[Dylan16807]

> A lot of what makes real (UL/ETL listed) chargers expensive is making sure that line voltage stays adequately separated from the low voltage side.

Even a very cheap and simplified design can do that. I wouldn't say "a lot" at all, maybe a few percent of the cost at most. It's a corner that could possibly be cut, but it's not one of the bigger corners.

[kens]

I've done a lot of charger teardowns, and very cheap chargers always violate UL safety rules. It's a combination of cost (e.g. triple-insulated transformers), it's hard to fit clearance distances into a small charger, sloppy manufacturing, and they don't seem to even try.

[microtherion]

I respect your superior expertise, of course, but looking through another site that has done systematic teardowns and measurements (https://lygte-info.dk/info/ChargerIndex%20UK.html), it appears to me that this might be too categorical a statement. While counterfeit chargers almost always seem to be dangerous, there seem to be some Chinese brands which produce quite respectable chargers, while still being fairly inexpensive.

[jdietrich]

The point is that you don't know. A legitimate branded charger will have been tested in a certified test lab, while an off-brand or counterfeit charge is likely to have a counterfeit UL mark. It might be perfectly safe or it might be a complete deathtrap, because nobody has actually tested it for compliance.

[joshu]

I need a bunch of chargers for a sensor network (Right now using Wemos D1 Mini boards). Any advice on optimizing for price without compromising on safety? I don't trust the sellers that sell $2 chargers...

[jdietrich]

Anker, Aukey and Blitzwolf make reasonably priced and high quality chargers.

[taivare]

This summer I, had a dehumidifier plugged in with a 3-prong connector . . good thing I, checked it shortly after I started the unit ,the adapter was very/warm . . a short in a cheap adapter . . went to electric supply store and made sure I got a high quality UL rated brand.