Review on Adjustable Automatic Voltage Converter Display by Jarrett Francis

First, the listing says it's a boost converter, but it's just a buck converter. It's also terrible as a buck converter. The voltage is in the range of 0.05mV, which is not very good, but is sufficient for most cases. On the other hand, the ripple is terrible, from 100mV to 500mV! Good for an LED, but not for charging batteries or powering ICs. In DC operation this is completely hopeless. It jumps between the set current and 0. The LEDs create a play of light and the batteries take a long time to charge. The best that can be said about him is that he does not exceed the current limit.