This tester is designed specifically for standard 18650 lithium-ion (Li-ion) cells with a nominal voltage range of 2.8V–4.2V. It is NOT suitable for testing or charging lithium iron phosphate (LiFePO4) batteries. Both flat-top and standard 18650 cells are supported via the compact battery clip holder.

Q: Can I test two batteries at the same time?

A: Yes! This tester features two fully independent channels. You can insert two 18650 batteries simultaneously, and each channel will operate on its own schedule with no interference. You can set different modes, stop voltages, and cycle counts for each channel independently.

Q: How accurate is the internal resistance measurement?

A: The tester uses the DC two-wire method for internal resistance measurement. While this provides a useful relative reading for sorting and comparing cells, it is subject to the inherent limitations of the two-wire technique. If a cell cannot be identified or has extremely high resistance, the display will show "9999 mΩ". For the most accurate capacity assessment, use the discharge capacity reading as your primary reference.

Q: Does this tester require a separate power supply?

A: The tester is powered via a standard USB Type-C connection at DC 5V — a USB Type-C power cable is included. A 5V USB adapter or power bank (not included) is required to supply power. The unit has no on/off switch; it powers on when connected and shuts off when disconnected.