DC-DC Buck Boost Converter,Regulator CC CV 0.5-30V 0-4A Adjustable Regulated Power Supply Module DIY Solar Battery Charging Module LCD Display ZK-4KX 1 Pack

What I didn't like is the terminals that connect the wiring are of lesser quality meaning its easy to ruin the screws with a small screw driver. Works good though. sweet little power supply for my HO train.

I bought 2 of the dc-dc buck boost converters, one for me and one for a coworker. One of them did not work when received, but a new one was sent out, and the return was quick and easy.I’ve used it to power a couple small projects, but my primary reason for getting it is to charge battery cells, and be able to control the maximum current supplied. The instructions are not good. I found “better” ones online, and attached the screen captures of them that may help someone else. It’s just figuring out how to get around the menus. I use a 12V 3A dc wall supply for what I’ve needed so far.

These things tend to overheat and die if you go anywhere near the max rating. I have 6 of them.

If minimal functions in this dept fill your bill, then this 2-pack is a good deal. Just adjusting voltage from 12VDC to 3VDC this works fine @2A. If you need more sophisticated control, spend 2x for one and you can control most everything.The two variations are not interchangeable.

The media could not be loaded.  I bought this buck converter to add variable frequencies to a bench power supply I am making. The unit is well made and has a reasonable capacity of 4 Amps. Hooking it up is very simple with two wires in, two wires out. Comparison of the display with my VOM match well.One surprise was the fine control of the voltage level. You have to turn the voltage control not A LOT to change the voltage. I had expected each click to be 1/10 a volt or similar but it is much finer. It is hard to make large voltage changes.. however the control is very precise. For my use this isn't a problem because I won't change it often.The unit came without any documentation. The sales listing has some, and more can be found on the web. The unit has lots of capabilities beyond what I need.Overall - works well and highly recommended.