MT3608 DC-DC Step Up Boost Power Converter - 2A Module, Adjustable Step Up Voltage Regulator Board - 2-24V to 5V-28V Output Voltage (Pack of 10)

I received 10 boards and tested 1 of them and did not work with 4.1v input. No change in output voltage regardless of potentiometer. Tried two more boards and they are the same. The boards should work with greater than 2v but did not work. I am returning them no point of checking remaining 7 boards.After further testing none of the boards are defective. The issue is that you need to turn potentiometer at least 20~30 turns all the way both sides and at one point output voltage will increase. Turn until u hear click sound. If no change then turn opposite direction and it should work but many turns in that direction.

I saw the copious negative reviews for these, but they were dirt cheap so I gambled anyway. I rapidly tested three modules on my bench just to see what all the fuss was about. They all worked perfectly fine. Even with 3.4V input I could take them past 20V output at moderate load. At lower voltage delta, I could push them past an amp. Yeah, voltage will sag at high loads, so adjust based on your load. Voltage was reasonably stable for a given load and pot adjustment. At certain points I could hear some switching harmonics, but that’s normal.I think people need a reality check. You want a truly constant voltage power source? You ain’t getting it from a <$1 module. Sure the listing rates these at 2A, but also use some common sense. That’s probably an intermittent maximum rating and it very much depends on how much of a step up you are asking the little device for. More realistically, put a realistic power expectation in your head and understand that you need to derate as you increase the step up. I tested 12Vin and 16Vout with 2A output and had no issues. Efficiency drops as voltage delta increases. It’s a tiny little switcher IC and there’s no heatsink. Play stupid thermal games with it and win stupid thermal prizes. You want a comprehensive datasheet with exact thermal and load ratings? Go spend more money or build your own to spec. If you don’t understand that most trimmer pots are 20 turn, don’t play with module level components. If you just want a really cheap way to step up a voltage and you have realistic power expectations based on the size of this little IC, hard to beat these.

Two of these failed immediately. Other two worked for a while. I am using 2 of them simultaneously for two circuits up-converting from 12V to 24V, powering a 16W circuit. But both of them failed within a few hours of use. The failure resulted in them producing only the input voltage at the output. I am on the last one (of the 5-pack) and I expect it to fail as well. Very unpleasantly surprised. Actually heavily disappointed. I removed 1 star for each failed board from the 5-pack.The ad says that these up-converters work with loads up to 2 amps. I am using them only for 0.7A each so they should be able to handle that just fine. But they do not. I requested a replacement package, foolishly hoping that another batch might work better. I will post an update once I test them out.Though I should not fail to provide more details about the up-converters. They come with nice pre-drilled solder pads, they are big enough for bigger wires for 2 amps, that is a nice touch. The adjustment trim-pot is pretty funky, the quality really is not good because when it is turned maybe 1/4 turn, the voltage barely changes, then it is just barely touched and now the output voltage jumps an extra volt. The trim-pot operation simply is not smooth enough for fine adjustments. Otherwise, once the trim-pot is adjusted, the board holds the output voltage well, no big deviations, maybe a tenth of a volt but that's also the reading error on my DMM so it's hard to tell. Size of the boards is acceptable and as advertised. If I ever get any that will actually stay working, I will slide them into a 1.5" heat shrink sleeve for protection.As far as the refund goes, I have been waiting almost a month. I have neither the boards, nor my money. On the product returns page, Amazon indicates when I should receive the refund. Whenever the date comes up, they move it out. The return page shows "Refund issuance is delayed". No explanation. Amazon is pretty good about issuing a refund once they receive the merchandise but they've had the boards 2 weeks and no refund. I wonder about their actual procedural policy and why the process is stuck. Disappointed on this front as well.