UMLIFE 10PCS AC/DC to DC Step Down Buck Converter AC 5-30V DC 5-48V 24V 36V 48V to DC 2.5-35V 12V Voltage Regulator Board 2A Adjustable Volt Power Supply Module

The LM2596HV is a great chip for building a buck converter, and this particular product is pretty much an exact implementation of the reference design. So, I would expect good performance overall. Much to my surprise, that wasn't at all the case with the first board that I took out of the package. No matter how I adjusted the precision resistor, the output voltage always equaled the input voltage. That's not good at all. In fact, that can do a lot of damage to anything connected to the output terminal block.I tried to check for problems. and as the adjustable resistor readings were obviously bogus, I removed that part and replaced the component with a known-good resistor. Same results.Next, I closely inspected the board, and the problem quickly became apparent. The integrated circuit is a through-hole component, and despite being soldered from the bottom, there were giant blobs of solder on the top side of the board shorting out the pins. After cleaning up that mess and redoing the soldering, everything works now.Overall, I like the board. The price is good, and the LM2596HV does exactly what I want it to do. But there apparently is no quality-control at all. Not only can't I even begin to guess how so much solder made it to the wrong side of the board, this particular mistake would have been blatantly obvious the moment anybody tested the board. The buck converter wasn't even doing anything at all.Considering the price, this is still a fine purchase. But expect to have to rework the boards. And whatever you do, don't connect them to anything until you have fully tested them.Edit: Found another buck converter in my set that clearly should not have passed quality control. I was missing the terminal block for connecting the wires. Easy to fix with a soldering iron, but that should not have been necessary.

For some alarm systems that are 24 volt dc panels we needed a way to convert 24 to 12 vdc. I forgot to read the description but these did the 24 to 12 anyway. Awesome little product for two bucks a pop. Plus the pin hole screws are very convenient for small wires. VERY USEFUL!

Just a complete waste of time. On the bench top they work. After a few weeks in use every single one has failed. I'm an electrician I know how to use these. They are garbage. DO NOT BUY.

Would not accept 24 VAC and stability make any VDC my project called for 24 VDC I could have used 12 or anything in between but could not get a stable voltage out of any of them.