5Pcs LM2596S Driver DC-DC Constant Current Module, Dorhea LM2596 DC-DC 7V-35V Step-Down CC/CV Power Supply Module Battery Charger Adjustable LM2596S Voltage Converter Current Charging Board

They seem to work just fine. As with all things in life. Verify. In my scenario, 13v down to 5.6v, they are good for about 1.5 amps with a small heat sink on the chip and another on the inductor. I put thes on a 5v 1.5 amp load and then set them so that the current starts to roll off and drop the voltage at that point. This way your entire world doesn't melt down and destroy itself. Personally, when I look at these kinds of things, I always cut the marketing numbers by at least half. The math on these actually seems to work when constrained by this kind of marketing to real life math.

Boy are these things useful. Takes any DC voltage from 4.5 to 53 volts and drops it to any voltage from 3v up as long as the output voltage is 1.5 volts less than the input. They are switchers so they're about 95% efficient so going from 48 volt power over ethernet down to 5 volts doesn't burn up a lot of energy unlike old-fashioned analog regulators. I use them to run 12 volt fans at 9 volts to make the fans run really quietly while still moving a decent amount of air.

These little converters work fairly well as long as you don't set the bar too high. It is amazing what you can get these days for less than $3\piece. I have used three out of the five and so far I haven't had any issues at currents less than one amp continuous.Pros:- Low idle consumption at about 0.5W. Some other units had issues with the voltage regulator for the display. However, these seem to have resolved that. Idle temp is about 115F (46C) on the regulator.- Switch to toggle between input and output voltage display.- Fairly precise potentiometer for easy fine tuning.Cons:- Not 40V, I wouldn't supply anything over 30. The input cap is rated at 35V.- Gets toasty running 2 amps - 217F (103C) on that poor Schottky diode. With input at 20V and output at 10V, 2A the dissipation is roughly 4.5W (about 20% loss). I wouldn't run them at anything over 2A for extended periods...- I tried finding a case to 3D print... there are about 4-5 different board sizes so take measurements before ordering\printing.Overall, if you plan on using these at less than 30V input and 1-1.5A continuous\burst you will be just fine. These are not designed for current limiting. They will only regulate output voltage. I doubt they have any protection so if you accidentally short it or send 4-5 amps through it it will likely blow up.

Great product and price. Using with noctua fans on my 3d printer. Easy to wire, easy to adjust voltage. Very happy with the product.

I wouldn't recommend using these at anything over 1.5A unless you're prepared to actively cool them with a heatsink that covers the entire back side. At 2A they get hot enough to actually burn you if you touch them. It won't take long for something to fail at those temps.That said they operate comfortably at 1A all day long. It's a handy board to have around in a pinch but I'm disappointed I won't be able to use these in the batteries I'm building. Charging a 24Ah battery at 1.5A just takes too long.

It fits in small places and does a great job.

Tried all five and none of the adjustments worked simply stayed at the input voltage.

I like that these are inexpensive and they work up to a point. The regulators I'm talking about are the LM2598HV based ones with the extended input voltage. The description says the output can be adjusted up to 40 Volts. However, the output capacitor is only rated 35V. So, unless you want to run the capacitor over-voltage you are limited to 35V. Typically, capacitors are not run at their rated voltage to lengthen lifetime but there you have it. Also, at 1.5Amps 48V input, 35V output, the LM2598 runs extremely hot to the touch. Heatsinking is certainly needed even at 1.5 Amps. I desoldered the device and inserted a copper tab of a 1" x 1" x 2" "L" shaped copper, 22 gauge and resoldered the sandwich. That helped a great deal. They sell these with heatsinks but the output voltage is specified lower (probably correctly so). I also saw other similar modules on Amazon with heatsinks glued to the top of the LM2598HV device. This is not very effective heatsinking since the plastic case of the device has a much lower thermal conductivity than the tab of the device.

I gave up after 3 of them died on one the chip exploded all they were powering was a 12v halo angel eyes led ring lights on my bench unit they show that the current draw is only 0.28 amps.

Just right for it's intended purpose. Much easier to adjust than similar products because of the built in LCD display.