Review on FULARR Converter Step Down Regulator Adjustable by Mike Rogers

Ordering a batch of these power supplies for use in a battery monitoring installation. The project board shows the power supply (top left), the voltage sensor, the NodeMCU, the temperature/pressure sensor and the OLED display. The power inputs, rated for 12 VDC, supply a regulated 5 VDC to the NodeMCU's VIN pin. In addition, the power supply input (nominally 12 VDC) supplies current from the source to the voltage sensor. Unfortunately, I used a small 9V DC battery as the power source during testing, and USB power was connected to the USB port, allowing me to program the NodeMCU using the Arduino IDE. It worked fine for the most part. However, when I moved the project board back to a real solar panel (nominally 12V DC) and then reconnected the USB power supply so I could calibrate the sensors, the power supply burned out and also destroyed the NodeMCU (I didn't test other sensors) . or OLEDs, but can also be fried). The NodeMCU has a built in diode to prevent USB power from being reversed to the VIN pin, so I'm not entirely sure why this happened. The supply voltage at that time was 14VDC, but that shouldn't matter. Anyway, the power supply burned out and took the NodeMCU with it. DISSATISFIED.