YR1035+ Battery Internal Resistance Tester – True 4-Wire, 18650/21700/LiFePO4

YR1035+ Battery Internal Resistance Tester – True 4-Wire

The tester we use on our own bench to grade and match cells before every rebuild. Internal resistance (IR) tells you far more about a cell's health than voltage alone: high-IR cells heat up, sag under load, and drag down the whole pack. Measure IR and voltage at the same time, then group cells with matching readings for a balanced, long-lasting pack.

Why rebuilders use it

• True 4-wire (Kelvin) measurement – lead resistance doesn't skew the reading
• IR and voltage on one screen – grade cells in seconds
• Works with 18650, 21700, LiFePO4, and large prismatic cells
• USB rechargeable

Specifications

• Internal resistance range: 0.00001Ω – 200Ω
• Voltage range: 0.00001V – 100V
• Operating temperature: 10°C – 40°C
• Includes Kelvin clip leads and probe leads
• Packaged weight: approx. 1.0kg

Tip: For cell matching, measure all cells at the same temperature and state of charge, then group cells within a few milliohms of each other.