USB Adjustable Discharger Module – Constant Current Electronic Load

The USB-DISCHARGER is a compact electronic load module designed to discharge and test USB power sources, power banks, and battery packs under controlled constant-current conditions. It connects to the device under test through a standard USB Type-A interface and draws a user-adjustable current, allowing the operator to measure actual battery capacity, verify rated output, and simulate realistic loads during product ageing tests. Unlike simple resistive dummy loads with fixed current steps, this module provides continuously variable current control across a 0.15A to 3A range.

The module operates from an input voltage of 3.7V to 13V DC and supports a continuous discharge power of 15W. At 5V the full 3A is available (15W), while at 13V the current is limited to approximately 1A to stay within the 15W envelope. A precision multi-turn potentiometer on the board adjusts the constant current setpoint, and the load maintains that current as the source voltage changes, which is essential for accurate capacity measurement. A built-in intelligent cooling fan activates automatically when the internal temperature exceeds approximately 40°C, and without the fan the module can dissipate approximately 7.5W continuously. The anodised aluminium heatsink body measures approximately 24 × 30 × 40mm, with a total protruding length of about 25mm at the USB plug, and weighs 25g without the fan or 35g with the fan.

Because the module dissipates the tested energy as heat, the body can reach temperatures of around 120°C during sustained high-power operation. Users must avoid touching the heatsink during or immediately after use and should keep the module away from flammable materials. The USB discharger is intended for bench testing, quality control, repair workshops, and battery capacity characterisation; it is a passive load and does not include a display, data logging, or Bluetooth connectivity.