Summary: most no-name USB chargers are shite. They don’t put out the rated amperage, and even if they do it’s so noisy that you won’t want plug anything into it that you care about. Oh, and a lot of them stand a non-trivial chance of running mains voltage where it shouldn’t be.
The author did find three good ones, though. I think today’s task is to dig through that box of USB chargers and throw 2/3 of them away.