UNI-T UT677A+ Battery Internal Resistance Tester with 3.5 inch TFT LCD, USB, 1000-Group Storage

For technicians who need rapid, repeatable battery diagnostics without bulky lab equipment, the UNI-T UT677A+ brings benchtop-grade internal resistance measurement into a handheld tool. Unlike generic battery testers that only read voltage, this meter applies a precise AC test signal to reveal cell degradation, loose connections, and early failure signs across lead-acid, Li-ion, NiMH, and NiCd chemistries. The 3.5-inch TFT colour display shows resistance, voltage, and temperature simultaneously, with pass/fail comparison for instant batch screening.

Highlights

• Wide internal resistance range: 0.000 mΩ to 3.100 Ω with auto or manual ranging
• High accuracy: ±(0.5% + 5 digits) for resistance, ±(0.1% + 5 digits) for voltage
• Voltage measurement up to 100.00 V DC, suitable for single cells and small battery packs
• Temperature measurement from -10 °C to 60 °C with ±1 °C accuracy
• Test current automatically adjusts from approximately 2 mA to 200 mA depending on range
• Stores 1000 measurement groups internally and exports via USB Type-C
• Built-in 3.7 V 3000 mAh Li-ion rechargeable battery for all-day field use
• Safety rated CAT II 100 V, CAT III 60 V

In daily use

The UT677A+ simplifies battery maintenance workflows. Connect the four-wire Kelvin clips to a cell, select auto range, and the meter immediately displays internal resistance, DC voltage, and ambient temperature. The comparison mode lets you set upper and lower limits, giving a clear PASS or FAIL indication for production testing or incoming inspection. Logged data can be transferred to a PC via the included USB interface and analysed with UNI-T's software, making it easy to track battery health trends over time. The rechargeable Li-ion battery eliminates the need for disposable cells, and the USB Type-C charging port works with common chargers.

Full specifications

• Display: 3.5-inch TFT LCD
• Internal resistance range: 0.000 mΩ ~ 3.100 Ω (auto/manual ranging)
• Internal resistance accuracy: ±(0.5% + 5 digits)
• Voltage range: 0.000 V ~ 100.00 V DC (auto/manual ranging)
• Voltage accuracy: ±(0.1% + 5 digits)
• Temperature range: -10 °C ~ 60 °C, accuracy ±1 °C
• Test current: approx. 2 mA to 200 mA (range-dependent)
• Data storage: 1000 groups
• Communication: USB (Type-C)
• Power supply: 3.7 V 3000 mAh Li-ion battery
• Safety rating: CAT II 100 V, CAT III 60 V
• Applicable battery types: lead-acid, Li-ion, NiMH, NiCd, and others
• Comparison function: yes (pass/fail judgment)
• PC software: yes (data analysis and export)
• Operating temperature: 0 °C ~ 40 °C
• Operating humidity: ≤75% RH

Final note

With its high accuracy, data logging, and comparison mode, the UNI-T UT677A+ is a practical choice for battery manufacturers, service centres, and quality control labs that need reliable internal resistance testing in a portable form factor.