Queta 6 Pieces LM2596s DC to DC Buck Converter Step Down Voltage Regulator Power Module 3.2-40V to 1.25-35V 3A High Efficiency DC Voltage Stabilizer Volt Transformer LM2596 DC-DC Buck Converter

These Queta DC-DC Buck converters work great! All six of the DC converter modules I received today performed exactly as expected. When the output is set to 3 volts, their output voltage only sagged about 10 mV when drawing a half amp, so they are regulating the output voltage pretty well under load. A WORD OF CAUTION to people who are not used to working with these buck converters - it may seem at first like they are not working correctly. When you first take them out of the package, they are typically set for maximum output, so the DC input and output voltages will probably be the same. So this means that initially you should NOT hook up the device you intend to power with this buck converter. You MUST first set the output of the module to the desired output voltage level, before you connect your device to it, or you could potentially FRY the unit that you were intending to power this converter with! When you power the module up, set the DC input voltage to the buck converter to somewhere between 7 to 14 volts DC. Using a jeweler's screwdriver, turn the small brass screw on the blue trimpot about 10 turns counter-clockwise. Assuming you are monitoring the module's output with a DC multimeter, after you surpass 9 to 10 turns of the trimpot you should start to see the output voltage drop. Now adjust the trimpot until you reach the intended DC output level. For a 3W "star type" high power LED, this could be about 3 volts. For an Arduino Uno, it might be around 6V > 7V. One other thing you might want to check before permanently wiring the module to your intended load device. With the converter module powered up, monitor the DC output voltage to make sure that when you connect your device to the output, make sure that the output voltage does not "sag" too much. If the voltage drops by more than say ~ 30 to 100 mV when you connect your load device, there might be a problem .... otherwise it is probably working just fine.

I have a farm and on that farm I have some cameras. Actually quite a few. Many are in remote corners where I have no power so I utilize solar panels and LiFePO4 batteries. To keep the batteries charged I made camera poles that have a solar panel on top and the camera below for shade during the hot day. I use these devices to limit the output to the current to the correct voltage to charge the batteries during the day. So far they have worked perfectly. One thing I do that might give me better results is that I use a Conformal Coating on them to protect the electronics from moisture. This is an electronics spray used to coat electronics with a protective barrier for moist environments. I apply this to all of them before putting them outdoors to use. I keep these on hand for many other uses as well. Great little devices as ling as you do not exceed their rated capacity.

I've had one of these in my truck dashboard powering a 3V device from the 12V system for over a year. No issues.

Used the first of these to power a Raspberry Pi 4 with LCD screen, which kept reporting low voltage using a 5v supply with plenty of capacity. Problem was that powering the RPi4 through the LCD screen resulted in a slight voltage drop, and the RPi4 was getting a touch under 5v (and is VERY picky). Used this to run it from my 3D printers 24v power-supply with an output voltage of 5.15v, which has been completely stable. I even tested running it from my bench power supply and changing the input voltage pretty widely, from 18-26v and the output was still pretty stable. I've since used another one of these for powering other devices when I need two voltages from my single output bench power supply. (e.g.: 12v and 5v or 5v & 3.3v etc), and has been reliable (over a short time thus far). My only gripe is that they do get a little toasty when running and are a little less efficient than should be possible with the LM2596 regulator (though at the in/out voltages I've been using even the datasheet rating isn't exactly great efficiency ... these were just a bit below that rating). An extra heatsink on the regulator chip may help, and depending on your application some forced airflow might be a good idea in any sort of enclosed space.

Does the job

I am very happy with these buck converters. They run cool for my application. Running 24 volts input set for 12 volts output, drawing about an amp. Very stable well regulated output stay within a couple hundreds of a volt output. From no load to full load. Very impressive for such a compact product. Plenty of adjustment from a multi turn precision pot.

I got these to convert some shelf items from batteries to USB plugs and the LED lights needed to be on a lower voltage setting than straight USB. Worked perfect and I was able to adjust it to the perfect voltage. Easy to solder to as well.

Read the directions turn it counterclockwise a few times until the voltage starts to go down easily adjustable nice components works well. I have 12 and 1/2 volts DC going in and five volts coming out.

Components are not as shown in the graphic. 1) The output filter cap is only 100uf, the picture shows 220uf 2) The input filter cap is only rated at 35V, not 50v, which is too low considering the 40V input claim, which would fry them. Anything over 30V is likely pushing it 3) Filter cap grade, the picture shows RTV (220up 50v). CS is what is on the board I received, which is the lowest rating. Make sure the caps have at least a VS rating VT is better RVT is better than VT. These are what remain after failing all other quality tests. 4) The inductor is about 1/3 the physical size of similar boards; this matters for proper heat dissipation. It will not last long if run with a heavier load for more than a brief time. 5) Packaging is poor. A regular plastic bag was used, not a static-safe one. This is an extremely low-quality, misrepresented product. You can get the same board with far superior components for a similar price. If your intent is to use this product with an input under 30v at low current levels and for testing only, it will likely work. Don't touch it if you are building something more permanent or complex. Given the very low-quality parts used, my guess is the reset is at the bottom of the bin, too. Possibly even knock off LM2596. You can get way better filtering, consistent performance, and longevity by using a different brand/vendor. These boards may look the same, but they are not. I'll be returning the product as it is not what I was looking for and not what was advertised.