Fnirsi FNB-C2 USB-Lade- und Ladeprotokoll-Tester

FNIRSI FNB-C2 is a USB-C tester and fast-charging protocol trigger, suitable for diagnosing chargers, cables, and power banks. It is connected between the source and the load and displays voltage, current, power, and the negotiated charging protocol in real time. Thanks to support for PD3.1 EPR, it covers the range of 4-50V and 0-6.5A, i.e. up to 240W. It can therefore handle even high-power laptop chargers. It is ideal for a quick check of which protocol was actually agreed between the charger and the device and how much power is really flowing, for example when charging FPV goggles, a transmitter, or a power bank.

Measurement is handled by an external 20-bit ADC with a 7-digit display — resolution is 0.000001V/A/W, accuracy is ±0.02% of reading for voltage and ±0.05% for current and power. In addition to the main VBUS bus, it also measures voltage on the D+/D- data lines and CC1/CC2 pins and monitors its own operating temperature with 1°C resolution, which is useful during long-term high-power operation.

Automatic detection recognizes PD2.0/PD3.0/PD3.1 protocols (including PPS and EPR), QC2.0/3.0/4/5, UFCS, Samsung AFC, Huawei FCP/SCP, OPPO VOOC/SVOOC1.0/2.0 and VIVO VFCP; individual protocols can also be triggered manually. The PD monitor function captures PD communication packets between the charger and the device, helping to reveal why fast charging is not being negotiated. The QC to PD converter also allows QC devices to be charged from a PD charger.

The tester reads the E-Marker chip in the USB-C cable — type, power, length, data rate, and version for 3A/5A/50V/EPR cables as well as Thunderbolt TBT3/TBT4. This makes it easy to verify whether the cable really handles the declared power. It can also simulate cables (without E-Marker 60W, 20V/5A 100W, or 50V/5A 240W EPR), allowing the charger to be tested with different cable types without physically swapping them.

The quality of the power source is assessed by dual-mode waveform measurement: slow plotting of voltage, current, and D+/D- curves with 2Sa/s-1kSa/s sampling, and fast ripple measurement with AC coupling and 20kSa/s-2MSa/s sampling. The VBUS voltage waveform can be monitored in real time at a frequency adjustable from 20kHz to 2MHz.

10 groups of statistics are available for capacity (Ah), energy (Wh), and time; from the measured data, the tester calculates battery capacity with adjustable cell voltage of 3.0-5.0V and conversion efficiency of 80-100%. Voltage and current curve recording runs for up to 9 hours with a saving interval of 1-120s and optional auto-start and auto-stop conditions — the entire charging cycle is documented without assistance.

Everything is displayed on a 1.54" 240x240 TFT display. The sensor automatically rotates the image in four directions. The tester has three connectors: USB-C male and USB-C female (24-pin, bidirectional current flow) and a HID USB-C port for connection to a computer — on Windows and Mac OS it works without driver installation. During firmware updates, the device appears as a flash drive; just drag the firmware file onto it.

Important notice: Do not apply more than 50V to the measurement input and no more than 16V to the PC port. When manually triggering higher voltage, no device that cannot tolerate that voltage must be connected to the tester.