FNIRSI FNB58 USB Tester – 4-28V, 7A, LCD, App, PD2.0/PD3.0 & QC2.0/QC3.0

Overview

Meet the FNIRSI FNB58 USB Tester — a compact, multi port power meter designed for makers, technicians, and testers who want to understand USB power behavior in real life. With a 2.0 inch TFT LCD and integrated USB A, Micro USB, and Type C interfaces, it offers a hands on way to observe how devices negotiate power in front of you. An external 16 bit ADC helps you capture precise readings, while built in protocol awareness makes it possible to follow fast charging negotiations without guessing.

The FNB58 is built to handle voltages from 4 to 28 volts and currents up to 7 amperes. This means you can test a range of chargers, cables, and devices with confidence, while the accompanying app provides a convenient way to log data and analyze results beyond what the screen alone can show. Acknowledging real world use, the tester emphasizes practical measurements and flexible testing setups that fit in a busy workshop or hobby bench.

Key benefits and real life uses

• Multi port testing lets you monitor USB A, Micro USB, and Type C connectors in a single session for quick cross comparisons.
• Clear readouts show voltage, current, power, resistance, and capacity, supporting fast checks during equipment setup or field tests.
• Fast charge protocol detection covers several standards including PD 2.0/3.0, QC 2.0/3.0, AFC, VOOC and more; monitoring happens automatically where supported.
• Six digit readout for voltage, current, and power plus 10 switchable capacity presets help you organize longer test runs.
• High resolution sampling and ripple analysis reveal transient power behavior, offering deeper insight into charging stability.
• Wire resistance measurement and E Marker / DASH cable data reading round out a thorough test profile.

Specifically useful scenarios

• Verify PD negotiation by observing protocol changes as you connect different cables and devices.
• Compare USB cables by tracking resistance and startup timing across multiple trials.
• Assess charging consistency for phones, tablets, power banks, and other USB powered gear using capacity and ripple data.

Getting the most from your tester

To support environmental goals, the package relies on a digital manual accessible via the QR code on the box. There you can find firmware updates and app details. Ensure the PD function switch is on and the correct input port is selected for accurate readings. If a protocol is not supported, the device may default to 5 V output, which can influence power measurements.

FNIRSI offers a practical, non medical tool that helps you explore power behavior with clarity and confidence while leaving room for interpretation of results.