Mini 5pcs DC 4.75-23V to 3.3V Buck Converter Board - 1.8A Output, Small Size, Green

I used this to make a power supply to replace 2 - 1.5 volt batteries. I connected it to a USB power cube. Works great. Voltage output is 3.3VDC.

I bought these switching type 3.3 regulators to replace some 3.3v linear regulators that just didn't cut it and kept blowing up. So far these have done their job well and don't get hot like the linear versions.

Mixed report. 4ea worked fine, but 1ea a resistor fell off in transit (poorly soldered) and was floating free in the bag. Quiescent current draw is 7ma. BTW: Outside of my expertise, but worth mentioning just in case the following is uncommon. If you disconnect supply power to the input of this module, any power source (e.g. a 3.2v backup coin battery, or a MCU programmer) that is connected to the output side of this module will meet a 300mA load. (This may be common to all buck converters, worth checking into)

I have a few hundred partly used C batteries that are all at about 1.4V from a piece of medical equipment that requires a fresh set every day. This regulator lets me hook up six of them at 8.4V and drain them to under a volt each, giving me a constant 3.3-ish volts the whole time. I didn't read the title and description (4.7V-23V) closely enough and started with three batteries at 4.2V, which caused the regulator to output only 1V. I contacted the seller and they replied very quickly and even tested some regulators at 4.2V to verify my results even though I clearly misread how to use them. Very impressive response!

Running from 9v these little buck convertors produce a steady 3.3v output no heat issues or failures at around 70% duty cycling.

Beware of the warning in the product description about the voltage drop to 3V at 1.5A. I tried it with Walksnail 1S VTX that draws 1.2 Amp, and it drops to 3.2 Volt or lower, so the Walksnail 1S shuts down before fully booting up. They put in the effort to reduce the weight. See the attached weighing picture.

These are perfect for an ESP-01S. You can stick them on to the back of an ESP-01S with double sided foam to make a very compact module.

Of the 5 parts only 4 were capable of delivering the specified high current output. The oddpart delivered the correct output voltage but only regulated to about 1/4 amp before cutting back the output voltage.