Review of the USB Uni-T UT658

Uni-T UT658 USB Tester

The Uni-T UT658 USB Tester is a compact, USB flash drive-style meter that allows you to quickly check the voltage, current, and charging capacity of devices with a USB port. It operates in plug-and-play mode, so it requires no batteries or installation—simply connect it between the charger and the device. Equipped with a USB-A plug (input) and a USB-A socket (output) in the 2.0 standard, it ensures easy compatibility with popular accessories. A clear, backlit LCD display shows operating parameters in real time, making it easy to diagnose cables and AC and car chargers operating within the standard USB voltage range.

Accurate diagnostics and charging monitoring

The device measures voltage and current with high accuracy, allowing you to assess whether the charger is functioning properly and whether the cable is causing energy loss. The capacity (mAh) measurement feature lets you check the actual amount of energy delivered to the device, making it easier to compare the performance of different chargers or cables. Additionally, the memory that stores up to 10 measurements allows you to review results for different devices without having to write them down. The compact housing makes the tester convenient for everyday use and fits easily in a pocket or accessory bag. It enables early detection of irregularities in the operation of a charger or cable, which helps limit the use of potentially defective accessories. However, please note that the device supports voltages in the range of 3–9 V, so it is not intended for testing fast chargers operating at higher voltages, such as certain Quick Charge or Power Delivery modes (12 V and above).